JPH0236927A - Method and device for preparing three-dimensional body - Google Patents

Abstract

PURPOSE: To produce a three-dimensional object without the need of producing design layouts and drawings, and of producing drawings and tool for processing by applying energy such as a spot of UV light or the like as a graphic pattern to a working surface of a fluid medium to form thin, solid, individual layers on the surface for programming under the control of a computer or the like. CONSTITUTION: A three-dimensional object is generated by creating a cross-sectional pattern of the object to be formed on a surface of a fluid medium capable of altering its physical state in response to synergistic stimulation. Adjacent laminae, representing successive adjacent cross-sections of the object, are automatically formed and integrated together to provide a step-wise layer buildup of the object, whereby a three-dimensional object is formed and drawn from a substantially planar or sheet-like surface of the fluid medium during the forming process. Complex forms are more easily created by using the functions of a computer to help generate programmed commands and to then send the program signals to a stereolithographic object forming system.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to improvements in methods and apparatus for forming three-dimensional objects from a fluid medium, and in particular, for forming three-dimensional objects quickly, reliably, accurately and economically. It relates to three-dimensional modeling that applies lithography to the production of three-dimensional objects.

[Conventional technology]

When manufacturing parts made of plastic, it is common to first design the part and then painstakingly create a prototype of the part. All of these require considerable time, effort and expense. This design is then reviewed, and this laborious process is often repeated many times until the design is optimal.

After the design is optimized, the next step is its manufacture. In most production, plastic parts are injection molded. Because the design time and tooling costs are so high, injection plastic parts are usually only practical in high volume production. Other methods such as direct machining, vacuum forming and direct molding can be used to manufacture plastic parts. However, these methods are typically cost effective only for short runs of production, and the parts produced are of inferior quality to injection molded parts.

Recently, very good methods have been developed to create three-dimensional objects in a fluid medium. The fluid medium is selectively stiffened by a beam of radiation selectively focused at predetermined points of intersection within a three-dimensional volume of the fluid medium. A typical example of an apparatus for forming such three-dimensional objects is U.S. Pat. No. 2,775,78.
No. 5, No. 4041.476, No. 4,078,229
No. 4,238,840 No. 4,288,861
No. JP-A-56-144478, Hideo Kodama, "Automatic creation of three-dimensional shapes as a method for displaying three-dimensional information" (Transactions of the Institute of Electronics and Communication Engineers, VOL, J64-C No. 41981)
(April), l1ideo Kodama, Auto
maticmethod for fabricati
D a three-dimensional Plus
tic model with photo-hard
ening polymer.

Review of 5 scientific instruments
ruments, 52(11).

Nov, 1981, and Alan J, Herb.
ert, 5solidObject Generation
on, Journal of' Applied
Photograpl + Lc Engineering
, VOL 8. No, 4. August 1982. All of these devices use various large-scale multiple beam schemes to deliver synergistic energy at a selected point deep within the fluid volume to the exclusion of all other points within the fluid volume. It relies on giving. In this regard, various conventional systems use a pair of electromagnetic radiation beams oriented such that they intersect at specific coordinates. in this case,
The various beams may have the same or different wavelengths, or the beams may intersect the same point sequentially rather than simultaneously. However, in all of these cases, only the intersection points of the beams are energized to an energy level sufficient to accomplish the curing process necessary to form a three-dimensional object within the volume of fluid medium.

(Problems to be Solved by the Invention) Unfortunately, however, such a three-dimensional molding apparatus has many problems in terms of resolution and exposure control. The reduction in radiation intensity as the point of intersection moves deeper into the fluid medium, and the reduction in resolution for imaging the focused spot, naturally result in complex control conditions. Absorption, diffusion, dispersion and analysis methods all
Making it difficult to process deep within a fluid medium economically and reliably. Therefore, it was difficult to form extremely thin layers, and automatic lamination was also difficult.

But to be able to move quickly and reliably from the design stage to the prototype stage and then to final production. In particular, the ability to go directly from computer-based design to the prototype virtually immediately for such plastic parts, as well as the long-standing desire for equipment to mass-produce them economically and automatically, has brought new challenges to the field of design and manufacturing. Still.

Therefore, those involved in the development and manufacturing of three-dimensional plastic objects, etc. can move from the design stage to the prototype stage to manufacturing while avoiding the complex focusing, alignment and exposure problems of conventional three-dimensional manufacturing equipment. It has been recognized that it would be desirable to further develop a more rapid, reliable, economical, and automatic means for rapid transfer. This invention satisfactorily meets all these needs.

