KR0178872B1 - Stereolithographic supports - Google Patents

Abstract

Specially adapted to provide support for objects on a selected surface of a fluid medium that can change its physical state in response to suitable synergistic stimulation by radiation, particle bombardment, or chemical reaction An improved stereo lithography system for generating a three-dimensional object by generating a cross-section pattern of a three-dimensional object to be formed using true object definition information is disclosed. These systems reduce warpage and distortion and increase the resolution, intensity, accuracy, speed and economics of regeneration. By automatically joining successively adjacent laminae corresponding to successive contiguous sections of an object and combining and integrating them to provide stepped reminiscent of a given object, a three-dimensional object is formed and a fluid Is drawn from a substantially flat surface of the medium. A stereo lithographic support for an object is described, including a preferred embodiment known as web support.

Description

[Title of the Invention]

Stereolithographic supports

DETAILED DESCRIPTION OF THE INVENTION [

BACKGROUND OF THE INVENTION [

1. Cross reference to related application

This application is related to United States Patent Applications Nos. 182,823, 182,830, 183,015, 182,801, 183,016, 183,014 and 183,012, filed on April 18, 1988, Are fully incorporated herein by reference.

A continuation-in-part of U. S. Patent Nos. 182,830, 183,016, 183,014 and 183,012 was filed on November 8, 1988, all of which are fully incorporated herein by reference. It is the continuation of part of U.S. Pat. No. 182,830 filed in U.S. Application No. 269,801, No. 268,816, No. 268,337, and No. 268,907, respectively, of some of the above-mentioned continuation applications, and No. 268,429, 268,408 is a continuation-in-part application to No. 183,014, and 268,428 is a continuation-in-part application of No. 183,012. Some continuation applications to U.S. Patent Application No. 269,801 were filed on March 31, 1989, the entirety of which is incorporated herein by reference.

2. Cross reference to attached appendix

The following appendices are attached, which are fully incorporated herein by reference.

Appendix D: 3D Systems Inco Operated, SLA-1, Training Manual, Version 3.0,

(April 1988)

3. Technology of the invention

FIELD OF THE INVENTION The present invention relates generally to improved methods and apparatus for forming three-dimensional objects from a fluid medium, and more particularly to advanced data manipulation and lithographic techniques for generating three- Relates to a new and improved stereolithography system related to making objects more quickly, reliably, accurately, and economically by applying them. In particular, the present invention relates to the support required for stereo lithography of objects.

4. BACKGROUND OF THE INVENTION

In the production of plastic parts and the like, it is common to design these parts first and then to hard produce the original parts of the parts, all of which require considerable time, effort and cost. Since the design is reviewed only after that, sometimes the design is optimized only after the above-mentioned difficult process is repeated again. Once the design is optimized, production takes place in the next step. Most mass-produced plastic parts are made by injection molding. Since design time and tooling costs are very high, plastic parts are only practical for large-scale production. Processes such as direct machining operations or vacuum forming and direct forming may also be used to produce plastic parts, but these methods are typically cost effective only for short-term production , And produced parts are generally of lower quality than molded parts.

Conventionally, a very complicated method for creating a three-dimensional object in a fluid medium has been developed, which uses beams of radiation to selectively focus a selected intersection in a three-dimensional volume of fluid medium Thereby forming a three-dimensional object in the fluid medium by selectively curing the fluid medium.

Typical examples of such three-dimensional systems are described in U.S. Patent Nos. 4,041,476, 4,078,229, 4,238,840, and 4,288,861. All of these systems depend on the way in which synergistic energization is built at selected points deep within the fluid volume, leaving all other points within the fluid volume intact. Unfortunately, however, these three-dimensional forming systems are faced with a number of problems related to resolution and exposure control. It can be seen that the control becomes complicated due to the reduction of the radiant intensity and image forming resolution of the focused spot as the intersection deeply moves into the fluid medium. Absorption, scattering, scattering and diffraction all add to the difficulty of realizing deep working in fluid media in an economical and reliable manner.

Recently, a stereolithographic system such as that described in U.S. Patent No. 4,575,330 (which is referred to as part of this specification), which is an apparatus for producing a three-dimensional object by stereolithography, is used. Basically, stereolithography refers to the continuous printing of sections of a photopolymer (such as liquid plastics) on top of each other such that these thin layers are joined together to form a complete single piece, Is automatically constructed. Using this method, the part becomes complete in the water vat containing the liquid plastic. This manufacturing method has an extremely powerful effect in quickly shortening design time into physical form and reducing the time required to make a prototype. Photocurable polymers change from liquid to solid with light, and have very fast photosensitivity to ultraviolet (UV), making them well suited as practical modeling materials. While the part is being fabricated, the non-polymerized material remains in the bath and can be used continuously while the part is being manufactured continuously. Ultraviolet lasers generate small, intense ultraviolet spotlights. The spot is moved across the liquid surface by a voltmeter mirror X-Y scanner. The scanner is driven by a vector generated by a computer. With this technique, it is possible to produce precise and complex patterns quickly.

The laser scanner, photopolymer bath, and elevator combine with the control computer to form a stereo lithographic device, called SLA. SLAs are programmed to automate the production of plastic parts by stacking them one at a time and stacking them one at a time.

Stereo lithography is a new way to quickly create complex or simple parts without the need for mold making. In this technique, since a computer is used to generate the cross-sectional pattern, it is natural to link the data to the CAD / CAM. However, such systems have problems in manufacturing shapes of particular objects as well as problems related to shrinkage, curl, twist, resolution and accuracy.

Support is shown in the drawings of U.S. Patent 4,575,330, which serves to attach an object to a platform.

The kind of post (support column) / support originally used was actually formed by curing a single point. These points are cured for a certain length of time so as to have an appropriate curing depth and a corresponding curing width. This kind of post is limited in its strength, and there is also a limit to the associated curing time required to achieve this level of strength (even if a given strength can be obtained).

Another type of post / support was generated depending on the need to increase the interlaminar bond strength. The bonding strength is proportional to the contact area between the layers. As the hardening width quickly reaches a critical point where no further hardening width is possible by hardening any point, another method for increasing the contact area has been implemented. This new method uses a support with a polygon in the cross-section instead of curing a support with a point vector in the cross-section. Such a polygon can be a triangle, a rectangle, an octagon, or the like. With this structure, the contact area between the layers is much larger (the contact strength becomes stronger) and the structural strength for horizontal translation is also greater. While these supports have shown reasonable effectiveness, they are: 1) difficult to remove from the object; 2) provide support only for a limited number of object vectors; and 3) It still has the problem of using a base to support the polygon for attachment.

Denshi Joho Tsushin Gakkai Ronbunshi, 71-D Volume 2, February 1988, pages 416 to 423, written by Takashi Nakai and Yoji Marutani, [0004] Basically, two different approaches have been described, namely the so-called free liquid level technique (liquid surface technique) A technique in which irradiation is effected by a laser beam from the atmosphere side) and a restricted liquid level technique (a technique in which irradiation of a liquid surface is performed through a transparent surface that interferes with liquid). Both right side-up and upside-down embodiments for the limited level approach are disclosed.

With respect to the downside-up embodiment of the limited liquid level technique, when removing already frozen parts of an object from the transparent plane so that fresh liquid resin can flow through them for the next layer, It is mentioned that problems arise in the prior art system because the resin tends to stick to a transparent plane. This problem is particularly acute in the part of the object where significant transitions occur between different cross-sectional layers because only a part of the new layer, basically corresponding to the cross-section of the previous layer, is removed from the plane and the remaining part is split and remains in the transparent plane. To solve this problem, the strength of the layer is increased by adding an external support structure and scanning the laser repeatedly to form respective portions.

Another construction technique is to use the so-called vector scanning method. This method only tightens the outer surface of the object, that is, the outline of the object.

For parts formed using this method, especially for parts with rectangular cross-sections, the problem is that the walls of the object tend to extend slightly outward. In order to suppress such expansion, it has been proposed to construct internal ribs.

In European Patent No. 250,121 (forming the preamble of the independent claim), a modeling device for forming a three-dimensional object on the lower surface of a container containing liquid is known. It has been mentioned to provide cylindrical bulk support legs having a thickness determined by the load to be supported, in order to form a complex body with isolated portions. It is also mentioned to provide an intermediate support for securing two parts of an object formed relative to each other. This intermediate support is achieved by providing a horizontally extended support mesh that joins the isolated portion.

[Summary of the Invention]

It is therefore an object of the present invention to provide a stereo lithographic apparatus and method which can further improve the accuracy of the part to be constructed and also reduce the production time. This object is solved by a stereo lithographic system according to claims 1 and 2 and a corresponding method according to claims 22 and 23.

More specifically, the stereo lithographic system according to the present invention provides two distinct types of support structures that can significantly improve component accuracy and reduce production time. According to the first embodiment, a web support having a vertical structure is formed to support the downward characteristic of the object formed in the upward direction. By using this kind of support structure, even a very thin layer can be produced very accurately without using a transparent plane. Thus, the attachment problems associated therewith can be solved. By using the support structure according to the second embodiment, this support structure can be effectively applied to the geometry of a complicated part.

Other preferred embodiments of the invention are defined in the dependent claims.

Another advantage of the present invention is that the drain of the part can be made faster and better. The present invention fixes a free floating boundary (i.e., allows the perimeter to remain in place until the cross-hatch is drawn). Torsion, stress associated with dipping, and deformation due to the weight of the part. The present invention fixes a component section that is not attached to anything else (until another layer is drawn later).

According to a preferred embodiment of the present invention for illustrative purposes only, the present invention combines the principles of computer graphics with a stereolithographic method, i.e., by applying a lithographic technique to the production of three-dimensional objects, Computer Aided Design (CAD) and Computer Aided Manufacturing The present invention can be applied to form models and prototypes at the design stage of product development, and can also be applied as a manufacturing system, or even as a form of art.

Stereolithography is a method and apparatus for producing solid materials by continuously printing thin layers of curable material, e.g., curable materials stacked on top of each other. A programmed movable ultraviolet spot beam is applied to the surface or layer of the curable liquid to form a solid cross-section of the object on the surface of the liquid. Thereafter, the object is moved in a programmed fashion by one layer thickness from the liquid surface, and the next section is then formed and attached to the immediately preceding layer defining the object. This process continues and a complete object is formed.

All types of object shapes can be fabricated using the technique of the present invention. By using the computer function of generating a program command and then transferring the program signal to a stereo lithographic object forming subsystem, complex forms can be made easier.

Of course, other forms of appropriate synergistic stimulation for the hardenable fluid medium, such as bombardment (electron beam or the like), spraying the material through a mask, Chemical reaction by the laser beam, or other radiation that is not ultraviolet light, can be used in the practice of the present invention without departing from the spirit and scope of the present invention.

For example, in the practice of the present invention, a continuous section laminae can be obtained by appropriately bringing a body of fluid media that can be solidified in response to a given stimulus into a suitable container first, Lt; RTI ID = 0.0 > fluid < / RTI >

A suitable type of synergistic stimulus, such as a spot of ultraviolet light, is then applied in a graphic pattern on a designated working surface of the fluid medium to form individual layers of thin solids on the surface, Dimensional object. According to the present invention, information defining an object is specially processed to reduce warping and twisting, increasing the resolution, intensity, accuracy, speed and economics of reproduction.

When each layer is formed, successively adjacent layers with respect to each other are automatically superimposed, and the layers are joined together to define a predetermined three-dimensional object. In this regard, a suitable platform to which the first laminar was attached may be formed by any suitable actuator, in a pre-programmed manner, as the fluid medium at the work surface is cured and the solid material is formed into a thin laminar form Away from the work surface, all typically under the control of a microcomputer or the like. In this way, the solid material initially formed on the work surface moves away from its surface, and new liquid flows into the work surface location. This time, a portion of this new liquid is converted to a solid material by a programmed beam spot to define a new laminar, which is adherent to the material adjacent to itself, that is, the immediately preceding laminar . This process continues until a complete three-dimensional object is formed. After the formed object is removed from the container, this device can be used to directly produce the same object as the first object, or a completely new object created by a computer or the like.

The database of the CAD system can take various forms. One of them is a method of expressing the surface of an object as a mesh composed of a polygon, typically a triangle. These triangles constitute the entire interior and exterior surfaces of the object. This type of CAD representation also includes a unit length normal vector for each triangle. This normal line indicates the direction in which the triangle moves away from the central portion constituting the outer surface and shows a slope. The present invention provides means for processing CAD data, which may be provided as PHIGS or similar, into layer-by-layer vector data that can be used to form a model via stereo lithography . This information may ultimately be converted into raster scan output data or the like.

As described above, stereolithography is a three-dimensional printing process in which components are fabricated by solidifying a continuous layer of liquid plastic using a movable laser beam.

Using this method of applying the concept of the present invention to reduce rolling and stress, a designer can create a design on a CAD system and provide appropriate support to produce accurate plastic models within a few hours. The stereo lithographic process according to the present invention may comprise the following steps.

First, solid models are designed in the usual way on a CAD system without specific reference to the stereolithographic process. In model preparation for stereolithography, optimal direction selection, addition of support, construction of appropriate stress reduction means, and selection of operating parameters of the stereolithographic system are involved. The optimal orientation is to (1) allow for drainage of objects, (2) minimize the number of unsupported surfaces, (3) optimize critical surfaces, and (4) allow objects to be accommodated in a resin vat. It is the direction that makes it possible. Fix a non-attached section or add support for other purposes, and a CAD library of support can be prepared for this. Stereo lithographic operating parameters include selecting the scale of the model and the thickness of the slice.

Thereafter, the surface of the solid model is divided into triangles, typically PHIGS. Triangles are the least complex polygons in vector calculations. The more triangles are formed, the better the surface resolution, and the objects formed by the CAD design become more accurate.

Now, the data points representing the coordinates of the triangle and its normals, typically PHIGS, are transmitted to the stereo lithographic system via appropriate network communications such as Ethernet. The software of the stereo lithographic system then slices these triangular sections horizontally (parallel to the X-Y plane) for a given layer thickness (s1ice).

Next, the stereo lithographic device (SLA) calculates the section border vector, the hatch vector, and the horizontal surface (skin) vector. The hatch vector consists of cross-hatching between boundary vectors. There are several styles of slicing. The skin vectors are broadly superimposed and tracked at high speed, forming the outer horizontal surface of the object. The internal horizontal areas within the skins of the ceiling and floor are filled only by crosshatch vectors. A more detailed description of the vector is given in U.S. Patent Application Serial No. 182,830 and its part of Continuing Applicant Application No. 269,801, and in its continuation-in-part application No. 331,644.

The SLA now moves an ultraviolet beam or the like of a helium-cadmium laser across the surface of the photocurable resin to solidify the liquid where the beam hits, thereby forming an object horizontally one layer at a time. Since the laser light can not penetrate deeply due to the absorption in the resin, it is possible to form a thin layer. Each layer typically consists of vectors drawn in order of border-hatch-surface.

The first layer drawn by the SLA is bonded to a horizontal platform located just below the liquid surface. The platform is attached to an elevator that descends the platform by computer control. After drawing a layer, the platform is lowered by a short distance, such as a few millimeters, so that the previously cured layer is submerged in the liquid and then the new layer is coated with the new liquid, . After a brief pause until the surface of the liquid is flat, the next layer is drawn. Since the resin has adhesiveness, the second layer is firmly attached to the first layer. This process is repeated until all layers are drawn and a complete three-dimensional object is formed. Typically, about 0.25 inch at the base of an object is a support structure for fabricating a given part thereon. Resins that are not exposed to light remain in the bath and are used for the next part. Therefore, there is almost no waste of material.

Typically, post processing involves draining the formed body to remove excess resin, ultraviolet or thermal curing to complete the polymerization, and removal of the support.

Additional processing can also be performed, including sanding and assembling into an operational model.

According to the present invention, the support is provided in the form of webs. The web is a structure with a long, thin and square cross section. The width of the web is designed to be thin to facilitate removal of the web from the part after subsequent curing. The length of the web must be long enough to allow 1) to be well attached to the elevator platform (without the base), and 2) to be able to connect between cross sections of the object (to support the cross hatch and its surrounding border) To meet the requirements of

All these kinds of supports are used to attach an object to a platform (elevator), but it is also used to additionally support an important area of an object. These critical areas include the top edge of the window, the cantilever, and so on. The web may start from the elevator platform and be made to reach a section that needs to be supported, or may actually be made to reach another section that needs to be supported, starting from one section of the component.

The new improved stereo lithographic system of the present invention has many advantages over the devices currently used in the production of plastic objects. By using the apparatus and method of the present invention, there is no need for a design layout and a drawing, and a mold making drawing and a mold production are not required. Designers can work directly with computers and stereo lithographic devices, and if they find the design shown on the computer's output screen to be satisfactory, they can create parts for direct inspection. If you need to change the design, you can do it easily through a computer, and you can try to make parts once again to verify that these changes are valid. If a design for several components with mutually influencing design parameters is desired, the present invention permits rapid modification and re-production of all part designs to produce and review the entire assembly, and if necessary repeat all this The method of the invention becomes more useful. Moreover, the data processing techniques of the present invention can produce objects with reduced stress, strain, and distortion for demanding and complex object shapes, while increasing resolution, intensity, accuracy, speed, and economics of production.

Once the design is complete, production of the parts can start immediately, eliminating the time lapse of weeks or months between design and production. Stereolithography is particularly useful for short-term production as it eliminates the need for mold making and minimizes production preparation time. Likewise, design changes and custom parts can be easily implemented using this technique. Stereo lithography makes it easy to make parts, which makes it possible to use plastic parts in many places where metal or other materials are used. Moreover, you can quickly and economically create a plastic model of an object before deciding whether to make a more expensive piece of metal or other material.

Therefore, the new improved stereo lithographic method and apparatus of the present invention is an improved method of and apparatus for improving the quality of a three-dimensional part or the like with improved ability to quickly and reliably, accurately and economically design with reduced stress and strain, It meets a long-standing desire for CAD and CAM interface systems.

The foregoing and other objects and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which exemplary embodiments of the invention are shown.

BRIEF DESCRIPTION OF THE DRAWINGS Fig.

FIG. 1 is a schematic block diagram of a stereo lithographic system for practicing the present invention. FIG.

FIGS. 2 and 3 are flow charts illustrating the basic concepts applied in implementing the method of stereo lithography of the present invention. FIG.

FIG. 4 is a block diagram combining the concept of a system suitable for practicing the present invention and a vertical cross-sectional view. FIG.

FIG. 5 is a vertical cross-sectional view of Example 2 of a stereolithographic system for practicing the present invention; FIG.

FIG. 6 is a software architecture flow diagram illustrating the overall data flow, data processing, and data management in a stereo lithography system in more detail; FIG.

Figures 7a and 7b illustrate how the support fixes the layer boundaries in place until the cross-hatch vector is constructed.

Figures 8a-8b illustrate how a support prevents deformation and distortion of a cantilever beam-like structure.

Figures 9a-9b illustrate a method of attaching a support to a layer section that may not be adhered temporarily during the creation of the part.

Figures 10a-10b illustrate a method of preventing vertical web support from tilting the layer.

FIG. 11 illustrates the use of a diagonal support. FIG.

FIG. 12 illustrates a stereo lithographic process; FIG.

Figures 13a-13b illustrate SLA-1 and subsequent curing devices.

FIG. 14 illustrates the main components of SLA-1; FIG.

FIG. 15 illustrates an SLA-1 laser and an optical system; FIG.

Figure 16 illustrates a subsequent curing device.

17a to 17b also illustrate the position of a laser warning sign and a safety warning label.

FIG. 18 illustrates a test part; FIG.

FIG. 19 illustrates that a large number of triangles are required to approximate a curved surface.

Figure 20 illustrates that any arbitrary CAD object can be fully depicted by a flat triangle, an approximate flat triangle, and a steep triangle.

21 illustrates a method of generating a slice (.SLI) file by cross-sectioning a three-dimensional stereo lithography (.STL) file with a slice (SLICE);

FIG. 22 illustrates a method for determining whether cross-hatching or skins are required for a region between layer boundaries according to the type of triangle;

FIG. 23 illustrates a method in which the angle at which the triangulation changes from approximate flat to steep is defined by the SLI parameter MSA; FIG.

FIG. 24 illustrates an SLA-1 menu system; FIG.

Figure 25 illustrates a network (NETWORK) for transferring files over Ethernet between a control computer and a slice computer.

26 illustrates a terminal utility that allows a user to remotely operate a slice from a control computer; FIG.

Figure 27 shows that the MERGE function combines all files (support and object files) for a part to create layer (.L), vector (.V), and range (.R) Fig.

28 illustrates the display of a stereo lithography (.STL) file and a slice (.SLI) file on a control computer screen via a view function;

FIG. 29 illustrates graph creation of a .STL file. FIG.

FIG. 30 is a diagram illustrating graph creation of an .SLI file;

31-32 illustrate a BUILD state screen;

Figures 33a-33c illustrate the PCA at different stages during operation.

FIG. 34 illustrates an SLA-1 He-Cd laser; FIG.

FIG. 35 illustrates excitation and relaxation of photoinitiator molecules. FIG.

FIG. 36 illustrates a large change in viscosity due to a small change in temperature; FIG.

37 illustrates an intensity profile having a maximum near the center of the beam;

FIG. 38 illustrates that the change in refractive index improves the bullet shape. FIG.

FIG. 39 illustrates a method of determining the overall dimension of a bullet with a step period value; FIG.

FIG. 40 illustrates how an arbitrary point is severely cured if the step size is less than or equal to the maximum diameter of the bullet; FIG.

FIG. 41 illustrates a working curve. FIG.

FIG. 42 illustrates a banjotop; FIG.

DETAILED DESCRIPTION OF THE INVENTION [

Stereo lithography components are not built directly on the elevator platform, but are preferably made on structures known as supports. The first reason to use support is to isolate parts from the platform. It is difficult to remove parts that are hardened directly to the platform, especially when the adhesive surface is wide. Moreover, when the platform is twisted or improperly installed, the thickness of the first layer formed on the platform can not be precisely controlled, and the change may be intensified. The lines that are not deep enough to be adhered to the platform will be in a condition to promote the curl. Even without this potential problem, the holes in the platform will create corresponding bumps on the lower surface of the directly manufactured part on the platform. The liquid displacement when the platform is locked can change the thickness of the first layer, and this effect is undesirable in the part itself.

The second reason to use the support is to improve the liquid flow around the part. As the surface of the liquid is cured faster with the improved liquid flow, the settling time is further shortened. In addition, the excess resin is drained more quickly from the finished part, thereby reducing the subsequent processing time.

Also, use a support to fix the section of the part that tends to shake and strengthen the area that is caught or damaged during settling.

Referring now to the drawings and particularly to FIG. 1 of the drawings, a block diagram of an entire stereo lithographic system suitable for implementation of the present invention is shown. The CAD generator 2 and the appropriate interface 3 typically provide a data description of the object to be formed in the PHIGS format to the interface computer 4 via network communication such as Ethernet or the like, And also reduces stress, curl, and distortion in relatively uncomfortable and complex object shapes, and provides resolution, strength and accuracy and speed and reproducibility economics To provide an output vector to increase the output vector. The interface computer 4 slices the CAD data and changes layer thicknesses, rounds and fills the vertices of the polygons, flattening and approximating flat skins, un-facing skins and down- facing skin, scaling and cross hatching, offsetting the vector, and determining the vector order to generate the layer data. This is described in detail in U.S. Patent Application No. 182,830, part of its continuation application No. 269,801, and part of its continuation application No. 331,644. In summary, the boundary vector is used to identify the contour of each section of the object, and the cross-hatch vector is used to illuminate the interior of each section. These vectors are found in the order of boundary, crosshatch, and skin.

The vector data and parameters from the computer 4 are sent to the controller subsystem 5 for operating the stereo lithographic lasers, mirrors, elevators, etc. of the system.

Figures 2 and 3 are flow charts illustrating the basic system of the present invention for generating a three-dimensional object using stereo lithography.

Change to a solid state polymeric plastic by irradiation of ultraviolet light (UV) or other forms of synergistic stimulation, such as reactive chemicals, visible or invisible light, applied electronically, There are many types of chemical substances in liquid state which can be induced to be induced. UV-curable chemicals are currently used in high-speed printing, as adhesives in the coating process of paper and other materials, and in other special areas.

Lithography is a technique for reproducing graphic objects using various techniques. Modern examples include photographic reproduction, xerography, and microlithography used in the production of microelectronics products. Computer generated graphics displayed on a plotter or cathode ray tube is also a form of lithography in the sense that the image is a picture of a computer coded object.

Computer aided design (CAD) and computer aided manufacturing (CAM) are techniques that apply computer capabilities to the design and manufacturing process.

A typical example of CAD can be found in the field of electronic printed circuit board design where a computer and a plotter draft the design content of a printed circuit board given the design parameters as a computer data input. A typical example of a CAM is a numerically controlled milling machine, in which a computer and a milling machine produce metal parts given appropriate programming instructions. Both CAD and CAM are both important and fast-growing technologies.

The main object of the present invention is to make use of the principle of computer generated graphics and combine ultraviolet ray hardening plastic or the like so that CAD and CAM can be executed simultaneously to directly produce a three-dimensional object from a computer command. The present invention, also referred to as stereolithography, can be used to mold models and prototypes at the design stage of product development, or can be used as a manufacturing device or even as an art form. The present invention further improves the development of stereolithography disclosed in U.S. Patent No. 4,575,330, issued March 11, 1986 to Charles W. Hull, one of the inventors of the present invention.

Now more specifically, referring to FIG. 2 of the drawing, a stereolithographic method is schematically illustrated. In the eighth step, CAD or other data representing a three-dimensional object to be formed by the system is typically required to be generated as a digital form. This CAD data usually defines the surface in a polygonal format, that is, a triangle and a normal that is perpendicular to the plane that the triangle forms and that is tilted is currently preferred, and in the presently preferred embodiment of the present invention, (PHIGS: Programmer's Hierarchical Interactive Graphics System: a hierarchical-interactive graphics system for programmers). This standard is described, for example, in the publication Understanding PHIGS published by Megetecco Operation, Template, San Diego, Calif., Which is incorporated herein by reference in its entirety, .

In a ninth step, in accordance with the present invention, the PHIGS data or its equivalents are converted into a modified database for driving a stereolithographic output system in the formation of a three-dimensional object by a unique conversion system. Thus, the information defining the object is specially treated to reduce stress, strain and torsion, and increase the resolution, intensity, and reproduction accuracy.

Step 10 of FIG. 2 requires the generation of individual solid laminates that represent the cross-section of the three-dimensional object to be formed. The eleventh step combines successively formed adjacent laminates to form a desired three-dimensional object programmed into the system to be selective curing.

Therefore, the stereolithographic system of the present invention can be used in a variety of applications including, but not limited to, irradiation of radiation, electron beam or other particle impact, or applied chemicals (by spraying on the mask, Dimensional object by creating a cross-section of an object to be formed on a selected surface of a fluid medium, such as an ultraviolet-curable liquid, that can change its physical state in response to an appropriate synergistic stimulus. A series of adjacent laminates corresponding to a cross-section of a series of adjacent objects are automatically formed and joined together to form the object as a stepped lamina or thin layer, thereby forming a substantially flat, a three-dimensional object is formed and drawn from a sheet-like surface.

The above-described technique shown in FIG. 2 is outlined in more detail in the flowchart of FIG. 3, and in this flowchart again, in the eighth step, the CAD or other data expressing the three- . In the ninth step, the PHIGS data is converted back into a modified database for driving the stereolithographic output system in the formation of a three-dimensional object by a unique conversion system. In a twelfth step, a fluid medium capable of solidifying in response to a predetermined reactive stimulus is placed in a container. In the thirteenth step, in response to the data output from the computer 4 in FIG. 1, the stimulus is applied as a graphic pattern to the specified fluid surface, thereby forming a separate layer of thin solid at the surface, Dimensional object. In practical applications of the present invention, each lamina is a thin lamina, but thick enough to form a cross-section and to have adequate adhesiveness to adhere to an adjacent lamina defining another cross-section of the object to be formed.

In a fourteenth step of FIG. 3, successive adjacent layers, i.e., laminae, are superimposed one upon another to form multiple layers and define the desired three-dimensional object. In a typical practice of the invention, as the fluid medium is cured and a solid material is formed to define a laminar, it is moved away from the working surface of the laminar fluid medium and removed from the new liquid entering the previously formed laminar As the next lamina is formed, each successive lamina is superimposed and bonded to all other lamina laminates (by virtue of the adhesive nature of the cured fluid medium). Of course, as noted above, the present invention also addresses the problems that arise in transitions between vertical and horizontal configurations.

The process of producing such a sectional laminar repeats repeatedly until a complete three-dimensional object is formed. Thereafter, once the object has been removed in the tank, the system is ready to produce another object, which may be the same as the previously formed object, or it may be completely new, formed by modifying the program controlling the stereolithographic system It is possible.

Figures 4 and 5 of the drawings show various devices suitable for implementing the stereolithographic method shown and described by the system and flow diagrams of Figures 1 to 3.

As previously described, stereolithography is a method and apparatus for fabricating solid objects by continuously printing a thin layer of a curable material such as, for example, an ultraviolet curable material, such that one layer overlies another. A solid section of the object is formed on the liquid surface using a programmable movable spot beam of ultraviolet light irradiated onto the surface or layer of the ultraviolet curable liquid. The object is then moved in a programmed manner away from the liquid surface by one layer thickness, after which the next section is formed and the next section is bonded to the immediately preceding layer defining the object. This process continues until a complete object is formed.

In essence, the technique of the present invention can be used to create all sorts of object shapes. In the case of a complex geometry, it can be made easier by using the functions of the computer to help generate programmed commands and send the program signal back to the stereo lithographic object forming subsystem.

There are various types of database in CAD system. As described above, one of them consists of expressing the surface of an object as a mesh composed of triangles (PHIGS). These triangles constitute the entire inner and outer surfaces of the object. This type of CAD representation also includes a unit length normal vector for each triangle. This normal line indicates the direction in which the triangle is moved away from the solid part constituting the outer surface of the triangle. The present invention provides a means for processing such CAD data into layered vector data necessary for forming an object by stereo lithography. A more detailed description of the different vector types is described in U.S. Patent Application No. 182,830 and its part of Continuing Application No. 269,801, and in part of U.S. Patent No. 331,644.

In order for the stereolithography to be successful, the adhesion between one layer and another layer must be good. Therefore, the plastic of any layer must be superimposed on the plastic formed when making the immediately preceding layer. When making a model composed of vertical segments, the plastic formed on a certain layer overlaps precisely on the preformed plastic of the immediately preceding layer, so that the adhesion is good. However, starting from a vertical shape to a horizontal shape, using finite jumps in layer thickness, the plastic eventually reaches a point where it does not touch the plastic formed in the immediately preceding layer , Which can lead to serious adhesion problems. The horizontal surface itself does not cause adhesion problems because it is horizontal so that the entire cross-section is formed on one layer and structural integrity is maintained due to lateral adhesion. The present invention provides a general means of ensuring proper adhesion between layers when providing a method of completely surrounding any surface and a method of reducing stress and torsion in a formed object while at the same time transitioning from vertical to horizontal or from horizontal to vertical sections .

A presently preferred embodiment of a newly improved stereo lithographic system is shown in the vertical cross section of FIG. The container 21 is filled with ultraviolet curable liquid 22 or the like to provide a designated work surface 23. The spot 27 of ultraviolet light is generated on the plane of the surface 23 by the programmable ultraviolet light source 26 or the like. The spots 27 are movable across the surface 23 by movement of mirrors or other optical or mechanical elements (not shown in FIG. 4) used with the light source 26. The position of the spots 27 on the surface 23 is controlled by the computer control system 28. As noted above, the system 28 may be implemented by a generator 20 or the like in a CAD design system to control the CAD data sent to the computerized conversion system 25 in the form of PHIGS format or equivalents thereof And information defining the object is specially processed so as to reduce stress, strain and torsion in the conversion system 25 and increase the resolution, intensity and accuracy of reproduction.

The movable elevator platform 29 in the container 21 can optionally be moved up or down and the position of the platform is controlled by the system 28. As the apparatus is operated, a three-dimensional object 30 is produced by a stepwise build-up of bonded laminates such as members 30a, 30b and 30c.

The surface of the ultraviolet curable liquid 22 is maintained at a constant level in the container 21 and the spot 29 of the ultraviolet light having sufficient illuminance enough to cure the liquid into a solid material, And is moved across the work surface 23 in a programmed manner. As the liquid 22 cures and solid material forms, the elevator platform 29, which was originally directly beneath the surface 23, is moved down by any suitable actuator in a programmed manner. In this way, the initially formed solid material is sent below the surface 23 so that the new liquid 22 flows across the surface 23. A portion of this new liquid is converted to a solid material by a re-programmed ultraviolet light scoop 27, which is adhesively bonded to the underlying material.

This process continues until a complete three-dimensional object 30 is formed. The object 30 is now removed from the container 21, and the device is ready to produce another object. Then, another object may be produced, or a new object may be produced by changing the program of the computer 28.

For example, a curable liquid 22, such as an ultraviolet curable liquid, must have several important properties: (A) it must be cured sufficiently quickly by a conventional ultraviolet light source in order to allow for a practical formation time. (B) The continuous layers must be adhesive to adhere to each other. (C) When the elevator moves the object, the viscous should be low enough so that the new liquid material can flow quickly across the surface. (D) Since the ultraviolet light should be absorbed, the formed film should be suitably thin. (E) After the object is formed, it must be insoluble in the same solvent after it is dissolved in the solvent and solidified so that the ultraviolet curable liquid and the partially cured liquid can be completely washed away from the object. (F) To the maximum extent possible, non-toxic, non-irritating.

The cured material should also have desirable properties once it has become solid. These properties vary, as well as for the conventional use of other plastics materials, depending on the application concerned. The properties to consider include color, texture, strength, electrical properties, flammability, and flexibility. And in many cases the cost of materials will be important.

The UV curable material used in the presently preferred embodiment of the operable stereo lithography (e.g., FIG. 3) is a resin for DeSoTo SLR 800 stereo lithography manufactured by Desoto Inco, Inc., Des Plaines, Ill.

The light source 26 produces a spot 27 of ultraviolet light which is sufficiently small to enable the details of a desired object to be formed, but has sufficient illumination to cure the ultraviolet curing liquid to be used quickly enough to be practical. The light source 26 may be designed to move so that the focused spot 27 moves across the surface 23 of the liquid 2 and is programmed to be on or off. Therefore, as the spot 27 moves, the spot 27 hardens the liquid 22 into a solid, and the chart recording apparatus or the plotter is formed on the surface by a method exactly the same as drawing a pattern on a paper using a pen Draw a solid pattern

The light source 26 in the presently preferred embodiment of stereo lithography is a helium-cadmium ultraviolet laser, such as the Model 4240-N HeCd multimode laser, typically manufactured by Riconix of Sunnyvale, California.

In the system of FIG. 4, the focal spot 27 is kept in a precisely focused state on the fixed focal plane so that the maximum resolution is ensured in forming a thin layer along the work surface. ) At a constant water level and re-supplying the material after the object has been removed. Therefore, it is possible to precisely form a focus so as to provide a high-intensity area on the work surface 23 and to breathe rapidly under low light to limit the depth at which the curing process takes place so that the cross- .

The elevator platform 29 supports and fixes the object to be formed and is used to move it up and down as needed. Typically, after a layer is formed, the object 30 moves past the level of the next layer once to allow the liquid 22 to flow into a momentary void on the remaining surface 23 in the place where the solid is formed , Then move back to the correct level of the next floor and return. The requirement of the elevator platform 29 is that it must be able to move in a programmed manner at an appropriate speed with appropriate precision and be strong enough to handle the weight of the object 30 being formed. It would be useful if the elevator platform position could be manually fine-tuned during the set-up phase and when the object was removed.

The elevator platform 29 may be either mechanical, pneumatic, hydraulic or electric, and may also use optical or electronic feedback for accurate position control. The elevator platform 29 is typically made of glass or aluminum, but any material is acceptable where the cured plastic material can adhere.

A computer controlled pump (not shown) may also be used to keep the liquid level at the work surface 23 constant. A solid rod (not shown) that is immersed in the fluid medium and escapes from the fluid medium as the elevator platform moves deep into the fluid medium, to compensate for volume changes in the fluid and maintain a constant fluid level on the surface 23. [ Or a feedback network known in the art for driving a fluid pump may be used. Alternatively, the light source 26 may be associated with the detected water level 23 so that the correct focus is automatically maintained on the work surface 23. All of these alternatives can be easily implemented by operating the data appropriately in conjunction with the computer control system 28.

FIG. 6 illustrates the overall software architecture of a stereolithography system in which the present invention may be practiced.

In overview, you get the object you want to create in the process part, called SLICE, together with the skeleton or support needed to make it a little harder. These supports are typically generated by the user's CAD. The first thing a slice does is to find the object's contour and its support.

The slice defines each microsection or layer, one at a time, according to a predefined control scheme. The slice creates the boundary of the solid part of the object. For example, if an object is a cavity type, it has an outer surface and an inner surface. In this case, this outline is the most important information. A slice program takes a contour or a series of contours, and if you create an outer skin and an inner skin that do not combine with each other, you can collapse because you have liquid in between. Therefore, in consideration of this point in actual production, the inclination of the triangle (PHIGS) viewed from an arbitrary direction and the previous information are stored, and in a place where one layer has a gentle slope such that it does not touch the top of the next layer, You change the actual part by adding skins between them, solidifying everything in between, or cross hatching between them. The slice performs all of these things and can use some reference tables on the chemical properties of the photopolymer, the intensity of the laser, and related parameters that indicate the duration of exposure of each output vector used to operate the system. These output vectors are organized into groups that can be identified. A group consists of a borderline or outline. The other group consists of cross hatches. Another group consists of skins, which have subgroups of upward and down skins that should be handled slightly differently.