SUMMARY OF THE INVENTION The present invention provides successive adjacent cross-sectional layers of this object on the surface of a fluid medium capable of changing its physical state in response to appropriate synergistic energy. A new and improved apparatus for creating three-dimensional objects by forming plates is provided. Successive laminates are automatically tightly integrated as they are formed to form the desired three-dimensional object.

By way of example, and not by way of limitation, in the presently preferred embodiment, the invention utilizes computer-generated graphical ideas in combination with lithography. In other words, in order to apply lithography (modeling) technology to the manufacture of three-dimensional objects and directly manufacture three-dimensional objects from computer instructions, computer-assisted design (CAD) and computer-assisted design are necessary. Manufacturing borrowed from (C
AM) are executed simultaneously. The invention can be used for forming models and prototypes in the establishment phase of product development, or as a manufacturing device, or for the formation of purely artistic objects.

As used herein, "stereolithography" refers to methods and apparatus for making objects by "printing" thin layers of curable material, such as infrared ray curable material, on top of each other.

A moving spot beam of programmed UV light that illuminates a surface or layer of a UV (ultraviolet) curable liquid is used to form a solid cross section of an object on the surface of the liquid. after that,
The object is moved away from the surface of the liquid by -layer thickness in a programmed manner, after which the next cross-section is formed and adhered to the immediately previous layer to form the object. Continue this process until the entire object is formed.

By means of the method of the invention, virtually any form of object can be formed. Complex shapes are made easier to create by using computer functions to generate program instructions and then send program signals to the stereolithography device.

Of course, other types of treatments for the curable fluid medium, such as particle irradiation (e.g. electron beam), spraying of material through a mask, or chemical reactions by ink jets, or non-ultraviolet incidence/radiation. It would not be outside the scope of the invention to practice this invention using suitable synergistic energies.

By way of example, in practicing the invention, a body of fluid medium capable of solidifying in response to a predetermined energy may first be contained in any suitable container to form successive cross-sectional laminates therein. Confining selected working surfaces of the fluid medium such that

Thereafter, synergistic energy of a suitable type, such as a spot of ultraviolet light, is applied in a graphic pattern to a specified working surface of the fluid medium to form a thin, solid, discrete layer on this surface. As they are formed, successive adjacent layers, each layer representing an adjacent cross-section of the three-dimensional object to be created, are automatically superimposed on each other to unite the layers and form the desired three-dimensional object. form. In this point,
When the fluid medium has hardened and the solid material has been formed as a thin laminate on the working surface, the first laminate or a suitable fixed platform is activated by any suitable actuating device, typically all microcomputer etc. under the control of, and moved away from the work surface in a programmed manner. In this way, the solid material initially formed on the working surface is moved away from this surface, and new liquid flows into the position of the working surface. A portion of this new liquid is converted into a solid material by a programmed UV light spot to define a new laminate, which is adhesively joined to the material adjacent to it, ie the immediately previous laminate. This process continues until the entire three-dimensional object is formed. After this, the formed object is removed from the container and the device is ready to create another object identical to the first object, or an entirely new object generated by the computer.

The stereolithography method and apparatus of the present invention has many advantages over methods currently used to create plastic objects. That is, the method of the present invention does not require the creation of design layouts and drawings, or the creation of processing drawings and tools. Setting: One person can work directly with the computer and stereolithography equipment, and when satisfied with the design displayed on the computer output screen, can manufacture parts for direct inspection. If the design has to be modified, this can be easily done through a computer and then another part can be made to verify that the design changes were correct. By design,
If you need several parts with interacting design parameters, you can quickly change the entire design of the part and recreate it.
The method of the present invention is further advantageous because the entire assembly can be made and tested repeatedly if necessary.

After the design is complete, manufacturing of the parts can begin immediately, avoiding weeks or months of turnaround time between design and manufacturing. The final production rate and cost of parts should be similar to current injection molding costs for short run production, with labor costs even lower than for injection molding. Injection molding is economical only when large numbers of identical parts are required. Three-dimensional manufacturing is useful for short production runs, as no tooling is required and production set-up time is very short. Similarly, design changes and custom parts are easily obtained using this method. Because the parts are easy to manufacture, stereolithography allows the use of plastic parts in many places where parts of metal or other materials are currently used. Furthermore, a plastic model of the object can be made quickly and economically before a decision is made to make parts of expensive metal or other materials.

Therefore, the three-dimensional modeling method and apparatus of the present invention are a CAD or CA system that can quickly, reliably, accurately, and economically install and manufacture two-dimensional plastic parts.
It responds to a long-standing need for an M system.