These sub-groups may be subjected to slightly different processes in the process of appropriately managing the output data to form a predetermined object and a support, so that they are revealed in different ways. These vector types are described in more detail in U.S. Patent Application No. 182,830 and its part of Continuing Application No. 269,801, and some of its continuation application No. 331,644.

After the three-dimensional object 30 is formed, the elevator platform 29 is raised and the object is removed from the platform for further processing.

Further, in the practice of the present invention, a plurality of containers 21 may be used, each container containing a different type of curable material that can be automatically selected by the stereo lithographic system. In this regard, plastics having different colors may be provided by various materials, and insulating or conductive materials usable as various layers of electronic products may be provided.

As shown in FIG. 5, an alternative stereolithographic configuration is shown in which the ultraviolet curable liquid 22, etc., floats on the heavy permeable liquid 32 that is immiscible and non-wetting to the curable liquid 22. For example, as the intermediate liquid layer 32, ethylene glycol or heavy water is suitable. In the system of FIG. 4, the three-dimensional object 30 is not moved further down into the fluid medium, as shown in FIG. 3, but rather pulled up from the liquid 22.

The ultraviolet light source 26 of Figure 5 aligns the focus of the spot 27 with the interface between the non-mixable intermediate liquid layer 32 and the liquid layer 22 and the ultraviolet light is supported on the bottom of the container 21 And passes through a suitable ultraviolet transmissive window 33 made of a quartz or the like. Since the curable liquid 22 is supplied in a very thin layer on top of the non-mixable layer 32, ideally an ultra-thin laminar is provided so that the direct layer thickness is limited . Therefore, the area where the formation takes place can be more precisely defined, and some surfaces can be formed more easily than with the system of FIG. 4 using the system of FIG. 5.

In addition, less UV curable liquid 22 is required and it is easier to replace a curable material with another curable material.

A commercial stereo lithographic system may have additional components and subsystems other than those previously shown with respect to the system shown schematically in FIG. For example, a commercial system may also include a frame, a housing, and a control panel. The commercial system must have a means of shielding the operator from excess ultraviolet light or visible light, and there must also be a means of showing the object 30 during the formation of the object. Commercial products will have conventional high voltage safety protection devices and interlocks as well as safety measures to control ozone and toxic vapors. These commercial products must also have a means of effectively shielding sensitive electronic circuits from electromagnetic noise sources.

According to the present invention, component supports are provided by the user in CAD design. The following is a brief description of the support provided in the initial application.

[Requirements of parts support]

A. To separate parts from the platform

1. Cured parts should be easier to remove.

2. The control of the thickness of the first layer should be improved.

3. The holes in the platform create a matching pattern on the part.

B. To improve fluid flow inside and around the part

1. Stabilize the fluid faster.

2. Minimize the dip time.

3. Allow parts to drain faster and better.

C. To fix the free affluent boundary

1. In the case of a sphere, the bed boundary diameter under the equator increases rapidly.

2. The boundary of the bed will drift until the hatch vector is drawn.

a. air current

b. Convective flow of fluid

3. External support is not required on the equator, but may be required internally.

FIG. 7 shows how the support fixes the layer boundaries in place until the cross-hatch vector is drawn.

D. To strengthen other unsupported layer sections

1. Prevention of deformation

a. Sinking

b. Due to the increased weight of the part

2. Anti-curl

a. Layer section can not withstand stress

b. You can use Smalley or support.

FIG. 8 shows a method for preventing deformation of the cantilever beam and the like structure and support of the cantilever beam.

E. To fix the unattached layer sections

1. This layer section will drift during settling.

2. Support depends on which part is built.

3. The support must be in at least one layer below the first section that is not contacted.

FIG. 9 shows how the support attaches to the layer section drifted during settling.

The following is a brief description of web support and is provided for future applications.

[Web Support]

In a preferred embodiment of the present invention, web support is preferred.

A. The most practical form

1. Easy to remove

2. Must not fall through the platform

3. It does not take long to draw

a. Back to back layer boundaries

b. No cross-hatching required

C. No Skin Required

B. You can create a CAD library of common support type.

1. Use similar support for many different parts

2. It is faster to change existing support than to create a new one

Example A: Near the bottom of the solid sphere shown in Figs. 7a and 7b, the layer boundary vectors consist of a circle in which the diameter of each successive layer increases rapidly. Until the cross-hatch vector is drawn, many layer boundaries float freely on the fluid surface. The flow and convection of the fluid can displace them.

This problem is solved by adding a support extending to the equator of the sphere, as shown in Figure 7b. Since the layer boundaries on the equator are directly formed in the cross-vector of the previous layer, they are firmly fixed without further support.

Example B: The first layer of the cantilever beam shown in Figures 8a and 8b (i.e., the unsupported layer boundary) can be permanently deformed by the electrostatic resistance of the fluid when the component is settled. This layer may also be entrained up when the next layer is formed. All of these problems are solved by adding support.

Example C: The first layer of the mug handle shown in Figs. 9a and 9b will not fully adhere at the time of formation and will drift if the part sinks. The support allows the surface on which the handle is made to be secured to the elevator platform or the body of the mug.

[Support Design]

The most practical form of support is the thin vertical web shown in the previous description. The web support is easy to remove during subsequent processing and, if properly designed, will not fall through the holes in the elevator platform. Other forms can provide the necessary support, but there is a drawback that it takes a lot of time to draw.

Generally, the support is designed together as a single CAD file separate from the part file. After the part is designed and oriented for stereo lithography, the relative position of the support for the solid model is set. The object file and the support file are merged in a subsequent stereo lithography process and drawn as one file. Rather than designing specific support for each application, a support library in the CAD is recommended. In either case, the support is designed and attached to the part according to the following guidelines.

Placement: The support should be placed where it is needed to provide a solid foundation from which the part can be created. Also, as described in the previous example, the support must be affixed to fix or reinforce other surfaces.

After the part is subsequently cured and the support is removed, there is usually a ridge on the part surface (the ridge can be cut, scraped or polished). Therefore, if possible, it is necessary to be flexible for aesthetic or functional reasons Avoid placing supports on the surface. The support need not necessarily be attached to the elevator platform, but may be secured to a rigid section of the component.

Spacing: Generally, the supports maintain a sufficiently close spacing so that slight sagging or sagging does not occur. However, if the support is too large, the component production process becomes slow. The web support typically should be spaced about 0.1 to 0.8 inches apart.

Orientation: As shown in FIGS. 10a and 10b, if all web supports for a part are aligned in parallel with each other, the web will fall sideways due to the weight of the part during the creation of the part. Then, the subsequent layers are slightly torn (skewed) relative to the previous layer. By adding somewhat vertical web support to a parallel web, this layer is prevented from being skewed.

Height: In order to prevent bending or tilting and minimize the construction time, web support does not need to be larger than necessary. However, the components are allowed to float at least 0.25 inches above the elevator platform so that drainage and stabilization (mitigation) of the fluid can be optimized. If a long web is needed, a second web perpendicular to the first web should be added for additional support. Viewed in cross-section, the combined support appears as a plus (+) symbol, as shown in FIG.

Length: To minimize the construction time, the support should be of the minimum required length. However, the web support constructed on the platform must be at least 0.65 inches from the location in contact with the platform, otherwise the web support may sag or fall through the hole. The diagonal support start and end portions on the part should be designed as a sub-wall as shown in FIG. 11 so that they do not extend to the corner portions of the part that are difficult to remove.

Width: Web support should be designed as a slab of 1-2 mil CAD thickness. Since the line width drawn by the laser is typically 10 to 20 mils, the actual support becomes significantly thicker than the CAD design. Supports that are designed with a single surface without a CAD volume should be avoided as it will wreak software that creates crosshatching.

Since the beam width compensation algorithm will compensate for the line thickness drawn by the laser, when beam width compensation is used, the support must be designed to be 10-20 millimeters, which is the actual actual width. The beam width compensation is described in further detail in U.S. Patent Application Serial No. 182,830, part of its continuation application No. 269,801, and part of its continuation application No. 331,644.

Attachment: To ensure that the part is firmly attached to the support, the web support must be designed so that the part overlaps on a layer thickness of 2 to 3 layers (typically 40 to 60 mils).

[Common Form of Support]

Straight webs are in the form of very thin rectangles or fins, typically less than 0.02 inches. Straight web support should be defined as a volume rather than a single surface.

A cross web consists of two straight webs intersecting at right angles. Cross web support is stronger than straight web.

A circular web is a hollow tube that is strongly adhered to a target. Circular tubes can be more strongly supported than straight and cross web supports. However, circular webs require many triangles and use a lot of memory.

A triangular web consists of three straight webs that form a triangle. These supports can be used with straight webs that intersect vertices. Triangle web support is stronger than other forms of web support.

[Building support]

As already explained, the support is designed together with a single CAD file that is separate from the part file. These stereolithography (.STL) files are sliced or sectioned before being merged into one file. Slice software and MERGE software features that can be applied to support will be described below. A more detailed description of a commercial embodiment of a slice and merge is provided in U.S. Patent Application No. 182,830, part of its continuation application No. 269,801, and part of its continuation application No. 331,644.

Slicing Support Files: Slices have several options that are normally set to zero when slicing support files. The X, Y, and 60/120 hatch interval values should be set to zero because the web support is thin and no cross hatching is required. For the same reason, the support does not require a skin, so the X and Y skin fill values can also be zero. Since the web support does not require near-flat skins and does not have crosshatching, the minimum surface angle (MSA) and minimum hitch crossing angle (MIA) for the scanned surface should be set to zero.

The slice size and Z gap value selected for the support file must be compatible with the value selected for the part file. That is, the support slice thickness should be the same or equal to the slice thickness of the part file (of the overlap area). Otherwise, it would be impossible to draw lines for the support and the part in the same layer.

Step Period Selection: While forming a wall of web support (1 mil gap), the layer boundaries exposed while drawing the first wall will be reexposed while the second wall is being drawn due to the relatively wide laser linewidth. This effectively increases the step period. Therefore, the step period obtained from the operation curve can be divided into two before it is input.

Layer Control File Editing: The end operator's action needed to form the support is to increase the step period default value for the layer boundary vector forming the first layer of the support using the PREPARE menu option. By doing so, the layer thickness (hardening depth) is increased. Typically, by tripling the default support step cycle period, the first layer of support can be properly attached to the platform.

Another way to create a web support is to create a box with internal cross hatching beneath the part to be cured. In this approach, web support can be generated using slice algorithms that were previously implemented to generate hatch vectors. According to this approach, there is no need to design web support in a CAD / CAM system as described above. The box is created in a separate .STL file, placed in its own .SLI file, and merged into a .SLI file for parts after slicing. In particular, the straight web can be generated by hatching in the X or Y direction. The cruciform web support may be implemented by hatching in the X and Y directions. The triangular web support may be implemented by hatching at 60/120 degrees, or in either the X or Y direction. Also, the hatch interval may be selected from 1/4 to 1 depending on the required support.

An embodiment of a commercial system embodying the present invention, provided by 3D Systems Incorporated of Valencia, California, USA, is illustrated by appended Appendix D, which is a 3D Systems Model SLA-1 stereo It is a training manual for the lithography system.

The new and improved stereo lithography methods and apparatus have many advantages over conventional methods of producing plastic objects. According to this method, there is no need to create a mold production drawing and produce a mold. Designers can work directly with computers and stereo lithography devices, and if the designer is satisfied with the design displayed on the computer's output screen, they can manufacture parts for direct inspection and use the information to define the object , It is possible to reduce the curl and distortion and to increase the resolution, intensity, and reproduction accuracy. If the design needs to be changed, it can easily be done via a computer and another component can be created to verify that it has been changed correctly. When a design of several components with interactive design parameters is required, the method allows all the part designs to be quickly changed, reprocessed, assembled and inspected as a whole, and repeated as necessary, The invention is more useful.

After the design is complete, you can start producing parts soon, avoiding weeks or months between design and production. The final production rate and component cost are similar to the current injection molding unit prices for short-run production, and labor costs are lower than labor costs associated with injection molding. Injection molding is only economical if a large number of identical parts are needed. Stereolithography is particularly useful for shortening the production process because mold preparation is not required and set-up time is minimized. In addition, design variations and custom components can be readily provided using this technique. Stereolithography allows the use of plastic parts in many areas where metal or other material components are currently in use, thanks to the ease of component fabrication. In addition, a plastic model of the object can be provided quickly and economically before it is judged whether to produce a part of expensive metal or other material.

The present invention satisfies the need for a CAD and CAM system that can design and manufacture fast, reliable, accurate, and economical 3D plastic parts and the like in the art.

While particular forms of the invention have been shown and described, it will be appreciated that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, the invention is limited only by the appended claims.

[Appendix D]

3D System Sys

All rights reserved

3D System Sys

Training manual

1988. 4

[Contents]

Foreword ‥‥‥‥

Training schedule ‥‥‥‥‥‥‥‥‥‥

1.0 Overview ‥‥‥‥‥‥‥‥‥‥‥‥‥

1.1 Stereolithography process ‥‥‥‥

1.2 Stereo Lithography System ‥‥‥‥‥‥

2.0 Safety ‥‥‥‥‥‥‥‥‥‥‥‥‥

2.1 Laser Safety ‥‥‥‥‥‥‥‥

2.2 Chemical safety ‥‥‥‥‥‥‥‥

3.0 Stereo Lithography - From start to finish ‥‥

3.1 CAD Design ‥‥‥‥‥‥‥‥

3.2 Orientation and Support ‥‥‥‥‥‥‥

3.3 CAD Interface ‥‥‥‥‥

3.4 Slice computers ‥‥‥‥‥‥

3.5 slices ‥‥‥‥‥‥‥‥‥

3.6 Control computer ‥‥‥‥‥‥‥‥

3.7 Utilities ‥‥‥‥‥‥‥‥‥

3.8 Network ‥‥‥‥‥‥‥‥‥

3.9 merge ‥‥‥‥‥‥‥‥‥

3.10 View (view) ‥‥‥‥‥‥‥‥‥‥

3.11 Preparation ‥‥‥‥‥‥‥‥‥

3.12 Construction ‥‥‥‥‥‥‥‥‥

3.13 Follow-Up Process ‥‥‥‥‥‥‥‥‥

3.14 Checklist ‥‥‥‥‥‥‥‥‥‥

4.0 Troubleshooting Techniques ‥‥‥‥‥

4.1 Limitations of Stereo Lithography

4.2 Part creation problems and solutions. .

5.0 References ‥‥‥‥‥‥‥‥‥

5.1 Laser theory

5.2 Chemical theory of stereolithography ‥‥‥‥

5.3 bullet, banhotop and work curve

Term explanation ‥‥‥‥‥‥‥‥‥

[preface]

[Purpose and scope]

This training manual covers what is needed to make a stereo lithography.

The content is divided into five sections, each describing the different properties of stereolithography.

Section 1: Overview of Stereolithography Processing and Hardware and Software.

Section 2 deals with laser and chemical safety.

Section 3: We describe how to assemble detailed parts by dividing them into 13 bars according to the order of assembly. Some of these sections are divided into basic sections and intermediate sections as necessary.

Section 4 discusses the limitations of stereolithography and how to deal with common component manufacturing problems.

Section 5: This is about background knowledge such as laser, chemistry, and work curve. Training schedules and glossary terms for stereolithography are also included in this manual, which are color-coded to aid reader's quick reference. The SLA-1 training plan is a five-day course. During the first two days, we discussed the production process of the basic parts and the operation of the SLA-1 to produce simple parts. For the remaining three days, the SLA-1, which produces more complex parts, is progressive in its handling of intermediate content. At the end of this 5 day coach, you will be able to operate the SLA-1 to produce a wide variety of parts directly from CAD data.

Abbreviations

CAD Computer-aided design or design

CFM ft ³ / min

DOS disk operating system

Minimum intersection angle (θ) between MIA hatches

Minimum surface angle of the MSA scanned polyhedron

MSDS Material Safety Data Sheet

NIOSH National Employment Safety and Health Substrate

PCA post curing device

RHR clockwise (right-handed) rule

SEA stereolithography device

UV UV

[sign]

^ Space (Space)

Enter key

Control / Break key

[File extension type]

· BAT batch file · R range file

· EXE executable file · SLI slice file

· L batch file · STL CAD stereolithography file

· MAT data file · U11 slice option file

· PRM parameter file · V-vector file

[Terms]

Parts: Combined Objectives and Support

Object: CAD model (binder of detail parts)

Support: Support structure where the object is generated

[Training Schedule]

Day 1: Introduction to classes, training schedule, overview safety rules,

Wrap 1-Parts Production 1

Stereolithography - from start to finish

CAD design, orientation and support, CAD interface, slice computer, slice-basic

Wrap 2-slice

2 Date: Stereolithography - from start to finish (continued from day 1) Control computer, utility - basic, lab 2 - utility

Network - Basic

Lap 2-Network

merge

Lap 2-Mersey

Preparation - BASIC

Lab 2 - Preparation

Generation - Basic

Lab 2 - Create

Subsequent Process

Lap 2-Follow-Up Process

check list

Day 3: Stereolithography - from its start to its end (continued from day 2)

Slice - Intermediate

Lap 3 - Slice

Utility - Intermediate

Lab 3 - Utilities

network

Lab 3 - Network

View

Lap 3-View

Preparation - Intermediate

Lab 3 - Preparation

Generation - Intermediate

Lap 3 - Create

Day 4: Bullet, Banjotops and work curve

Data file

Lap 4 - Creating Parts 4

Group discussion

Day 5: Troubleshooting Techniques

Problems and solutions for creating parts

Discussion among students

Installation of stereo lithography, customer support

Training assessment

Terminator

Section 1

[Overview]

Stereolithography is a three-dimensional (three-dimensional) printing process that accurately reproduces CAD solid or surface models from CAD data. This process prints or draws the cross-section of the model on the surface of the photocurable liquefied plastic using a movable laser beam directed by a computer. Once one section is drawn, it is lowered by the elevator by a depth of one layer to be immersed in the liquefied plastic tank, and another section is drawn directly on top of the first section. Due to the nature of liquefied plastics, each layer is bonded to the end. This process is repeated until the model of the stereolithography is finished in a three-dimensional shape upward from its bottom side. In this way, stereolithography reproduces models designed in CAD in a much shorter time than conventional models using conventional tools. The work that can take days, weeks, or months in the current method is only possible in a few hours using stereo lithography.

Stereolithography can be used for a variety of applications, such as;

● Design Engineering

Automotive industry

Atmosphere and space

Commercial

Medical field

● Manufacturing Engineering

● Architectural design

● Other scientific fields

.

1.1 Stereo Lithography Process

The process of stereolithography is done through nine basic processes in three main devices (see also Chapter 12)

[CAD system]

CAD Design (Level 1)

The part is designed as a solid or flat model on a CAD system without special reference to stereolithography.

Orientation and support (Step 2)

The CAD model is fitted in a three-dimensional space (within the CAD system) for stereolithography.

The base, or support, is designed to hold and support the component while the component is being created (image configuration on the screen).

CAD interface (3 levels)

The CAD model is processed through an interface to generate a file formatted for stereo lithography. This .STL file is a file that contains information about all surfaces of the CAD design model. The interface can be purchased through a CAD supplier.

[Stereo Lithography Apparatus]

Slice (Step 4)

A stereolithography file (.STL) representing a three-dimensional object is sectioned on a slice computer to create a layer of thickness desired by the user.

Network (Step 5)

The sliced file is transferred from the slice computer to the control computer via Ethernet or diskette.

Merge (Step 6)

The sliced files for the part (i. E., All files for the support and the part itself) are combined and reformatted for use in operating the SLA-1.

Preparation (Step 7)

The user specifies parameters for component creation to match the phase and end use of each part.

Create (Step 8)

The parts are focussed on the surface of the photosensitive resin with the focus of the laser beam, and the resin in the part where the laser beam hits is solidified, and the shape is formed one layer at each irradiation. The first layer (bottom layer) is bonded to a horizontal platform located directly below the resin surface. The platform is attached to the elevator and falls down by one layer under the control of the computer. Each time one layer is created, the platform is lowered by one layer to the bottom of the resin so that the next section can be formed on the resin layer of the surface. Stopping a moment after the elevator descends by one layer is to ensure the time the surface of the resin is leveled. Since the resin is sticky, the next section produced is firmly adhered to the first section produced. This process is repeated until a stereoscopic object is completed. The excess resin left in the water tank without being irradiated with the laser beam is used for the next part production. Thus, there is almost no waste of resin.

[Subsequent curing device]

Subsequent steps (step 9)

The parts are drained to remove the excess resin, the ultraviolet rays are radiated to complete the polymerization process, and then the support is removed. If necessary, it can be polished, bonded to a working model, painted, and so on.

1.2 Stereolithography system (see also Figures 13a-13b)

● Stereo lithography equipment

● Subsequent curing device

[Stereo Lithography Apparatus]

The major components of the SLA-1 are as follows (see also Figure 14):

● Control computer

● Laser and optical systems

Process chamber

● Control panel

● Slice computer

[Control computer]

Every stereo lithography process from network to creation takes place on the control computer. The computer is equipped with a menu program to facilitate program and parameter selection.

● 286 computers with MSDOS (single use, single task)

● Monochrome terminal

● 40MB hard disk

● 36-38 MB of disk space

● Ethernet interface

[Laser and optical systems]

The SLA-1 laser and optical system are mounted directly on the process chamber. These components generate a laser beam under computer control and irradiate the surface of the liquefied resin. Used in SLA-1 are helium-cadmium (HeCd) and multi-mode ultraviolet lasers.

The output power of the laser beam is adjustable and has an output power of 15 milliwatts at a wavelength of 325 nanometers. As shown in FIG. 15, the SLA-1 optical system consists of a shutter assembly, two orthogonal beam-turning mirrors, a beam amplifier, and X-Y movable mirrors mounted on the lens. A 2 inch diameter precision lens is intended to allow the laser beam to enter the chamber while optical components are isolated from the chamber environment.

A solenoid-type shutter operates to shut off the laser beam when the interlock switch is activated. The interlock switch monitors the removal of the laser beam and the opening of the lid and process chamber of the lens.

The orthogonal beam inversion mirror is specially coated to reflect only the beam of wavelength 325 nm with high efficiency and not to reflect beams of other wavelengths. The first inversion mirror reflects the beam from the laser to the entrance aperture of the beam amplifier. The second mirror reflects the laser beam from the beam amplifier exit aperture to a dynamic mirror.

At this time, the unchanged laser beam is scattered with a small distance. The laser beam used in stereolithography requires a high focal point because the higher the focusing intensity, the higher the output and the more reliable or faster bonding of the plastic. The beam amplifier amplifies the diverging laser beam by four times the diameter of the inlet of the amplifier, and focuses the beam again to converge the beam to the surface of the resin at one point.

A high-speed moving mirror deflects the laser beam under the control of a computer to form a vector on the resin surface. Like the beam inversion mirror, the movable mirror has high reflectivity and is designed to reflect mainly only the beam of 325 nm wavelength and to radiate beams of other wavelengths.

[Process chamber]

The process chamber, controlled according to ambient conditions, consists of an elevator and a platform, a resin tank and a profiler, and functions to generate the final parts of the stereolithography.

The chamber is designed to maintain user safety and uniform working conditions. Air is circulated and filtered through the activated carbon. In addition, the upper part of the chamber is equipped with a light source that illuminates the resin tank and the resin surface. The interlock on the access door activates the shutter to block the laser beam when the door is opened. The transparent acrylic door prevents the worker from having ultraviolet rays.

The elevator rises or falls under the control of the computer, and the platform supports the part while the part is being created.

The resin tank is 9 inches tall and is mounted on a guide line where the elevator and platform in the chamber are aligned. The overflow system in the tank controls the remaining resin to flow into the processing vessel to maintain a constant amount of resin at all times.

Two beam profilers are placed in the process chamber, each placed on both sides of the resin bath. The beam profiler always measures laser output and focusing intensity under the control of a computer.

[Control Panel]

The SLA-1 control panel includes the following components:

Power switch: Switches main power to laser, power, process chamber, and control computer

Oven light switch: A switch that turns on and off the top lighting of the process chamber.

Laser On Indicator: An indicator that indicates the irradiation of the laser beam.

Shutter On Indicator: An indicator that indicates the opening of the shutter during irradiation of the laser needle.

[Slice computer]

The slice computer generates an .SLI file from the .STL file of the cross section.

● 386 computers with UNIX (multi-user processing, multi-tasking)

● Monochrome terminal

● 70MB hard disk

● _ MB available disk space

● Ethernet interface

[Subsequent hardening device (see Fig. 16)]

A subsequent curing device (PCA) is used to cure the parts made with SLA-1. The work is simply to expose the parts to ultraviolet rays in the enclosed chamber with the drain, and the PCA can accommodate all parts up to 12 inches in length, height and height. The main components are as follows.

• A reflector and three 400-watt inert metal ultraviolet lamps located in the chamber for optimal curing. The working life should be 750 hours or more.

● Rotating table that makes one revolution per minute for uniform curing

● Two doors for inserting and removing parts (one on the top of the chamber and one on the front of the chamber). Both doors are interlocked to stop the ultraviolet lamp and turntable when both doors are open, and a window is provided to shut off the ultraviolet rays when the operator observes the parts.

● A fan that can cool and ventilate 240 ft / min.

● Control panel with power switch and timer.

Section 2

[safety]

2.1 Laser safety

[Characteristics of safety]

The SLA-1 is designed as a Class 1 laser device, which means that under normal operation the laser beam does not leak out of the device. The safety characteristics of the other SLA-1 are as follows.

• When the interlock circuit is activated, interlock the laser and optical cover, and the door of the process chamber that activates the shutters to block the laser beam.

● Control panel lamp to indicate if the laser is running or the interlock circuit is active

Information label for warnings and safety

The SLA-1 has the following laser safety label. The attachment position of the tag is shown in Figs. 17a to 17b.

ID / proof mark

Two proof labels demonstrate conformity to the CFR laser safety application standard and provide usage power and identification data.

Interlock protective cover label

Three interlock protective cover labels are affixed near the three interlock switches.

This label meets the criterion applicable to interlocks that are class IIIb and may fail.

Non-interlock protective cover label

One unlocked protective cover label is affixed to the visible protective housing when the laser cover is removed. This label meets the requirements of the uninterrupted IIb class.

Safety caution

There is a risk of exposure to harmful, invisible laser radiation when operating, adjusting, or working in any way that is not covered by this manual. If the SLA-1 is operated normally, the laser beam does not harm the user. However, the possibility of exposure to a helium-cadmium laser with a force of up to 100 nm at a wavelength of 325 nm is likely to occur if interlocks fail due to any reason (including the use of SLA-1 as described in this manual) have. If you work on the training manual of the SLA-1 and the interlock fails, immediately wear a UV shield and avoid direct exposure to the laser beam. Also, never look directly at the laser beam or look at the laser beam that is reflected from a mirror or other flashing surface.

2.2 Chemical Safety

[Safety instructions]

Photopolymers used in stereolithography include multifunctional acrylic compounds that may be harmful if handled incorrectly. Workers involved in the handling of chemicals must obtain guidance in the Material Safety Data Sheets (MSDS) and refer them to their work. Below is a summary of safety guidelines for the DeSolite SLR 800 resin.

UV curable resins may cause eye and skin burns. Repeated or prolonged exposure of the resin to the skin may cause abnormal sensations. In addition, resin vapors may also be harmful.

● When handling the resin, the safety shield with side protection plate is applied.

● Wear chemical resistant gloves when handling resin and wear protection.

● When you are finished, thoroughly wash your body thoroughly before eating, smoking or going to the bathroom.

● Ensure proper ventilation. Pay particular attention not to inhale resin vapors or mist.

● Keep away heat, electric sparks, and flames. Avoid exposure to sunlight or fluorescent light. A closed plastic container may rupture or explode if exposed to excessive heat.

Use the National Fire Protection Association's Class B fire extinguisher (carbon dioxide powder extinguisher, foam extinguisher)

• Wear respirator approved by the National Occupational Safety and Health Administration (NIOSH) and ensure proper ventilation when grinding or cutting hardened parts

● Dispose of the resin as prescribed. There should be no reuse of the empty plastic cask.

First Aid Guide

[Skin contact]

Wash thoroughly with water and soap. Remove contaminated clothing and shoes immediately. If skin irritation persists, see your doctor immediately. Wash clothing before reuse and dispose of contaminated leather shoes or other equipment.

[Eye contact]

After intensive cleaning with large amounts of water for 15 minutes, do not show sunlight, fluorescent lights or other ultraviolet rays, and see the doctor.

[Inhalation]

Move patient to fresh air to ventilate or take prescribed CPR measures. If breathing is difficult, give oxygen breathing and see to doctor.

Section 3

[Stereolithography - from start to finish]

This section is divided into 13 sections, detailing the process of making parts for stereo lithography. Each measure contains a basic chapter that explains the start command and the workflow, and some of the bars contain intermediate chapters that explain the assembly of more complex parts.

3.1 CAD Design

3.2 Orientation and Support

3.3 CAD Interface

3.4 Slice Computer

3.5 slices

3.6 Control computer

3.7 Utilities

3.8 Network.

3.9 Merge

3.10 Observation

3.11 Preparation

3.12 Create

3.13 Follow-Up Process

We will use the same parts (see Figure 18) as an example of a basic chapter for each measure. Students will assemble these parts during the first two days of training, then study intermediate materials and then make more complex parts. At the end of this section, checklists are provided to assemble the parts.

3.1 CAD Design

[surface]

The object should be represented by a closed surface that clearly defines the clogged volume. In other words, the model data must specify what is not inside and inside the solid matter of the object. So that all the horizontal sections can be composed of closed curves that clearly separate the interior and exterior of the object.

[CAD Resolution]

When an object (e.g., a sphere or a cylinder) having a curved surface is to be generated, it is to be noted that the curved surface is formed by a plurality of regular or regular polygons. The larger the number of faces and angles of a polyhedron or polygon, the more approximate to the curved surface, and the more smoothly curved surface can be made. However, the larger the number of faces or angles, the longer the time required for slicing and, consequently, the size of the slice file. In general, use the lowest acceptable resolution.

[Wall thickness]

The minimum recommended wall thickness for curved objects is 0.020 inches. Smaller wall thicknesses are only possible under special conditions. The absolute minimum thickness of the wall is twice the laser beam width.

3.2 Orientation and Support

[Orientation of CAD model]

For processing with stereo lithography, the CAD part must be in the positive space of the X, Y, Z Cartesian coordinate system. Then, it should be oriented according to the following conditions.

● The distance between the part and CAD coordinate origin should be minimized.

• The height of the support structure should be minimized.

The part should be located at least 0.25 inches above the platform for efficient drainage. However, if the support is too high, it takes a long time to make and may be distorted due to the weight of the parts that are increasing during the production of the parts.

● The height of the object should be minimized. This reduces the number of layers to be produced, thus shortening the working time.

• Optimize component drainage.

● Minimize the number of slopes. These surfaces are formed by superimposing the layers, so that the thickness of each layer becomes the step height, and the surface becomes a stepped step shape.

• Smooth or aesthetically pleasing surfaces should be vertical or upward horizontal (horizontal and upwards are softer than downward).

● Place parts so that the volume of resin is minimized as they are created. The longer the time required to fix the liquefied resin, the longer the time required to level the resin surface after descending the layer, and the longer the time required for component creation.

● Ensure that important circular cross-sections are placed on the X-Y plane. Higher resolutions are possible in the X-Y plane.

● Verify that the part is acceptable for the resin tank. If the part is too large, it can be split up and created several times before it can be recombined in a subsequent process.

The importance of each element is determined according to the purpose of manufacturing the part.

[support]

Objects of stereo lithography are created on the support, not directly on the platform of the elevator. The main reasons for using support are:

• Separate objects from the platform. this is

- The support can be easily removed during subsequent processing.

Even if the platform is warped or improperly installed, the first layer of the object can maintain a uniform thickness.

- Extra resin drains quickly through the platform. This reduces the time required to make the part because the resin surface becomes flat more quickly after the part is locked. Also, if excess resin is drained quickly from the finished part, the time required for subsequent processing is shortened.

• Firmly fasten the part to the platform or other component section.

● Prevent torsion or damage during settling.

Usual Form of Support

Straight web: It is a very thin rectangular or fin shaped protrusion, typically less than 0.002 inches thick. The straight web should be defined as a volume, not a plane.

Cross Web: A web consisting of two straight webs that are orthogonal to each other. Cross web is better than straight web.

Circular web: A tube-shaped web that supports objects strongly. Circular webs can handle larger loads than straight webs or cross webs. However, this requires more triangles and increases memory requirements.

Triangular web: Consists of three straight webs forming a triangle. This web can also be used in connection with straight webs with vertices. Triangular webs have strong bearing capacity for objects than any other web.

[Example 1]

Near the bottom of the solid sphere (see also Figures 7a-7b), the bed boundary vector consists of circles having diameters increasing rapidly for each successive layer. Most layer boundaries float freely on the resin surface until another vector is drawn. The layer boundaries can deviate from position due to the flow of air or convection in the liquid.

As can be seen, this problem can be overcome by adding a support that extends to the equator of the sphere. Note that the layer boundary above the equator is directly formed on the cross hatch vector of the previous layer and is firmly anchored without further support.

[Example 2]

The first layer of the cantilevered beam (see also Figs. 8a-8b) can be permanently deformed due to the electrostatic resistance of the liquid when the part is settled. Further, when the next layer is formed, there is a possibility that the layer is warped upward. All of this can be solved by attaching a support.

[Example 3]

Once the part is formed, the first layer of the mug handle (Figs. 9a-9b) will be completely detached and the layer will drift if the part is settled. The support provides a plane fixed to the elevator platform or mug body so that the handle can be made thereon.

[Support creation]

caution:

● The support must be fully contained within the positive area of the CAD space.

• The bottom support should overlap the bottom layer of the object about 0.040 to 0.060 inches (usually 2-3 layers thick). It is a way to solidify the binding between the object and the support.

● In case of side support, it also overlaps with the object to secure the supporting force.

In general, the support is designed together with one CAD file that is distinct from the file of the object. After the object is designed and oriented for stereo lithography, a support is placed for the object (the object and the support file are merged into a single file in a subsequent stereo lithography process). By using the support file library included in the CAD system, the need to design individual supports for each object is reduced. In any case, the support shall be designed and attached to the object in accordance with the following guidelines.

Positioning: The support should be positioned so that it can provide a solid foundation from which the object can be created. This includes corners and corners. Also, as described in the previous example, it should be placed in a direction to fix or support the other surface. If possible, avoid placing supports on surfaces that need to be smoothly molded for aesthetic or functional reasons. After the parts are subsequently cured to remove the supports, traces of traces remain on the surface of the part (however, these traces can be cut and polished or rubbed off). The support should be attached to the strongest part of the part as well as the platform of the elevator.

Batch Spacing: The spacing between supports is usually 0.1-0.8 inches. Generally, the support is arranged at a sufficiently dense spacing so as not to generate significant irritation.

However, it should be kept in mind that an excessive number of sup- porting devices will require more time for parts production.

Orientation: Use a cross web to prevent twisting of the layer. As shown in FIGS. 10a-10b, if the strong web supports for the parts are arranged in parallel with one another, the webs can be tilted sideways due to the weight of the parts while the parts are being produced. Then, the subsequent layers are also slightly offset relative to the previous layer.

Height: The support must support the part at least 0.25 inches above the elevator platform to facilitate numerical drainage and surface watering during operation. The support should not be higher than required to prevent objects from bending or tilting and to minimize drawing time. If high support is required, the support must be reinforced using a cross, round or triangular web.

Width: The width of the supports should be at least 0.65 inches from where they touch the platform. Otherwise, the support may tip or fall into the drain hole of the platform. However, in order to minimize drawing preparation time, the support width should not be too large and it must be as necessary. As shown in FIG. 11, the inclined supports starting from the body of the component and ending in the body should be designed as buttresses, extending to the corners of the component so as not to be difficult to remove.

Thickness: The thickness of the support should be designed to be as small as possible (the thickness of the web support should be 1 mm). Since the line thickness of the laser is usually 10-20 millimeters inches, the actual support is significantly thicker than in CAD design. Supports designed with a single surface without CAD volume are not acceptable.

Attachment: In order to ensure that the object is firmly attached to the support, it is desirable to superimpose the objects in the vertical direction about 0.040-0.60 inches (usually 2-3 layers thick) with each other during design.

3.3 CAD Interface

[Theory of tessellation]

Most CAD and solid modeling templates represent the surface of a part as a set of triangles. Triangles are the simplest multivariate to calculate, and if you use a large enough number, you can approximate almost any surface.

Besides triangles, the easiest geometric figure is square. The most difficult thing to interpret is the curve. As shown in FIG. 19, the rectangle may be formed as two triangles opposite to the opposite sides. On the other hand, if it is a curved surface, it can be approximated only by a huge number of triangles. SLA-1 can produce accurate rounds and other surfaces by processing up to 14,000 triangles per stereo lithography (.STL) file.

[Classification of triangle]

As shown in FIG. 20, the triangles of the CAD are classified in the form of flat (horizontal), near-flat and steep (vertical or vertical approximation) for the purpose of using the stereolithography. The simplified car roof consists of a set of flat triangles. The hood and the trunk are made of an approximate flat triangle. The front, side, and rear of the car are the components of the steep triangles.

[.STL format file]

The .STL file required to be input to the slice consists of outliers (from solid) triangles with unit normals. This format sets the X, Y, and Z coordinates of the vertices and unit normals of each triangle. Interface devices for deriving .STL files are supplied by CAD vendors.

The configuration of the .STL file can be ASCII or binary formatted code. Binary code is preferable considering the efficiency of operation, disk space, and the like. ASCII is used only occasionally, because it is easy to debug the interface.