The above and other objects and advantages of the present invention will become apparent from the detailed description of the drawings below.

〔Example〕

The invention will now be described in detail with reference to the drawings.

FIGS. 1 and 2 are flowcharts showing the basic method and apparatus of the present invention for creating a three-dimensional object by stereolithography.

Fixed weights can be removed by other types of synergistic energy such as ultraviolet (UV) irradiation, electron beam visible light, non-visible light irradiation, ink jets or reactive chemicals applied through a suitable mask. A number of liquid state chemical agents are known that can be induced to transform into coalescent plastics. UV-curable chemicals are currently used as inks in high-speed printing, as adhesives in coating processes for paper and other materials, and as adhesives in coating processes for paper and other materials.
as well as other specialized fields.

Three-dimensional modeling is a technology that reproduces graphic objects using various methods. Current examples include photocopying, xerography, and microengraving, such as those used in the manufacture of microelectronic circuits. Computer-generated graphics displayed on a plotter or cathode ray tube are also in the lithographic form, and the image is a computer-encoded image of the object.

Computer-aided design (CAD) and computer-aided manufacturing (CAM) are techniques that apply the power of computers to the design and manufacturing process.

A typical example of CAD is in the field of electronic printed wiring design. In this case, the computer and plotter draw the printed circuit board design once the design parameters are given as data inputs to the computer.A typical example of a CAM is a numerically controlled milling machine, given appropriate programming instructions. Then, a computer and a milling machine process the metal parts. C
Both AD and CAM are important and rapidly growing technologies.

The main purpose of this invention is to leverage computer-generated graphic ideas in combination with UV-curable plastics to simultaneously execute CAD and CAM to create three-dimensional objects directly from computer instructions. It is. This invention is called three-dimensional modeling, and can be used to form templates and prototypes at the design stage of product development, as a manufacturing device, or as artistic forms.

FIG. 1 broadly explains the three-dimensional modeling method of the present invention. Step 10 in FIG. 1 represents the creation of individual laminates representing the cross-sections of the three-dimensional object to be formed. Step 11, which is typically only performed if step 10 has been performed correctly, combines adjacent laminates formed in succession to form the desired three-dimensional object as programmed in the device. , selectively curing. For this reason, the three-dimensional modeling apparatus of the present invention is capable of using incident radiation, electron beam, other particle irradiation, ink jet,
or a fluid medium capable of changing its physical state, respectively, in response to appropriate synergistic energy, such as a chemical agent applied by spraying through a mask adjacent to the surface of the fluid, e.g. UV curing. A three-dimensional object is created by creating a cross-sectional pattern of the object to be formed on a selected surface of a liquid, etc. successive adjacent laminates representing successive adjacent cross sections of the object are automatically formed;
They are integrated to create a graded layered or laminar configuration of objects, and during such forming steps, three-dimensional objects are formed and lifted from a generally planar or sheet surface of the fluid medium.

The method described above is described in more detail in FIG.

In FIG. 2, step 12 requires containing a fluid medium capable of solidifying in response to a predetermined reactive energy. Step 13 applies this energy in a graphical conflict pattern to a selected fluid surface to form a thin, solid, discrete layer on that surface. Each layer represents an adjacent cross section of the three-dimensional object being created. It is desirable that each such layer be made as thin as possible while practicing this invention to maximize the resolution and accurate reproduction of the three-dimensional object being formed, as well as to reduce fabrication time. For this reason, an ideal theoretical situation would be such that the object is made with only selected working surfaces of the fluid medium, resulting in an infinite number of laminates, each with a thickness less than zero. The hardened depth is only slightly larger (e.g. 1 mm
(below). By forming such a thin layer, the accuracy of the formed object can be improved, and it is also possible to form a molded part without a support on the surface. Of course, when this invention is used in practice, each laminate is a thin laminate, but suitable bonding is required when bonding to adjacent laminates to form a cross-section and define other cross-sections of the object being formed. The thickness should be such that it has the properties.

In step 14 of FIG. 2, successive adjacent layers or laminates are superimposed on each other as they are formed to integrate the various layers and form the desired three-dimensional object. In the normal practice of this invention, when the fluid medium is cured and the solid material is formed to form a laminate, the laminate is moved away from the working surface of the fluid medium and the previously formed laminate The next laminate is formed in the new liquid replacing the laminate, so that each successive laminate is superimposed with every other cross-sectional laminate (by the natural adhesive properties of the hardened fluid medium) and becomes integral. Become. For this reason, the process of producing such cross-sectional laminates is repeated many times until the entire three-dimensional object is formed. The object is then removed and the device is ready to manufacture another object. This object may be the same as the previous object, or it may be made into a completely new object by replacing the program controlling the three-dimensional modeling device.