3.4 Slice Computer

[survey]

The stereo lithography file is input to a slice computer and sectioned by a slice program. The sliced file is transferred to the control computer for further processing. All files are transferred via an Ethernet or floppy diskette.

[Using UNIX]

UNIX is a multi-task, multi-user functional operating system. All commands are entered in lower case. The slice computer runs the Bourne shell.

[start]

Login: Enter the user ID at the login prompt.

Password: Enter the password. The password is not displayed on the screen.

UNIX prompt: When you see the UNIX prompt, hit the UNIX command or run the slide program.

Welcome to the UNIX Operating System

$

dosget: Used to copy files from a DOS-formatted diskette to a working directory. Specify -a for ASCII files, or -b for binary files.

Note: Slice computers do not require file type (ASCII or binary) specification. The default value is ASCII.

Copying files and Logoff

dosput: Used to copy files from the working directory to a diskette in DOS format.

Abort: Use the Enter key or the Delete key to end the slider.

UNIX commands

UNIX is a very powerful operating system with numerous commands and options. However, if the command is used for routine tasks, it will suffice to be listed below. Other commands should refer to UNIX resources.

cat: Used to display files on the screen. For example, to display newfile.ext on the screen

.

cd: Use cd (directory switch) when moving from one directory to another. For example, to go from the home directory to the newdir directory,

.

If you want to come back to your home directory, $ cd .

cp: Used to copy files. If you want to create a file named newfile exactly like oldfile that already exists in the current directory

.

df: Displays the number of remaining disk blocks.

.

du: Summarizes disk usage.

Files and subdirectories in the ls: directory are listed alphabetically. If the directory has no contents, only the $ prompt is displayed.

ls accepts a filename or directory name as an argument. If you use a file name, it will be listed on the screen if the file is in the directory.

If you specify a directory, all files in the directory will be listed.

There are several options that can be used with the ls command, the most useful of which are:

# ls ^ -1: Indicates the mode, number of links, owner, group, file size, and last modification time for each file in the directory.

mv: Used to change the name without changing the contents of the file or directory. For example, if you want to rename newfile to oldfile

.

pwd: To display the contents of the current working directory on the screen

.

rm: Use rm (remove) to remove files from the directory. For example, if you remove newfile from the current directory

.

who am: If you want to know the name of the current worker, use who am i

.

3.5 slices

[Overview (Article 21 Accession)]

As shown in FIG. 21, the slice is divided into three-dimensional (.STL) files of stereo lithography into layered sections on an XY plane, each of which is placed next to the next to create a three- Create a slice (.STL) file to be configured.

[General Information]

Log on directly from the slice computer or log on to the control computer using the remote user (REMOTE USER). Run the slice at the UNIX prompt ($). The next step is to change the default options and enter special parameters as needed. These options directly control slicing and have a significant impact on the parts that are later created in stereo lithography. These options (such as parameters) can be saved in an options file (.STL) for later use in the same or similar tasks. The final step is to create a slice (.STL) file by slicing the STL file into slice options.

[Floor boundary, cross hatch and skin fill (see Figure 22)]

Layer Border: The layer boundary vector defines the boundary surface.

Crosshatch: The cross hatch vector is created in the slice file by the slice to partially support and adhere the resin between the layer boundaries. The spacing between the crosshatch and the type used is chosen prior to executing the slice.

Skin fill: The horizontal (top and bottom) faces consist of a contiguous series of parallel vectors that form the skin shape. The layer between the skins is generally cross-hatched to reinforce the bearing capacity.

[Layer thickness]

The layer thickness corresponds to the vertical resolution of the part as a slice parameter that allows the user to select the thickness of the layer and vary the thickness. The thinner the layer, the higher the accuracy of the part and the resolution of the vertical (Z) axis. The precision and resolution of the vertical axis are limited to the thickness of one layer.

The tilted (approximate flat) surface is approximated by smaller horizontal and vertical planes that appear stepwise. The thickness of the selected layer is one step height of the slope. The gap between layer boundaries is filled with skin fill. Other areas may cross-hatch if needed. Reducing the layer thickness of the approximate flat area can result in a more smooth surface because each step height is reduced.

The thicker layer can be used to strengthen the part and in some cases reduce the time required to create the part. However, since the laser must be projected at a slower speed onto the resin surface in order to draw a thick layer, the time saved by making thicker and thus the number of layers reduced is partially offset by the reduction of the drawing speed.

[Vector block]

The slice (program) generates a vector block for various two-point vectors. The identification of blocks follows the mnemonic rule as follows.

[Slice resolution]

The slice resolution moves the .STL file from CAD space to Slice space by specifying the number of slice units included in each CAD unit.

Slice resolution = Slice Number of units / CAD unit

[Slice main menu]

Type of command

Alter: Changing standard slicing parameters

Extra: Selects other parameters that are not in the Alter menu. These other parameters specify the vertical axis for component creation.

(Default) Slice the part along the Z axis.

-Slide the part along the X axis.

-Slide the part along the Y-axis.

Save: Stores the options displayed on the screen, the thickness table of the variable layer in the current option file, and other parameters.

DoSlice: Execute the slice program using the current option.

Quit: Terminate the slice. Quit does not save the options file (you must first SAVE it).

[Alter Menu]

Database file name: Specify whether the .STL file to be sliced and its ASCII or binary code. Enter only the file name. The extension .STL is automatically granted.

Resolution: Divide the CAD unit into smaller slices, which are necessary to create a smaller, three-dimensional grid. Thus, if the CAD model is designed in inches and the resolution is set to 1000, each inch of the part is divided into 1000 slice units, each with a length of 0.001 inch.

caution :

● The higher the resolution, the smaller the distortion of the triangle and the less the crosshatch error.

• All files that make up a single part (all support and object files) must be sliced to the same resolution.

● The largest X, Y, Z axis coordinates of the CAD model are determined as the maximum allowable value for the slice resolution.

(Maximum length) * The total number of slices is 65,535 or less.

● Use a non-unique number (eg, l000,2000,5000, etc.)

Layer Thickness: Determines the vertical slice thickness in CAD units. (Thickness of the layer is later displayed in both CAD units and slice units, but input must be in CAD units.)

The thickness of the layer may be fixed for the entire file (i. E., The same layer thickness is assigned to all layers) (different thicknesses for each group of layers). The thickness of the most commonly used layer is 0.002 to 0.030 inches.

For example, if you want to make a part of a layer that is 0.01 inches thick, type .01. Then, the screen automatically displays the layer thickness of the slice unit under the heading SLICE UNIT. The maximum number of layers that can be used is 16,384 (this corresponds to slicing an 8.0 inch component into a 0.0005 inch thick layer).

Hatch interval: The options in (4), (5), and (6) specify the vertical distance between the adjacent hatch vectors shown in parallel, drawn in parallel to the X and Y axes or tilted 60 or 120 degrees from the X axis, in CAD units. do.

caution :

The most commonly used hatch interval values are 0.05-0.10 inches.

● Give a value of 0 for web support (web support is designed with vertical surfaces facing each other, so crosshatch values are unnecessary). A value of 0 means that no crosshatch occurs.

• X and Y cross hatches are typically used simultaneously to form a square grid.

• X and 60/120 cross hatches tend to be used most often because the structure of the part is more robust than when the X or Y cross hatch alone is used.

Pitch spacing: Options (7) and (8) specify the vertical distance in CAD units between skin vectors drawn parallel to the X or Y axis respectively.

caution :

• The most commonly used fill spacing is 0.001-O.004 inches.

● If X and Y fill are used together at the same time, they are not used at the same time because the surface is stressed and can be deflected.

● Use a value of 0 for support.

Output file name: Slice This is the file name assigned to the output file.

Stop: Pass control to main menu program.

Work Order (Wrap 2 - Slice)

before start

Transfer the .STL file to the slice computer.

● Log on to UNIX.

Step 1) At the UNIX prompt, run the slice program and enter the object file name.

Step 2)

In the slice main menu, press A to change the standard option.

Step 3) Current object: CAM_PART

In the Alter menu, update or confirm the following options:

Press Q to return to the slice main menu.

Step 4) Press E to set the other parameters and enter -y.

Step 5) Press S to save the options file as cam_part.UII.

Step 6)

From the slice main menu, press D to slice the cam_part file.

Step 7)

When the slice is terminated, To return to the slice main menu.

Step 8) At the slice main menu, press A to change the standard option for the support file (cam_bass).

Step 9) In the alter menu, update the options below.

The values of hatch, skin fill, and MSA (minimum surface angle of the scanned polyhedron) are set to 0 (options (4) - (9)).

Step 10) Press E, then set the other parameters to -y.

Step 11) Press S to save the options file as cam_bass.UII.

Step 12) From the slice main menu, press D to slice the cam_bass file.

Step 13) At the slice main menu, press Q to end the slice program.

You are then returned to the UNIX prompt.

[Intermediate Topics]

[Slice main menu]

Load: Load another file. The previously listed options on the screen are not automatically saved (be sure to use the SAVE command). Using the LOAD command is equivalent to terminating the slice program and re-entering the new file into the slice.

Write: Writes the option to another object's option file.

Copy: Copies the option file of the saved object to the current option file.

The COPY command reduces the effort of retyping options that are similar to the values entered during the previous run.

[Change menu]

Variable layer thickness

Since the layer thickness can be changed, a layer set (range) in which the layer thickness can be individually specified can be created in the file.

The thin layer is usually used in the following cases.

● Minimize the stepped traces on the inclined surface

• A thick layer is often used to reinforce unsupported areas or to create a stronger and harder layer to improve the accuracy of very important vertical dimensions and fine details of the part.

[Layer thickness command]

A: Add a new Z level to the table. The Z level specifies the vertical dimension to start slicing to the specified thickness. Both the starting dimension and the layer thickness are entered in CAD units. Slicing will continue at this interval until another Z level is specified. The first (lowest) Z level should start at or below the bottom of the object to be sliced.

D: Delete the Z level from the table.

S: Save the table and pass control to the alter menu.

Q: I do not save the table and go back to the alter menu.

H: Outputs a help menu similar to the above-mentioned counterpart.

[MSA]

The SLICE parameter MSA (minimum surface angle of the scanned polyhedron) defines the critical angle at which the triangle classification changes from approximate flat to steep. As shown in FIG. 23, the approximate flat triangle has an angle (relative to the horizontal plane) greater than zero and has an angle smaller than or greater than the MSA. The steep triangles are arranged at angles less than 90 but larger than the MSA.

caution :

● Triangles with smaller slopes than MSA are classified as approximate flat. In the case of this triangle, the slice creates an approximate flat skin to fill the gaps between adjacent layer boundaries. If the MSA angle is too large, the slice will generate more skin vectors than necessary, resulting in longer execution time and larger file size. Too small an MSA angle results in the liquid being drained out of the wall of the object due to the gap of the finished part.

● The correct MSA value will vary depending on the layer thickness used.

The recommended MSA values are:

● Give Web support a value of zero.

[MIA]

This allows you to remove specific hatch vectors that can cause problems in part creation. This is an advanced option, so please consult the application engineer of the 3D system.

Work Order (Wrap 3-slice)

Variable: Layer thickness

Step 1)

In the alter menu, press 3 (3) to select the layer thickness.

Step 2)

Press V to select variable thickness.

Step 3) Add or delete the Z level if necessary.

Note: The first Z level must start at or below the bottom of the part.

Step 4)

Press S to save the layer thickness table.

Step 5) Press Q to return to the alter menu.

Step 6) Change other standard options as needed.

Step 7) Press E and set the other parameters to -y.

Step 8) Press S to save the options file as spike_p.UII.

Step 9) Slice From the main menu, press D to slice the spike_P file.

Step 10) Repeat the setting of parameters and slice the spike_b file.

[3.6 Control computer]

[survey]

All stereo lithography processes from MERGE to BUILD run on the control computer. This includes all the functions from elevator and mobile mirror control to creating parts from the transfer and merging of slice files.

For ease of operation, program and operating parameters are selected in the menu. An internal program configured in a top-down manner starts from the main menu and consists of a sub-menu, a data input screen, and a current status display screen. To select the desired option, press the corresponding numeric key of the option or use the arrow keys to place the pointer at the desired position and press the Enter key.

The menu structure of SLA-1 is illustrated in FIG. 24 and the following figures. Note that each menu includes an exit or quit option to return to the next higher menu. The exit option from the main menu means to leave the SLA-1 operating system and enter the MSDOS state.

[Commonly Used MSDOS Commands]

The control computer operates in a single-user, single-task MSDOS operating system.

The MSDOS prompt is based on the default disk drive. The file name is limited to 8 characters maximum, and the extension name can be up to 3 characters (eg .SLI).

MSDOS is a powerful operating system that allows multiple commands to be selected. However, most of the functions required in all operations of the SLA-1 can be performed using the decimal instructions summarized below.

Cd: Change Directory

.

Copy: Copies the file.

In the following example, one file is copied under another name in the same directory on the same disk. Then both files contain the same data, but have different names.

You can also copy the files to a floppy disk. For example, in the current directory TEST1. Copy EXT to disk drive A.

.

Delete: Deletes the file.

In the following example, TEST1. Delete the EXT file.

To delete multiple files with a common filename or filename extension, enter a command using an asterisk (*) instead of a common name.

E.g,

Will delete all files with the name TEST1 in the current directory whatever the extension is,

, All files with ext ext are deleted.

However, extreme caution is required when using *.

Directory: Lists the files and subdirectories in the directory. If you want to see a list of all the files in the current directory

do .

The following example lists only the files named File1 in the current directory (regardless of their extension) in the current directory.

In the following cases, all files with the .EXT extension will be displayed regardless of the file name.

Help: Shows available MSDOS commands, complete grammars, or abbreviations for specific commands. Some systems may not be able to use this command.

To list all commands

When

If you want to display the abbreviated form of a complete grammar or command on the screen

.

Rename: Rename the file.

For example, in the following case, rename the file TEST1 to TEST.

After changing the file name, the file named TEST1 no longer exists in this directory, but the same file exists under the name TEST.

[3.7 Utilities]

[survey]

Utility menu options are used during the part creation process.

● Power on and off the SLA-1 hardware.

● Measure the focusing intensity and focus of the laser beam.

● Move the elevator platform before and after building the part.

● Enter data for the curing depth and line width measured at the banjo top.

● Edit the text file.

● Make test parts.

[Utility Menu]

Power Sequencer

The laser, movable mirrors and elevator mover can be turned on or off directly from the keyboard of the control computer and the laser shutter can be opened or closed. In addition, the current state of each constituent part is displayed at the bottom of the screen.

[Beam analysis]

Measure the focusing intensity and focus of the laser beam so that the field engineer can adjust the laser.

[Beam Power]

After having the two beam probe fillers installed in the process chamber point to the laser beam, calculate the average beam power. The current value of laser power is needed when MATERIAL MENAGER, an option in the PREPARE MENU, is trying to calculate the hardening depth.

[Elevator Mover]

In the elevator mover program, the elevator platform position can be set using the up and down arrow keys on the numeric keypad of the control computer. Pressing the space bar stops the elevator movement.

With D, the elevator platform can be moved a certain distance in inches. If a positive value is given, the platform will descend and if it is negative, it will rise.

T toggles parameter information displayed at the bottom of the screen.

Operation Sequence (Lab 2 - Utility)

Power Sequencer

Step 1)

Step 2) From the utility menu, press 1 to select the power sequencer.

Press the corresponding numeric key on the Power Sequencer menu. The status display of each component displayed at the bottom of the screen is automatically adjusted.

Beam analysis

Step 1)

From the Utilities menu, press 2 to select Beam Analysis.

Step 2)

In the beam analysis menu, press 1 to select profile display or 4 to select beam power.

Step 3)

Display profile

After reviewing the pro-woofer Press to return to the beam analysis menu.

Beam power

After reading the output, enter the average value and return to the beam analysis menu.

Elevator mover

Step 1)

From the Utilities menu, press 3 to select Elevator Mover.

Step 2)

Press the arrow keys on the numeric keypad to raise or lower the elevator platform, press the spacebar to stop the elevator, press D to move the elevator by a specific distance (inches) Enter a positive number when you want to raise it, or a negative number when you raise it.

Intermediate material

General Information

[Edit file]

Used for editing text files.

[Create test part]

Test part creation is used to create a banjo saw.

[Material Manager]

Material Data Load: Lists material (.MAT) files and prompts for the next file to be loaded.

Material Data View: Displays material data on the screen.

New material data input: Input the measured material data from the banjo top.

Type of data

● Step cycle (SP) value

● Line height of each banjo top string

• Minimum and maximum line widths from each banjo top string

The new material data input then calculates the work curve and displays the curve's slope and Y-intercept on the screen.

Note: If you need to know more about the banjo top and work curve and their contents, see Measure 5.3.

Work Order (Lab 3 - Utilities)

Material manager

Step 1)

From the Utilities menu, press 4 to select Material Manager.

Step 2)

Press the number key of the corresponding option in the material manager menu.

Step 3)

[Material data load]

Enter the name of the material (.MAT) file.

The name of the data file to read:

After reviewing the material data Button.

[Enter new material data]

Note: If you run the 6. Generate Test Part option from the utility menu to create a banjo top, you will measure the benzodi top string and generate data for the material file.

Enter the file name of the material data with the extension .MAT appended.

File name of material data: test.mat do.

Enter the average laser power reading read at BEAM POWER (beam power).

Enter the power reading of the material testing laser (mW):

Enter the number of data pairs measured in the banjo top.

How many step cycle / line height pairs? 3

Enter the step cycle (SP), line height (LH), minimum and maximum line widths (WMIN, WMAX) as measured from the banjo top.

If WMIN, WMAX value is not measured, it is set to 0.

After reviewing the data accuracy Button.

[3.8 Network]

[survey]

A network (program) is a program that transfers files between a control computer and a slice computer via Ethernet and enables remote control of the slice computer by manipulating the keyboard of the control computer (see Attachment 25).

Network menu

[File Transfer Program]

The file in the slice computer directory is copied and moved to the working directory of the control computer or vice versa. In general, FTP is used to transfer .SLI files to the control computer. Several commands are available.

Prompt: FTP

[File Transfer Command]

get: Sends the file from the slice computer to the working directory of the control computer. The file is copied, so it remains in the directory of the slice computer even after the transfer is complete.

It is similar to mget: get, but has the difference that you can transfer multiple files at the same time.

put: Sends a copy of the file from the working directory of the controlling computer to the slice computer. Since the file is copied, it remains in the directory of the control computer even after the transfer is completed.

mput: Similar to put, but has the difference that you can transfer multiple files at the same time.

dir: Shows a list of all files in the slice computer directory. Press CNTRL-S to stop displaying the list, or press CNTRL-Q to restart.

ldir: Shows a list of all files in the working directory of the control computer.

bye: Exit FTP and return to main menu.

help: Shows and explains all available commands.

Work Order (Lab 2 - Network)

Step 1)

From the main menu, select Network.

1 or put a pointer

Step 2)

From the network menu, press 2 to select FTP.

Step 3) At the prompt, enter the remote user name.

Remote user name: train

Step 4) At the prompt, enter your password. It is not displayed on the screen.

Remote password:

Step 5) At the ftp prompt, enter the appropriate command.

Note: You must specify the format (ASCII or binary) of the file to be transferred.

• Slice files are in ASCII format, and .STL files are in ASCII or binary format. The default is ASCII format.

• Files transferred from UNlX (slice computer) to MSDOS (control computer) must conform to the DOS filename convention. That is, the file name is limited to eight characters, and the extension is limited to three characters.

[Intermediate material]

[Terminal Utility]

As shown in FIG. 26, the terminal utility allows a user to log on to a slice computer from a control computer keyboard to operate slice programs and other programs remotely. These options are rarely performed, because these are rarely performed because the control computer is typically used to create the part.

Work Order (Lab 3 - Network)

Step 1)

Step 2) From the main menu, select Network.

1 or put a pointer

Step 2)

From the network menu, press 1 to select Telnet.

Step 3) At the prompt, enter the remote user name.

Sign in: train

Step 4) At the prompt, enter your password. It is not displayed on the screen.

password :

Step 5) At the UNIX prompt, enter the required command.

UNIX System V Release 1.0.4 80386

$

Step 6) When done, terminate TELNET.

[3.9 Merge]

[survey]

As shown in FIG. 27, the merge combines all slice files (support and object files) for the part to produce layer (.L), vector (.V), and range (.R) files.

Layer (file.L) file: Defines the vector block type for each layer.

Vector (file.V) file: Contains vector data used by BUILD to draw each layer.

Scope (file.R) file: Specifies the construc- tion parameters and settling parameters for the BUILD. You can change this file using the prefix option to add part creation parameters.

Merge information screen

The merge information screen is used to input file information. This screen displays the following status information when the merge is running.

The start and end values of the Z level for each layer thickness range

● The current Z level is being merged.

When execution is complete, the total number of processed ranges and the number of layers merged in each range

Work Order (Lap 2 - Merge)

Before you start

Execute the option FTP in the network menu to transfer all necessary slice files to the working directory of the control computer.

Step 1)

Step 2) From the main menu, select Merge.

2 or put a pointer

Step 2) Enter the file name to be merged.

Slice file name:

Step 3) Enter the layer, vector, and range file, or press the Enter key to select the default filename.

Output file name: Prefix

Step 4) At the prompt, select the default layer thickness Button.

Layer thickness (mils [10])?

Step 5)

Look at the screen to determine when the merge is complete.

Note: Slice files prior to version 3.0 may require Z-space input.

[Medium]

[Merging Options]

/ Z Adjust the vertical position of the files relative to each other. This option is used to align objects vertically. Enter the offset in slice units after the file to be adjusted.

Slice File name: cam_part ^ cam_base / z100

/ X Adjusts the X position of the file relative to each other.

/ Y Adjusts the Y position of the file relative to each other.

[3.10 View]

[survey]

The view displays the stereo lithography (.STL) and slice (.SLI) files on the control computer as shown in FIG. It is mainly used for the following purposes.

• Evaluate whether it is necessary to change the layer thickness.

Determine if all vector blocks are required.

● Study layer and component properties.

● Check the slice file.

View menu

Triangle graph

New Files: Specify a new file name to be displayed as a graph. When the triangle graph option is selected, the .STL in the working directory is listed.

Graph: Shows the file as a graph.

Rotation: Specifies the angle of rotation in the X, Y, and Z axes according to the right hand rule (RHR) specification. For example, to show a view of the same size as the part, the X axis is rotated by 30 degrees, the Y axis by 15 degrees, and the Z axis by 0 degrees.

ESC: Exit the triangle graph function and return to the view menu.

Window mode: Advanced material.

Select Range: Advanced Material.

[Sliced Layer Graph]

New file: Specifies the file name to be displayed as a graph. When the Sliced Layer Graph option is selected, a list of .SLI files in the working directory appears.

Layer selection: represents a list of vector blocks of each layer in the file. This parameter is used to select the slice layer with the important vector. When a layer is selected, the X and Y min / max values for the selected layer are displayed in slice units, and the mnemonic symbols for all blocks in the layer are displayed.

Block: Specifies the vector block to be displayed when the part is shown. With the toggle function, the selected block in the next graph of the file can be omitted.

Graph: Shows the file as a graph.

ESC: Exit the slice file display function and return to the view menu.

Windowing: Advanced material

[Screen mode switching]

Allocate free disk space between the stereo lithography and the slice file. In most cases, the default does not need to be changed. However, if a very large .STL file is shown, more triangles (up to 10,921) are allocated. If a very large .SLI file is shown, more layers are allocated (up to a maximum of 10,921). If both files are shown, allocate disk space appropriately.

Work Order (Lab-View)

Before you start

To display the .STL file:

● Generate files in ASCII or binary format.

Transfer the file to the control computer working directory using a floppy disk or data transfer option.

To display the .SLI file:

● Execute slice (SLICE) if no file is created.

Transfer the file to the control computer working directory using a floppy disk or data transfer option.

Switch the screen mode

Step 1)

From the main menu, select View.

3 or put a pointer

Step 2)

The disk space shown at the bottom of the screen is reviewed to determine if memory should be reallocated to the file. In most cases, you do not need to change the default value.

Step 3) If you need to change the assignment, press 3 to select Screen Mode Switching, then enter the appropriate number of slice layers at the prompt.

Viewing a stereo lithography file

Step 1) From the main menu, select View.

3 or put a pointer

Step 2) From the View menu, press 1 to select the triangle graph.

Step 3) At the prompt, enter the name of the stereo lithography file.

Enter file name: cam_part

Step 4) At the prompt, enter the file type (ASCII or binary).

Step 5)

Step 6) To rotate the display axis, press R, then enter the rotation angle for the X, Y, Z axes.

XYZ axis rotation: 15 ^ 10 ^ 0

The screen is automatically updated to show the selected rotation of each axis.

Step 7) Press W to toggle between display modes.

Step 8) To change the display axis, press A and then enter the display axis at the prompt.

New axis: X

It will be updated by automatically re-scanning the screen to show the selected display axis.

Step 9) To specify a new file to be displayed, press N and then enter the file name at the prompt.

Enter new file name: cam_part

Step 10) To display the file, press G. (See also Figure 29)

[View sliced files]

Step 1) Select the view from the main menu.

3 or put a pointer

Step 2) From the View menu, press 1 to select the sliced file graph.

Step 3) At the prompt, enter the slice file name.

Enter file name: cam_part

Step 4)

Step 5) To select a specific file to be shown, press L and enter the layer number at the prompt. Press PgDn to move to the front of the list and PgUp to move backward.

Enter the floor number: 5000

The screen is automatically updated to display the maximum / minimum dimensions of the vector block associative symbol layer in slice units.

Step 6) To select a vector block of the layer to be toggled on or off, press B and enter the block type at the prompt.

Block type to toggle: fuh

The selected vector block will toggle on or off until a new layer is selected or a new file is loaded.

Step 7) Press W to toggle the display mode.

Step 8) Press G to show the slice file as a graph (see Figure 30).

[3.11 PREPARE]

[survey]

The pre-pair menu options are used to specify component construction parameters such as laser plotting speed and elevator settling time and to edit the range (.R) file.

[Parts construction guidelines]

[Layer Overlay]

By curing each layer to 0.006 inches, the interlaminar adhesion can be improved (ie, the 0.020 inch thickness layer has a cure depth of 0.026 inches).

[Settling Delay]

The time required for the resin surface to stabilize and stabilize after the part has settled. It depends on the shape of the part and various other factors.

[Common parts construction parameters]

[SS] (step size) SLA-1 draws the vector only in consecutive movements. The dynamic mirror actually moves the beam to the discrete step and then pauses for a while. The step size is the size of the movement in mirror bits. In general, the step size for the boundary and crosshatch is set to 2 (minimum tolerance). The step size for the skin fill vector is typically set to 16.

[SP] (step period) is the length of the delay following each laser step. The larger the SP, the slower the laser construction speed and therefore the greater the depth of the cured plastic.

[ZW] Specifies the leveling time at which the resin surface becomes stable and flat after sedimentation. Generally, ZW is 30 to 60 seconds for support. Usually 45 to 180 seconds are set for component construction.

[range]

The range is a group of one or more slice layers defined by the minimum and maximum dimensions defined in CAD units or slice units. A range is created whenever a component creation parameter value for a group of layers needs to be specified.

For example, a 30 second settling delay is required for the support layer, and 60 seconds for all remaining layers, two ranges must be defined. The first range includes a layer of 30 ZWs, and the second range includes all layers with delays 60. [

Another example where ranges are often used is to modify the layer hardening depth. A range containing a small number of first support layers will be generated with a hardening depth wider than the specified range for the remaining layers.

Use the pre-pare menu option to create the required range.

Prefere main menu

Parameter manager menu

Use the Parameter Manager to add or change part creation parameters.

Z-pitch

This parameter controls the sizing of the part in vertical dimension.

[XY-limited scale factor]

The XY-limited scale factor converts the distance of the slice unit into the laser beam movement value on the resin surface.

A feature of a mobile mirror is that it moves the laser beam one inch above the resin surface for every 3446 mirror bits (or 140 bits per mm) transmitted to the mirror driver. Because 3556 is an inappropriate number to use in slice resolution, the conversion factor is used.

For example, if a CAD file designed in inches is sliced at a resolution of 1000, all inches of the object are represented in 1000 slices instead of 3556. Therefore, all vectors in the .V file are too short by the factor 1000/3556 = .3556, so if you use them as they are, the final part becomes too small. The build multiplies all vector coordinates in the .V file by an XY-specific scale factor. Therefore, by setting this parameter to 3556/1000 = 3.556, the vector is adjusted to an appropriate length. In general, the formula is expressed as an XY-specific scale = 3556 mirror bits / slice per inch.

The component size can be readjusted using the XY-specific scale factor. For example, to increase the horizontal dimension of the aforementioned components by 10 percent, use the scale factor of 3.556 * 1.10 = 3.912.

To reduce the horizontal dimension by 50 percent,

3.556 * 0.50 = 1.778.

[Maximum vector count]

This parameter specifies the maximum number of vectors that can be loaded into the mobile mirror buffer before the mobile mirror starts moving to create the part.

[Min / Max viewport coordinates]

The build viewport coordinates specify the minimum and maximum coordinates (in mirror bits) of the window display of the tank shown in the build status display screen. The limits of the coordinates are (0, 0) and (65535, 65535).

For example, if you want to view the cam while the cam is being created, use the viewport coordinates.

CAUTION: The cam is approximately one inch in diameter.

(Xmin, Ymim) = center of tank - 1/2 part width

= 32767 - 0.5 * 3556

= 30989

(Xmax, Ymax) = center of water tank + 1/2 component width

= 32767 + 0.5 * 3556

= 34545

Since the coordinates calculated for the X-Y offset are for the part center, the mirror bit must be subtracted from the offset to display the entire part. At a minimum, a number similar to 1/2 of the component width should be added to the maximum offset.

To show the entire 9-inch * 9-inch work surface, enter the following:

(Xmin, Ymim) = 32767 - 4.5 * 3556

= 16765

(Xmax, Ymax) = 32767 + 4.5 * 3556

= 48769

Multiple Part Positioning

These parameters are used to set the position of the part on the elevator platform and to create multiple parts in the same build run.

In order to calculate the coordinates needed to position the part in the center of the resin bath,

● Component center coordinates of CAD space

● The coordinates of the center of the tank, about (32767, 32767). If necessary, accurate coordinates can be obtained.

For example, if the X-Y center of a part is 2.3 inches, 4.1 inches, and the water tank center is 32767, 32767,

X-offset = Resin center - (CAD center * 3556)

= 32767 - (2.3 * 3556)

= 24588

Y-offset = Resin center - (CAD center * 3556)

= 32767 - (4.1 * 3556)

= 18187

In addition, the plural-part positioning coordinates can be used in a case where a plurality of copies of the parts are to be made in the same execution. For example, if you want to make four copies of the parts used in the above example, you would have four of the coordinates representing the center (X1 / Y1, X2 / Y2, X3 / Y3, X4 / Y4) The set must be computed.

If all four copies of the part are gathered at the center of the resin tank and are separated by about 2 inches in both X and Y directions, the tank center coordinates are first calculated in the same manner as in the above example, The same mirror bit as the half value of the predetermined distance is added and subtracted.

Separation interval = 2 inches / 2: 3556 bits

X1 = Xc + 3556 = 24588 + 3556 = 28144

Y1 = Yc + 3556 = 18187 + 3556 = 21743

X2 = Xc - 3556 = 21032

Y2 = Yc - 3556 = 14631

X3 = Xc + 3556 = 28144

Y3 = Yc - 3556 = 14631

X4 = Xc - 3556 = 21032

Y4 = Yc + 3556 = 21743

[Build Option Line]

These parameters define the orientation of the build viewport.

[Update build parameters on disk]

This command saves all other parameter managers in the disk entry of the build.prm file.

Range manager menu

The scope manager is used for:

● Adding or deleting ranges

● Step cycle calculation (laser operation speed)

● When you edit the range to change the settling delay

● When saving a range (.R) file

Range Manager menu list:

● Range (.R) File name

● Range number assigned when range is added

● Starting and ending range dimensions, expressed in CAD units and slices. In the screen shown, the slice resolution is 5000, so the CAD dimensions 0.73 inches (bottom of the part) and 1.37 inches (top of the part) correspond to slice units 3650 and 6850.

● Floor thickness in CAD units and slice units.

● The total number of layers in each range.

● Commands used to change or save .R files

Scope manager command

[A] Adds a range to a temporary range file. The .R file is not changed until the SAVE command is used. The start range layer can be entered in slice units or CAD units. The break point is the first layer of the range.

[D] Deletes a range from the screen. (For example, data deleted from range 2 would be merged into range 3, and range 3 would be merged into range 1) if more than one range remains.

[E] Enumerates (for editing) each vector block within the specified range. This command is mainly used to add a settling parameter to the range.

[V] Prove through a .L file that only the vector blocks contained in each range are listed for editing in a temporary .R file. These blocks are blocks that are edited to control the step cycle, step size, and other component usability parameters. The vector block and range are not recorded in the .R file on the disk until the file is stored using the S command.

[R] Displays vector blocks within each range on the screen or hard copy via an optional printer port.

[X] Exits the Scope Manager and returns to the prefere menu. .R files are not saved using this command.

[S] Permanently stores the .R file containing all the information entered using the scope manager on the disk.

[C] Calculate the step cycle and input the hardening depth / step cycle information into the temporary range file. The CALC SP command is:

[R] Read the line height and width data from the material data (.MAT) file. The .MAT files in the working directory are listed on the screen for convenience.

[P] Changes the laser power reading displayed on the screen to the latest reading measured by utility beam analysis.

[E] Edit the coin depth and estimated step cycle shown on the screen.

[V] Material data is displayed from a material data (.MAT) file.

[Q] Exit the CALC SP function and return to the main menu. Changes entered using the pre-pare menu option are not saved.

[S] Add SP and SS laser angle parameters to the appropriate vector blocks in the temporary scope file. Parameters can be added to all vector blocks in the file, only to the boundary and hatch blocks, or only to the peb blocks. (A merge set may consist of only one file in a slice file that is mergeed into a vector block). The merge set consists of each vector block (i.e., LB2) Note that this update command updates only the temporary range file, not the .R file. To save the .R file to disk, use the Save command of the scope manager menu .

[X] Exit the CALC SP and return to the Range Manager menu.

Work Order (Wrap 2 - Pre-Paired)

Parameter Manager

Step 1) In the main menu, press 4 to select the pre-pair function.

Step 2) At the prompt, enter the prefix of the part file.

Part Prefix: glass

In the pre-pare main menu, press 1 to select the parameter manager.

Step 4) Set the XY-limited scale factor to .7112 (3556/5000).

Step 5) Set the X offset to 17000 (32767 - (4.5 * 3556)).

Step 6) Set the X offset to 17000.

Step 7) (Optional) To make the two parts,

(X1, Y1) to (15000, 15000) and

(X2, Y2) is set to (15000, 25000).

Step 8) Change the viewport coordinates

Xmin, Ymin = 5000, 5000

Xmax, Ymax = 35000, 35000

.

Step 9) Press U to update the file on the disc.

[Scope manager]

[before start]

Run the utility beam analysis (BEAM ANALYSIS) to measure the current laser output. Record the average of the readings of sensors 1 and 2.

Step 1)

From the pre-pare main menu, press 2 to select Range Manager.

Add range

Step 1)

From the Range Manager menu, press A to add a range.

Step 2) Press Z to add the range dimension in slice units, or press C to enter the dimension in CAD units.

Adding Range

Press Z to enter the Z layer. Number: Z

Step 3) Enter the beginning of the range in slice units.

Enter break point, in Z-Layer units: 3750

Step 4)

Examine the screen to prove that the range is added properly.

Step 5) Add another range starting at 4950.

Step 6) Add a fourth range starting at 6000.

Delete scope

Step 1)

From the Range Manager menu, press D to delete the range.

Step 2)

Enter the range number you want to delete.

Delete range: 3

Examine the screen to ensure that the scope has been deleted.

Step 1)

From the Range Manager menu, press V to verify the block.

Step 2) Enter y in the caution message.

Verifying will ‥‥ commands. continue?

y

report

Step 1)

From the Range Manager menu, press R for the report.

Step 2)

Press V to view the report on the screen, or press P to print the report on the printer. If the printer option is selected, the report will not be shown on the screen.

Step 3)

To continue, Button.

Step cycle is calculated.

Step 1)

From the Range Manager menu, press C to compute the step cycle.

Step 2)

From the CALC SP menu, press P to change the laser power reading

Step 3) Input average power from beam analysis.

New Laser Power Readout (mW):

Step 4) From the CALC SP menu, press E to edit the cure depth / step cycle data.

Step 5) Enter the roughening depth required to bond the roast first extent to the platform (including the first two layers of support), then enter the range number and the new hardening depth.

cl, 35

Note: The selected curing depth must be at least 6 mils greater than the layer thickness for proper bonding between layers. The hardening depth for the first two layers of support should be deep for strong bonding to the platform. In this case, the required curing depth is 35 mils.

Step 6) Enter the hardening depth of 16 and the hatches in the range 2 to 3 for all layer boundaries.

c2, 16

c3, 16

Step 7)

From the CALC SP menu, verify the change.

Step 8) From the CALC SP menu, press S to save the range.

Step 9)

To specify which vector group to update or to select the default group shown in parentheses Button.

Which block group to use [1]?

Step 10) Specify the merge set you want to update or select the default in parentheses Button.

Merging set to update [all]?

Step 11) Press E to begin editing the skin hardening depth by entering the hardening height of 26 mils (which will be 6 mils larger than the selected 20 mil layer thickness) after pressing E.

c2,26

Step 12) Divide the final step period 90 in half, press E, then enter the skin fill SP value in the range 2 to 3.

S2, 45

S3,45

Step 13) Press S to save the file.

Step 14) At the prompt, specify the update of the skin fill block (block group 2).