3 to 8 illustrate various apparatuses suitable for carrying out the three-dimensional modeling method illustrated in the flowcharts of FIGS. 1 and 2.

As previously mentioned, "stereolithography" is a method and apparatus for making solid objects by "printing" thin layers of curable material, such as UV curable material, one after the other, one on top of the other. UV illuminating the surface or layer of a UV curable liquid
Using a programmed moving spot beam of light,
Forming a solid cross section of an object on the surface of a liquid. After this, in a programmed manner, the object is moved away from the surface of the liquid by -layer thickness, forming the next cross-section and bonding with the previous layer to define the object. Continue this process until the entire object is formed.

With the method of the invention, virtually any type of object can be shaped. Complex shapes can be created more easily by using the power of a computer to generate program instructions and send the program signals to a stereolithography device.

A three-dimensional modeling apparatus according to a presently preferred embodiment is shown in a side sectional view in FIG. The container 21 is filled with a UV curable liquid 122 or the like, and a selected work surface 23 is defined. A programmable source such as ultraviolet radiation 26 creates an ultraviolet spot 27 in the plane of surface 23. Movement of a mirror or other optical or mechanical element (not shown) that is part of the light source 26 may cause the spot 27 to move across the surface 23. The position of spot 27 on surface 23 is controlled by a computer or other programming device 28. A movable lifting platform 29 inside the container 21 can be selectively raised and lowered. The position of the platform 29 is controlled by a computer 28. When this device operates, 30a, 30b
, 30c, a three-dimensional object 30 is formed by stacking the integrated laminates step by step.

The surface of the UV curable liquid 22 is kept at a constant height within the container 21 and a spot 27 of UV light or other suitable type of UV light of sufficient intensity to cure the liquid and convert it into a solid material is applied. reactive energy is transferred across the work surface 23 in a programmed manner. When the liquid 22 hardens to form a solid material, the lifting platform 29, which was initially just below the working surface 23, is lowered from this working surface in a programmed manner by means of a suitable actuator. In this way, the initially formed solid material comes to be below the surface 23 and the new liquid 22 flows into the surface 23. A portion of this new liquid is converted into a solid material by the programmed UV light spot 27, and this new material is adhesively joined to the underlying material. three dimensional objects 30
Continue this process until the whole is formed. after that,
Object 30 is removed from container 21 and the apparatus is ready to make another object. Thereafter, another object can be created, or by replacing the program on the computer 28, a new object can be created.

The curable liquid 22, such as a UV curable liquid, must have several important properties.

(A) This is done so that a practical object formation time can be obtained.
It must cure quickly with available UV light sources. (
B) Must be adhesive so that successive layers adhere to each other. (C) Its viscosity must be low enough so that when the platform moves the object, fresh liquid material flows quickly to the surface. (,D) Should absorb UV so that the layer formed is reasonably thin.

(E) a UV-curable liquid and a partially cured liquid that is reasonably soluble in a solvent in the liquid state and reasonably insoluble in the same solvent in the solid state, after the object has been formed; must be able to be washed off. (F) Should be as non-toxic and non-irritating as possible.

The cured material must have the desired properties once it is in the solid state. These properties, like those of other plastic materials in general, are application-related. Color, texture, strength, electrical properties, flammability and flexibility are properties to consider. Furthermore, in many cases
Material cost is also important.

The UV-curable material used in the presently preferred embodiment of the practical stereolithography apparatus (e.g., FIG. 3) is Potting Polymer, a modified acrylate manufactured by LoctiLe!, TD. Compound (Potting Compound)
It is 363. A method for making this typical UV curable material is described in US Pat. No. 4,100,141.

That is, the UV curable materials described above can be cured by free radical copolymerization using a myriad of known initiators as free radicals. Such initiators include peroxides such as hydrogen peroxide; organic peroxides such as benzoyl methyl ketone peroxide; azo compounds such as 22'-azobis(isobutyronitrile); hydroperoxide,
Hydroperoxides such as t-butyl hydroperoxide, methyl ethyl ketone hydroperoxide;
Peresters that hydrolyze to peracid compounds such as t-butyl perbenzoate, t-butyl peracetate; photosensitive compounds such as benzophenone, benzoin ether, etc.The light source 26 forms the desired details of the object. A spot 27 of UV light is generated that is small enough to be able to cure, and strong enough to cure the UV curable liquid used as quickly as practical. The source 26 is configured to be turned on and off and can be programmed to move the focusing spot 27 across the surface 23 of the liquid 22.