Which block group to use [1]? 2

Step 15) At the prompt, to update all merge sets Button.

Updated merge set [all]?

Step 16) From the CALC SP menu, press X to exit the CALC SP function.

Step 17) From the Range Manager menu, press E to edit the range to add the settling delay.

Step 18) At the prompt, press 1 to edit range 1.

Scope to edit? One

Step 19) At the prompt, add a 30 second settling delay to the #BTM record.

Enter the command for #BTM: ZW ^ 30

Step 20) Edit range 2 to add a 30 second settling delay.

Step 21) Edit range 3 to add a 120 second settling delay.

Step 22)

From the Range Manager menu, press S to save the .R file to disk.

[Middle topic]

[Floor manager menu]

LAYER MANAGER is mainly used to find specific vector blocks in a .L file. Other functions such as edit (EDIT) and update (UPDATE) are higher functions.

The Floor Manager screen lists:

-.L filename

- the number of ranges specified in the .R file

- start and end range dimensions in slice units

- layer thickness in slice units

- total number of floors in the range

- Operation command

[Floor Manager Command]

[F] Find a specific vector block in a .L file and list the number of layers. For example, if you want to determine where merge-set 3 starts in Z space, press F to find the block, and enter L3 and ALL in the prompted state. The layer manager lists all the slice layers on the screen including the vector block L3. This is quick and convenient compared to finding a particular vector block by exiting the prefere menu and executing the view.

Statistics

STATISTICS lists layer, range vector file information and includes:

- File size in bytes

- The time and date the file was created

- Remaining disk space

Work Order (Lap 3-Prefere)

Statistics

Step 1)

In the pre-pare main menu, press 4 to select a statistic.

To continue Button.

[3.12 BUILD]

[survey]

BUILD manages the parts-building process by reading the vector (.V) file and the scope (.R) file and sending the appropriate commands and parameters to the dynamic mirror and elevator driver. This includes the following:

- deflect the laser beam to track the vector on the surface of the resin bath.

- Control the laser passing speed to ensure proper curing depth.

- Controls the interlayer settling sequence (settling, raise, level).

BUILD Options Screen

This screen is used to input the part file name and display the part construction information.

Optional: See intermediate topic or pre-pare menu options PARAMETER MANAGER

XY-scale: Lists XY-specific scale vectors.

Number of Parts: Shows the number of redundant parts to be created.

X, Y: List multiple part positioning coordinates.

Part directory listing: A list of files in the working directory.

Part file name: Part specific to be built

[BUILD Status Screen] See Figure 31 for BUILD Status Screen.

This screen displays current status information while the part is being built.

Part: Name of the part to be built

Control: Range control specific (default)

Action: Current BUILD action list box.

LOADING: When the laser beam positioning data is loaded into the buffer.

LEVELING: If BUILD is waiting for the water tank to stabilize and flatten during sedimentation or sedimentation.

Drawing (DRAWING): A vector is drawn on the surface of a resin tank.

AMALYSING: When BUILD is analyzing or calibrating laser mirror drifting.

Time (TIME): Lists the number of seconds remaining in the settling delay.

START / END TIMES: List BUILD start and end times and dates.

START / ON / END LAYER: Start and end of a part. Floor number, list of currently drawn layers.

Block (BLOCK): A list of symbols (mnemonic) of the currently processed vector block.

Viewport (VIEWPORT): Resin tank cross section and part cross-sectional view. While the vector is drawn on the surface of the resin, it is also drawn on the screen.

[Work Order (Wrap 2-BUILD)]

Before the start

- Moving the elevator platform below the surface of the resin using an elevator shifter.

- Open the spillway valve on the front of the water tank and replace the water tank with the platform support bar to overflow the overflow container.

- Raise the elevator until the upper side of the platform is slightly above the resin side.

- Close the door to the process chamber.

- Check that the laser on and shutter open indicator are on. Use a power sequencer on demand to turn on the laser or close the shutter.

Step 1)

Select BUILD from the main menu.

5 Or hold the pointer position

Step 2)

Enter the part file name from the listed file.

Part file name: cam

Step 3) (See also 32 in the BUILD status screen)

Check the status screen and parts periodically to make sure of the following:

- The first few layers are attached to the elevator platform.

- Does the part come to the center in the resin tank?

- Are the layers with different layer thicknesses adhered to each other?

If there are problems with parts manufacturing To stop the BUILD. This will return you to the main menu.

[INTERMEDIATE TOPICS]

[Keyboard Commands]

During the leveling action, BUILD accepts three keyboard commands.

[P] Stops BUILD until another key is pressed. The leveling time continues to zero. A stop message is displayed on the command line at the bottom of the screen.

[C] The component building process is continued by ignoring the remaining leveling time and immediately starting the next layer.

[S] Jump to a specific Z level. The first layer at or above the Z level is drawn. This command can only operate at low to high Z levels

Command line options

/ LOFF: Turns off the dynamic mirror driver. This option is used with / ZOFF to perform BUILD without making parts.

/ ZOFF: Turn off the elevator driver. This option is used with / LOFF to perform BUILD without creating a part.

/ START: Specifies the start Z level when building the part. All lower layers are skipped. Use / START to start building from the middle of the part. For example, when you start to create a sample part at Z level 5000, type:

Component file name:

/ STOP: Specify 2 levels to terminate when building parts. All upper layers are skipped. Use this option with / START to construct a section of the part. For example, to build a layer with a Z level of 5000 to 5500, type:

After the final layer is drawn, the elevator does not settle.

The / LOFF and / ZOFF commands are often used with / START and / STOP to check whether a part enters the viewport.

For example, type:

The mirror will not draw the floor, and the elevator will not move. If the part is properly displayed in the viewport, build the part by restarting BUILD without command line options. Otherwise, use PARAMATER MANAGER to edit the viewport coordinates.

[3.13 Follow-Up Process]

[survey]

The subsequent process is to cure and finishing green stereo graphics components. The green part consists of semi-interchangeable plastic and liquid, and its exact configuration depends on several factors, including the type of resin used and the type of crosshatch selected.

The main follow-up steps are as follows.

- draining excess resin to resin tank

- wicking to remove resin from corners and other parts details

- UV hardening to solidify the uncured parts of the part

- Remove support

- Optional finishing: sanding, sandblasting, painting,

[General information]

[Drainage]

The liquid resin is drained from the parts to the resin tank. Drainage times generally range from 30 minutes to 24 hours. Note, however, that exposure to prolonged exposure to the atmosphere may weaken the structure of the part and interfere with UV curing. A thermal oven accelerates this process, but it can also have the adverse effect of making the dimensions of the part inaccurate.

Care should be taken when tilting or otherwise changing the green parts. It can be easily peeled or deformed by laser before UV curing.

[Wicking]

Remove any excess liquid around the corners and details of the part.

[UV curing]

The polymerization process is completed to produce solid plastic parts. Check the hardness of the surface to ensure that the cure is complete.

The usual sequence of work is to harden the exposed surfaces while attaching the parts to the platform, to cure all remaining surfaces after removing the platform.

[In Air]

The most common curing method. Exposed for 12 hours in air to be structurally sound. The disadvantage of air hardening is that the parts can become yellow and deformed by excessive heating.

[In Water]

By immersing the component in water, the curing time can be greatly shortened because the water does not absorb ultraviolet light but acts as a heat sink to cool the component and minimize deformation. Air bubbles can cause blistering, thus eliminating all air bubbles. Short, rapid curing (5 minutes) is effective.

[Support removal]

Remove the support from the part by clipping or sanding.

[Work Order (Rep 2 - Follow-Up Process)]

[Drainage]

Step 1)

From the main menu, select UTILITIES.

6 Hold pointer position

Step 2)

From the utility menu, press 3 to select the elevator mover.

Step 3) Use the up arrow key on the numeric keyboard to slowly raise the elevator by three inches (slow down to prevent component deformation)

Step 4) Wait for 30 minutes until the excess resin is drained into the resin tank.

[Removal of parts and platform from chamber]

Step 1) Place the drain pad on the drain tray.

Caution: When removing the platform from the elevator rod, do not collide the elevator with the drain tray. May damage the elevator.

Step 3) Press the down arrow key to lower the elevator platform to 1/4 inch above the drain pad.

Step 4) Alternately turn the elevator shaft knobs counterclockwise once. This will cause one end of the shaft to be released from the platform. Repeat this process until the platform is separated from the shaft and drops to the drain pad.

Step 5) Press the UP ARROW key to raise the elevator shaft as needed for drain tray and platform removal.

Step 6) Remove the process tray from the process chamber with parts attached to the drain tray and platform. Keep the platform level to prevent damage to the components.

[Wicking]

Step 1) Place the elevator platform with drain tray and part on the work surface.

Step 2) Use a swab to gently wipe excess resin from the corners and other areas that are not fully drained. Wait as long as necessary and repeat.

[Subsequent hardening]

CAUTION: Always wear gloves

Step 1) Place the elevator platform with the drain tray and the parts on the PCA.

CAUTION: Do not place drainage pads or other flammable materials on the PCA.

Step 2) Subsequent curing of the part until all surfaces exposed to the ultraviolet lamp do not become entrapped.

Step 3) Using a fine saw, cut the support near the platform attachment.

Step 4) Remove the sawdust and other pieces by rinsing the parts before continuing. Properly dispose of the residue.

Step 5) Invert the part (or turn it sideways) to expose the uncured surface to the ultraviolet lamp in the PCA.

Step 6) Continue curing until all surfaces are not cured. You may have to run it several times.

[Platform replacement]

Step 1) Scrape off the resin residue from the platform. Tap out threaded holes with # 10-32 tabs on the platform.

Step 2) Secure the platform under the elevator bar so that the threaded hole of the platform is in line with the threaded end of the rod.

Step 3) Turn the shaft knob clockwise one after the other. Repeat this step until the platform is firmly seated in the elevator shaft.

[Support Removal and Cleanup]

Step 1) Cut the support with files, grinding tools, side cutting pliers or a suitable tool.

Step 2) Smooth the surface with a line.

3) If necessary, sand, sandblast and paint the parts.

[PCA operation]

Step 1) As shown in Figure 33a, the parts are placed in the center of the oven with the parts attached to the platform. Adjust the lamp direction so that the exposure is even on the most surfaces (close to 90 degrees as much as possible).

Step 2) Set the timer to 10 to 20 minutes.

Step 3) Turn off the main power switch (MAIN POWER) after the lapse of time.

Step 4) Remove the part and platform from the oven and separate the part from the platform. Be careful not to deform the uncured surface.

Step 5) Change the orientation of the part on the turntable as shown in Figure 33b so that the remaining surface is mostly cured.

Step 6) Repeat steps 2 and 3.

Step 7) Reorient the parts and ramps to cure all remaining surfaces as shown in Figure 33c. You may have to run it several times.

[3.14 Part Building Checklist]

Scope (SCOPE)

This checklist serves as a step-by-step guide to building stereo lithographic components. The starting point is a CAD design that does not refer to stereo lithography at all. All necessary hardware or software systems are assumed to be installed and operational.

Checklist

1. CAD Design

- Ensure that the object surrounds the closure volume.

- Select the required CAD resolution.

2. Orientation of parts (ORIENT PART)

- Position the part as close to the origin as possible and in the positive Cad space.

- Optimize orientation for:

Allow parts to enter the resin bath.

Minimize the number of unsupported surfaces.

Maximize vertical or upward horizontal surface.

Minimize sloped or tilted surfaces.

Optimize multiples.

Thereby minimizing the amount of liquid entrapped therein.

3. Support Design and Orientation

- Support design

Placement

Spacing

Orientation

Height

area

thickness

- Overlay two or three layers of support with the object

4. CAD interface

- Generate a stereo lithography file.

- Transfer the .STL file to the slice computer.

5. Slice

- Change the standard option.

Name of the database file

resolution

Layer thickness

Hatch interval

Skin Peel Spacing

Minimum surface angle for scanned facets

Minimum hatch cross angle

Output file name

- Extra parameter assignment

- Save option file

- Perform a slice to split the file

- Continue to slice objects and support files

6. Transfer slice file to control computer

- Select Network from the main menu.

- Run FTP.

- File GET or MGET

- Checking the working directory of the control computer to verify the transfer

7. Merge

- Select MERGE from the main menu.

- Input and output file name.

- File name and recorded sequence.

- Check the MERGE screen to make sure the execution is complete.

8. Laser power measurement.

- Select Utility from the main menu screen.

- Execute beam analysis (MEAN AMALYSIS).

- Record average power from detector scales.

9. PARAMETER MANAGER

- X-Y limit (ONLY) Calculate and input the scale factor.

- Calculate and enter the minimum / maximum viewport coordinate values.

- Calculate and enter multiple part positioning coordinates.

10. Prepare the range file (PREPARE RANGE FILE).

- Add range.

- Check the block.

- Edit the hardening depth to calculate the step cycle.

- Edit the settling parameters.

- Save the scope file.

11. System check

- Open the lid of the resin tank.

- Open the overflow valve.

- Check the laser and shutter status indicators.

- Position the elevator platform using elevator mover.

12. Component construction

- Select BUILD on the main menu screen.

- Check that the first few layers are well attached to the platform and are in proper position in the tank.

13. Subsequent processing

- Extract the parts and drain the remaining resin into the water tank.

- Wipe the remaining resin.

- UV cure the parts on the platform.

- Finish the curing and remove the part from the platform.

- Remove supports from the part.

- (Optional) Clean the surface.

- Clean and reinstall the platform.

14. (Optional) Stereo lithography and slice file view.

-.STL file is transferred to FTP using FTP.

- Select VIEW from the main menu.

- Enter the file name and specify the viewing parameters.

[Section 4]

[Problem Solving Technique]

4.1 Limitations of Stereo Lithography

File size

Maximum stereo lithography (.STL) file size is limited to approximately 14,000 triangles.

The total size of all MERGE input files is one-half the available space on the control computer hard disk.

Use the DOS menu option DISK USAGE STATS to determine the available hard disk space.

BUILD work files - vector (.V), range (.V), layer (.L), BUILD. The maximum size of the PRM- is limited by the available space on the control computer hard disk.

Part build limitations

· Parts (object and support) formation is limited to 9 inches at all dimensions. However, it is possible to create some sections of a larger part by several runs and re-fit them in subsequent processing.

Parts must be attached to the platform (can not be built in free space). Potential free flating parts should also be supported to keep the part in place when it is settled.

· Maximum (recommended) Curing depth is 0.036 inches. This is because the work curve for making the relationship between the hardening depth and the step cycle does not extend beyond 36 mils. As a result, the maximum layer thickness is limited to 0.030 inches.

Vertical and up-facing horizontal skins are smoother than down skins. This limitation can be minimized by determining the direction of the part so that the surface of interest is vertically or upwardly oriented.

Vertical resolution is limited to a certain thickness. In areas where vertical resolution and dimensions are important, this limitation can be minimized by using a variable layer thickness to specify a thin surface. You can also determine the direction of the part so that the vertical dimension changes (for example, from Z to X or from Z to Y).

Theoretically, the maximum slice resolution is 65.535 bits.

The positioning accuracy of the laser beam is limited to 2 mils anywhere in the working field.

The maximum number of files that can be merged and created in one run is ten.

• By default, the SP parameter is less than 10. However, default values can be modified using the Prepare menu option.

The resolution of the final part depends on the resolution of the CAD model used to generate the STL file.

• Desolite SLR 800 resin is fragile after subsequent curing.

4.2 Problems during construction and healing methods

Problems in the construction of parts and their countermeasures for healing are shown below. Hardware and software problems are not shown.

[Section 5.0]

Resources

5.1 Laser theory

5.2 Chemical theory of stereolithography

5.3 Bleed, benzotop and work curve

5.1 Laser theory

SLA-1 laser

SLA-1 uses helium-cadmium and multimode ultraviolet lasers to create solid plastic parts by drawing vectors onto photo-curable resins. The power of the laser beam varies and is typically 15 milliwatts at a wavelength of 325 nanometers.

Ultraviolet light is an invisible light, but fluorescent light is emitted from matter when ultraviolet light is irradiated to almost all materials, including resin, with intensity from the SLA-1 laser. Therefore, it can be seen on which surface the laser beam is projected. It is especially useful when aligning the optics and also allows you to see the laser drawing on the resin surface.

As shown in the figure, the laser consists of a U-shaped glass plasma discharge tube with electrodes on both ends and an optical window at one end of the straight section. The plasma tube is filled with low pressure helium gas and has a solid cadmium storage.

The cadmium reservoir is heated to vaporize the cadmium and mix it with the helium gas. The high voltage potential supplied to the electrodes of the plasma tube ionizes the mixture of gases to create an electric field. The free electrons activated by the electric field collide with cadmium atoms and transfer energy. This energy causes the cadmium atom to become an unstable excited energy state. This excited atom spontaneously abandons their excess energy and returns to a unexcited steady state. This excess energy is emitted in the form of photons (discrete units of light energy) at the exact wavelength characteristics of cadmium.

The above-mentioned device is not a laser but a weak plasma discharge lamp. To create the laser, place mirrors perfectly aligned in parallel at one end of the plasma tube. The mirrors are optical resonators and are designed to reflect photons with one of the cadmium intrinsic wavelengths (325 nanomipers) passing through other wavelengths.

A small amount of photons transmitted in parallel on the resonator axis is reflected by the resonant reflector and returned to the plasma tube. When one of the reflected photons collides with an already excited cadmium atom, it stimulates the atoms to emit excess energy in the form of a photon with the same direction, phase and wavelength of movement as the reflected photon.

Since the first photon is not consumed by this interaction, two identical photons are reflected back and forth between the reflectors in the tube tube and produce more of the same kind of photons.

A resonant reflector located at the laser output portion reflects a large portion of this coherent photon and passes a small portion. This transmitted photon is used by SLA-1 to cure the stereolithography resin.

Laser mode

SLA-1 lasers emit laser beams at different TEMs (Transverse Electromagretic Modes) simultaneously. TEMS is the product of the electric field in the plasma discharge tube. This magnetic field forms a variety of standing wave patterns depending on the physical dimensions of the plasma tube and the precise alignment of the optical resonant reflector. If the optical resonator is properly aligned, the laser emits laser light at the same time with any waveform to produce the TEMS.

TEMS is categorized by the number of black lines (nodes) appearing in the cross section of the laser beam. For example, if there is no black line in the cross section of the laser beam, it is classified as TEM00 mode. If there is one vertical line in the cross section, TEM01, three horizontal lines and two vertical lines, it is classified as TEM32. To achieve maximum power intensity, the resonant reflector should be aligned so that the laser can emit light in many modes at the same time. In this case, the mode pattern will consist of a combination of each individual TEM mode type.

Generally, the longer the laser and optics are, the more the mode pattern changes, resulting in an unbalanced laser shape and a power drop. In many cases, by adjusting the resonance reflector, the mode structure can be improved to increase the laser brightness. In some cases, however, it may not be possible for the lithography component to be drawn at the right timing (the lower the laser intensity, the slower the process), depending on the maximum laser power intensity that can be achieved.

5.2 Chemical theory of stereolithography

Stereolithography is made possible by a photopolymerization reaction where ultraviolet exposure changes the liquid resin monomer to a solid polymer. The extent to which the polymerization takes place depends on the total light energy absorbed.

Polymerization of liquid resins is not new technology and has been used for 20 years in many applications such as ultraviolet ink, coating, varnish, and coated circuit. However, the use of lasers as a source of light energy is a very recent innovation that has only begun and used only in basic academic research programs. The stereolithography process developed by 3D Systems is a whole new application.

[Photopolymer]

The photopolymer used in stereolithography consists of two basic materials. The first is a photoinitiator that forms a reactive radical species that absorbs laser energy and initiates the polymerization process. Photopolymers also include acrylated functionalized monomers and oligomers that undergo polymerization reactions when exposed to free radical groups.

Some polymers contain thermosetting materials that are sensitive to heat, which allows thermal curing of the final part. Overall, ultraviolet-curable polymers (UV-Curable polymers) do not polymerize to a noticeable extent after being cured by a laser and receiving heat. However, in the liquid form, polymerization reaction occurs uncontrollably when heated.

The photopolymer described above and the photopolymerization process described below will provide a basic overview of what is needed to better understand stereolithography. For more information on photopolymerization and photopolymerization, see UV curing volumes I and II. Editor, S.Peter Pappas, Science. Technology Marketing Corp. Norwalk Connecticut (1980).

[Light polymerization reaction process]

The following series of events take place during the photopolymerization process.

[Photoinitiators]

The photoinitiator molecule (PI) absorbs ultraviolet light from the laser and changes into an excited state (singlet state ¹ P1 *). This single high energy group quickly changes to a low energy excited state (triplet ³ Pl *) as shown in FIG. 35.

[Basic Radical Group (R.)]

The excited ³ P1 * molecules catalyze the formation of one or more (usually one) group called the primary radical (R *).

[Polymer Chain]

The raw radical reacts with the acrylic monomer to form a new radical group (RM). This reaction initiates a chain propagation process (polymerization) which is repeated over and over to form a polymer chain.

[Solidification]

The molecular weight of the polymer increases sharply until it becomes solid. If light energy is removed, the reaction will stop immediately. The reaction will gradually slow down and eventually stop as the available monomer concentration decreases.

The total dimension (depth, area) of the solid polymer formed when the ultraviolet laser is focused on the surface of the photopolymer is controlled by the intensity of the laser beam and the exposure time. Long exposure times and increased laser energy increase the depth and width of the solid region.

[Physical properties of photopolymer]]

Desolite SLR800 liquid, physical properties as gas are as follows.

[Liquid Properties]

Viscosity (Brook field cps at 25 ° C) 1350 centipoise

Solid (Reactive) 99 percent

Low volatility

[Characteristics of solid (after curing)] [

Extractables (with MEK solvent) 5%

Tensile modulus 140 kpsi

Tension size 6.7kpsi

Tensile elongation at break 7%

Plastics prepared using SLR 800 resin are fragile after UV curing. However, the hardened plastic can be carefully polished, sanded, sandblasted and drilled.

The surface of the finished part can be as smooth as we do by UV curing a thin layer of diluted resin (which is a 1: 1 mixture of MEK and resin) after polishing.

Defective parts (rupture, sculpture and holes) of components can be removed using similar resin / UV curing techniques.

The finished product shows the typical adhesion properties of acrylic. It is therefore possible to use standard epoxy glue for the connection of the two parts. One of the best glue so far is the resin itself which is cured by ultraviolet rays.

[Viscosity]

As can be seen in FIG. 36, relatively small changes in temperature result in large changes in liquid resin viscosity. That is, as the temperature increases, the viscosity decreases and as the temperature decreases, the viscosity increases. The drop in high temperature and viscosity causes the liquid to dilute and thus settle quickly during settling and quickly drain during subsequent processing.

It is preferred that a high temperature treatment is to be carried out while the structural coupling force of the component is minimized while the component is being produced so that the liquid resin may be polymerized uncontrollably.

5.3 Bullets, Banjtops and Work Curves

[Blit]

The ultraviolet laser beam focused on the surface of the photopolymer solidifies or cures a small liquid volume of the liquid. This characteristic can be explained as follows.

As shown in the intensity profile of the laser beam in FIG. 37, a large value represents a high luminous intensity, varies with the point, and the maximum value is near the center of the beam. The liquid can be thought of as consisting of a very thin horizontal sheet, which will absorb a portion of the laser beam (for example about 1/2) and the remainder will be transferred to the next underlying sheet. If the laser beam illuminates the liquid vertically for one second and the X unit light is incident on the top sheet during that time, the sheet absorbs by X / 2 units and the remainder is delivered to the next sheet. The third sheet is passed by X / 4 units and this process continues. The more light is absorbed, the better the polymerization will occur, so the top sheet will be solidified, the more it goes down to the next sheet, the less solid it forms, The phenomenon will happen. If the solid plastic is pulled out of the liquid, this final sheet remains because the bond strength of the solid plastic is not greater than the bond force of the liquid below.

The cured plastic depth changes as X increases and decreases and changes across the width of the laser beam as the front of the beam is not constant (as shown in the intensity profile). Therefore, since the center of the beam is the region having the highest intensity, it is hardened to the largest depth and the portion around the center of the beam can be hardened to a depth less than the center of the beam. The maximum solid depth obtained after curing is called the cure depth.

There is another second element that affects the shape of the blit. Because the refractive index of the solid plastic is slightly higher than the refractive index of the liquid, the laser light will be refracted inward as the liquid changes in its solidity. At some angle the light will refract from the boundary. This characteristic shown in FIG. 38 provides a narrower shaped blit than when considering only the intensity of the beam.

[Step period]

A blit is a building block of a stereolithography in which a continuous, blit-like overlap forms a line and a superposition of lines forms a surface. As described above, the shape of the blit greatly depends on the profile of the beam and the optical effect. That is, the total dimension is determined by how much energy is injected into the liquid - called exposure. Exposure is proportional to the product of the laser intensity and the step period, and is an operating parameter that determines the increment of the laser motion time when the line is formed, to several tens of microseconds. Thus, the stepper cycle is a measure of the time that the laser focuses on a particular position and the shorter transit time it takes to move to the next position.

Measurements of the actual blit produced by SLA-1 show that not only the dimensions of the blit are changed, but also the large step duration (5-4000 mils available) affects the shape of the blit. The relative dimensions according to the sample wipe shape and the various step periods are shown in FIG.

[Step size]

As shown in FIG. 40, the blits overlap to form a line. The distance that the laser travels while forming the blit is a paramater known for its step size. If the step size is less than or equal to the maximum diameter of the blit (i.e., measured across the top of the blit), the blit will overlap and a continuous line will be formed. Depending on the step size selection, many points along the path of the line drawn in the liquid are exposed for more than one step period. These points will be hardened more than the surrounding points as shown.

[Bonding and over lap]

The thickness of the line is the cumulative hardening depth of the blits forming the line. The thickness of the top line is greater than the spacing between layers (layer thickness) so that the layers in the successive layers are vertically superimposed when the lines are bonded or bonded together.

The bond between the layer and the layer occurs because the lower layer is close enough to the surface to absorb light and harden while the top layer is being formed. Thus, chemical bonding takes place between the underlying layer and the most recently formed top layer.

Bonding between strong layers and layers Thus, sufficient overlap is necessary for strong part formation. The important point is that excessive overlap causes the layer to twist. A typical overlay of 6 to 8 mils is adequate, with a layer thickness of 5 to 30 mi1s.

[Work curve]

To get the proper overlap, you need to know which step cycle value produces what hardening depth. It is also necessary to know the line widths produced under different stepperiod values, especially when determining the angle of the slopes that require skinfills to form a thin vertical wall to eliminate gaps.

[Work curve definition]

The work curve is a graph showing the line height and line width as a function of the step period value. As shown in Figure 41, this relationship is not linear but algebraic. That is, if the step cycle is multiplied by X, the line height and width of the step period increase by X times, but not much more than X times.

The work curve shows that the number of step cycles is somewhat less than a straight line when plotted against the line height or width. Thus, one line is tailored to obtain a linear equation representing a roughly constant relationship to the line height and width of the step period value for one point.

[Variables affecting the work curve]

Some variables affect the intersection and slope of the work curve. Various other resins exhibit different sensitivities to the ultraviolet light of the laser. The laser power is also dependent on the SLA and varies from day to day in the same SLA. Finally, the degree to which the laser is focused on the liquid surface (ie, whether the optics are well aligned or clean) affects the work curve.

[Calculate data for work curve]

Line height and width data for various step period values using specific resins and lasers are obtained by the generation and measurement of very small single layer components called benzotrapes. The benzotope is created on the liquid surface and has no elevator platform attached. As shown in FIG. 42, the benzotap forms five lines using a fixed step size 2 and a different step period.

The heights and widths of the lines were measured after the benzo top was drained and subsequently cured. In order to evaluate the wide range of the step cycle, two benztops were created with one step cycle being used on both sides. The SLA allows 5 to 4000 step cycles. One benzot tower was built with step cycles of 2560, 1280, 640, 320, and 160, and the other benzotopes were built with step cycles of 160, 80, 40,

[Measurement of Benzo top row]

Utility manual Optional MAKE TEST PART. To draw a benzotope. Measure the height and width of the benzo top line as follows.

Step 1) Place the benzopod so that the upper surface is visible on the measuring microscope or noncontact measuring device.

Step 2) The first line to be measured is perpendicular to the axis of the stage motion, and the center of the line is the midpoint of the visible part of the eye.

Step 3) Move the measuring platform so that the crosshair is centered at one end of the line. It is placed in the middle of the crossing rhythms. Note that in order to minimize the effect of backlash in the screw position setting, the measuring platform must be moved to a position where the measurement is in one direction.

Step 4) Zero the counter to measure the movement of the measuring zone or record the position of the measuring zone.

Step 5) Move the measuring platform and record the value so that the crosshair is at the end of the line. If the measuring table has moved too far, go back past the correct position and try again.

Step 6) Repeat steps 2 to 5 to measure the width of the remaining lines. The line width data for the step cycle is compiled.

Step 7) Fix the first benzopod to be on the short side and repeat steps 2 to 5 to measure the line height. After measuring, cut each line to make the next line appear.

Step 8) Repeat Step 7 for the remaining lines. Record the line height data for the step period value in the table.

[Calculation of sample work curve]

Enter the measured data from the benzo top using the utility menu MATERIAL MANAGER. Using the least squares method, the data points are approximated to one line to calculate the slope and Y intercept of each line.

Using the slope of the work curve and the Y intercept, you can write the line height and width equation for the step period. This equation is as follows.

(1) height = slope log SP + Y intercept,

SP = 10 ^{((height-Y intercept) / slope)}

(2) Width = slope log SP + Y intercept,

SP = 10 ^{((width-Y intercept) / slope}

As an example of how the MATERIAL MANAGER uses these equations, we will look for an accurate step cycle for a layer thickness of 20 mils. Keep in mind that for proper adhesion between layers, the cure depth should be 26 mils. Use the slope of the height curve 13.76 and Y intercept -6.50. Using the second equation of equation (1), the appropriate step cycle is found as follows.

SP = 10 ^{((26.00 + 6.50) /13.76)}

= 10 ^2.36

= 230

Calculate the line width at 230 step cycles using the first equation of equation (2).

Assume that the width curve is slope 6.52 and Y intercept 2.91.

Width = 6.52 log 230 + 2.91

= 6.52 (2.36) + 2.91

= 18.3 mils

Line width is useful when you need to know the surface angle of the skin to eliminate gaps between layers when designing an approximate flat surface.

It is also important when the step period is calculated for the skin vector. The skin vectors are spaced 1 to 4 mils apart and overlap each other a lot (for example, if the gap between the skins is 2 mil in 8 mil width, it will be exposed by overlapping 4 times). Thus, to obtain the desired skin thickness, the step period value for a single line of this thickness should be reduced by the ratio of line width to fill vector spacing. For example, for a 2 mil interval, the ratio is 8/2 = 4.

[Reconcile work curve]

Normal work curves are made only once to examine the resin type, laser and optical properties. However, since the laser power changes, it is necessary to measure the current power before making the part. The pre-menu option RANGE MANAGER is used to update the step cycle value in the .R range file when the laser power is changed.

Term Description

Claims (28)

In an improved stereolithographic apparatus, tailored object defining data for a three-dimensional object to be formed, said fitting data comprising a down-facing surface of the object during formation, - designating an enlogated support structure that extends over a plurality of layers to support the three dimensional object and automatically form the three dimensional object and the support structure in accordance with the fitting data; Wherein the second means comprises a second means. 2. The improved stereo lithographic device of claim 1, wherein the fitting data specifies that the web spans a downward cross section of the object. 2. The improved stereolithographic apparatus of claim 1, wherein the alignment data designates a support to hold the layer boundaries in place until a cross-hatch vector is drawn. 2. The improved stereolithographic apparatus of claim 1, wherein the alignment data designates a support for preventing deformation of the cantilevered portion of the object. 2. The improved stereolithographic apparatus of claim 1, wherein the alignment data designates a support for adhering layer sections to be drifted if not adhered. In an improved stereo lithography method, an object definition data for fitting to a three-dimensional object to be formed, the fitting data specifying an extended support structure extending over a plurality of layers to support the downward surface of the object during the formation process Using the fitting data to stereolithographically form the three-dimensional object and the support structure, and removing the support structure from the object after formation of the object The method comprising the steps of: 7. The method of claim 6, wherein the providing step comprises data specifying that the web is laid over a lower cross-section of the object. 7. The method of claim 6, wherein the providing step comprises data specifying a support to hold the layer boundary in place until a cross-hatch vector is drawn. 7. The method of claim 6, wherein the providing step comprises data specifying a support for preventing deformation of the cantilever portion of the object. 7. The method of claim 6, wherein said providing step comprises data specifying a support for adhering a layer section to be floated if not adhered. A stereolithographic method of forming a three-dimensional object, the method comprising: providing data representing the three-dimensional object to be formed; defining an area in which a plurality of support structures are to be provided; Obtaining data representing the plurality of support structures by a computer programmed to obtain data representing the plurality of support structures, merging the object data and the support data together to produce build data, And using the building data to form the three-dimensional object and the support structure from a plurality of integrated cross-sections. A stereolithographic method for forming a three-dimensional object, comprising: providing data representing the three-dimensional object to be formed; providing data indicative of a support structure for use in forming the three-dimensional object; Slicing data representing the support structure to obtain cross-sectional support data representative of the structure, and slicing the object data and section support data to form the three-dimensional object and the support structure from a plurality of integrated cross- Wherein the step of using the stereolithographic method comprises the steps of: A stereolithographic method for forming a three-dimensional object, the method comprising: providing data representing a three-dimensional object to be formed, wherein each cross-section comprises a boundary region and an internal region, A portion of the boundary region and the interior region of the cross-section is down-facing during the formation of the three-dimensional object, and a portion of the downwardly-facing internal region of the cross-section of the three- And using the object data and the support data to form the three-dimensional object and the support structure from a plurality of integrated cross-sections, wherein the continuously formed cross- Formed on previously formed sections (successively formed cross-sections are formed above previously for med cross-sections, stereo lithographic methods. 14. The method of claim 13, wherein the object is formed from a medium that can solidify as it is exposed to a predetermined stimulus, and wherein the utilizing step comprises providing a flowable medium in preparation for forming a continuous cross- And exposing the layer with a selected stimulus to form and adhere successive sections of the object and support structure. ≪ Desc / Clms Page number 13 > 15. The stereolithographic method of claim 14, wherein the medium is a photopolymer and the selected stimulus is selected from the group of visible, invisible, or ultraviolet light. A stereo lithographic apparatus for forming a three-dimensional object, comprising: means for providing data representing a three-dimensional object to be formed; means for defining a region in which a plurality of support structures are to be provided; A computer programmed to obtain data indicative of the plurality of support structures for generating the building data, means for merging the object data and the support data together to produce construction data, and means for merging the three- And means for utilizing the building data to form the support structure. A stereo lithographic apparatus for forming a three-dimensional object, comprising: means for providing data representing a three-dimensional object to be formed; means for providing data indicative of a support structure for use in forming the three- Means for slicing data representing the support structure to obtain cross-sectional support data indicative of a support structure, and means for slicing data representing the support structure from the plurality of integrated cross- And means for utilizing the support data. A stereolithographic apparatus for forming a three-dimensional object, comprising: means for providing data representative of a three-dimensional object to be formed, the cross-section including a boundary region and an inner region, Means for providing data indicative of a support structure for use in supporting a portion of said downwardly internal region of a section of said three-dimensional object when said three-dimensional object is being formed; And means for utilizing the object data and support data to form the three-dimensional object and the support structure from a plurality of integrated cross-sections, wherein the successively formed cross-section comprises a stereolithographic Device. 19. The method of claim 18, wherein the object is formed from a medium that can solidify as it is exposed to a predetermined stimulus, and wherein the utilization means forms a layer of a flow medium in preparation for forming a continuous cross- And means for exposing said layer to a selected stimulus to form and adhere successive sections of said object and support structure. 20. The stereolithographic apparatus of claim 19, wherein the medium is a photopolymer and the selected stimulus is selected from the group of visible, invisible, or ultraviolet light. 12. The method of claim 11, wherein the object is formed from a medium that can be solidified as it is exposed to a predetermined stimulus, and wherein the utilizing step comprises providing a flowable medium in preparation for forming a continuous cross- And exposing the layer with a selected stimulus to form and adhere successive sections of the object and support structure. ≪ Desc / Clms Page number 13 > 22. The stereolithographic method of claim 21, wherein the medium is a photopolymer and the selected stimulus is selected from the group of visible, invisible, or ultraviolet light. 13. The method of claim 12, wherein the object is formed from a medium that can be solidified as it is exposed to a predetermined stimulus, and wherein the utilizing step comprises providing a flowable medium And exposing the layer with a selected stimulus to form and adhere successive sections of the object and support structure. ≪ Desc / Clms Page number 13 > 24. The stereolithographic method of claim 23, wherein the medium is a photopolymer and the selected stimulus is selected from the group of visible, invisible, or ultraviolet light. 17. The method of claim 16, wherein the object is formed from a medium that can solidify as it is exposed to a predetermined stimulus, and wherein the utilizing means forms a layer of a flow medium as a preparation for forming a continuous cross-section of the object and the support structure And means for exposing said layer to a selected stimulus to form and adhere successive sections of said object and support structure. 26. The stereolithographic apparatus of claim 25, wherein the medium is a photopolymer and wherein the selected stimulus is selected from the group of visible, invisible, or ultraviolet light. 18. The method of claim 17, wherein the object is formed from a medium that can solidify as it is exposed to a predetermined stimulus, and wherein the utilization means forms a layer of a flow medium in preparation for forming a continuous cross- And means for exposing said layer to a selected stimulus to form and adhere successive sections of said object and support structure. 28. The stereolithographic apparatus of claim 27, wherein the medium is a photopolymer and wherein the selected stimulus is selected from the group of visible, invisible, or ultraviolet light.