Therefore, when the spot 27 moves, the liquid 22
is cured into a solid and draws a solid pattern on the surface in much the same way that a chart recording or drafting device uses a pen to draw a pattern on paper.

The light source 26 of the stereolithography apparatus of the presently preferred embodiment uses a 350 watt short arc mercury lamp located within the housing, and the light output of the housing is coupled to a 1 mm diameter UV transparent optical fiber bundle (shown in the figure). (not) focused at the edge. The end of the bundle near the mercury lamp was water cooled, and an electronically controlled shutter plate was provided between the lamp and the end of the bundle to turn the light through the bundle on and off.

The bundle was 1 m long and the light output was fed into a lens tube with a quartz lens to focus the UV to a spot. The light source 26 is capable of producing a spot slightly smaller than 1n+m in diameter and has a longwave UV intensity of approximately 1 Watt/Ca.

In the apparatus of FIG. 3, means are provided to keep the surface 23 at a constant height and to replenish this material after the object has been removed, so that the focal spot 27 remains sharply focused on a constant focal plane. , thus ensuring maximum resolution when forming thin layers along the working surface. In this respect, a focal point is formed to obtain a region of high strength on the working surface 23, which quickly diverges to a lower strength, limiting the depth of the curing process and creating the thinnest area suitable for the object being formed. Preferably, cross-sectional laminates are obtained. This is best accomplished by using a short focal length lens and placing the source 26 as close to the work surface as possible to maximize divergence in the focal cone entering the fluid medium. the result,
Resolution is substantially higher.

H-P manufactured by Heuret Paracard
A Model 9872 digital plotter (not shown) is used to move light source 26. Connect the lens tube to the plotter pen.
The plotter is driven by the computer 28, which is attached to the cartridge and uses conventional graphics commands. The shutter is controlled by a model H-P3497 data acquisition/control unit using computer commands.

Other physical forms of light source 26 or equivalents thereof may be used. Scanning can be performed using an optical scanner, thus eliminating the need for optical fiber bundles and digital plotters. Ultimately, UV lasers become a better light source than similar arc lamps. The speed of the stereolithography process is primarily limited by the intensity of the light source and the response of the UV curable liquid.

A lifting platform 29 is used to support and hold the object 30 being formed and to move it up and down. Typically, after one layer is formed, the object 30 is moved beyond the level of the next layer (overdip into the liquid medium) so that solids are left on the surface 23 where they have formed. Allow liquid 22 to flow into the temporary void and then return to the correct height for the next layer. As a result, the liquid 22 that has flowed into the cavity recedes like a receding tide, forming a layer of a predetermined thickness. This allows automatic lamination of extremely thin layers.

The requirements for the platform 29 are that it be able to move as programmed with reasonable speed and accuracy, and that it be strong enough to withstand the weight of the object being formed. Furthermore, manual fine adjustment of the position of the lifting platform is helpful during the setup phase as well as when removing objects.

The lifting platform 29 in the embodiment shown in FIG.
(not shown).

This plotter, under the program control of the computer 28,
H-P349 with internal digital to analog converter
Powered by a Type 7 data acquisition/control unit.

The computer 28 of the three-dimensional modeling apparatus of this invention basically has two functions. First, it helps the operator design a three-dimensional object in such a way that it can be created. Second, convert this design into appropriate commands for stereolithography and send these commands so that the object is formed. In some applications, a design of the object exists and the only action of the computer is to issue appropriate commands or commands.

In the ideal case, the operator can design an object and view it in three dimensions on the CRT screen of computer 28. When the operator completes the design, he commands the computer 28 to create the object, and the computer issues appropriate commands for three-dimensional modeling.

In a practical example of this invention, the computer 28 is H-
P9816 and uses the basic operating system. A typical program is shown in the attached reference material. In this system, the operator
- Program using Graphic Language (command structure for 3497A) and Basic Language commands. The operator must also set the appropriate exposure time and speed for the UV curing time. In order to operate this device, we create an image of the object and write a program to drive the three-dimensional modeling device to create this object.

The drive for the lifting platform 29 may be mechanical, pneumatic, hydraulic or electrical, and optical or electronic circuit feedback may be used to precisely control its position. Lifting platform 29
are typically made of glass or aluminium, but
Any material to which the cured plastic material will adhere is suitable.

In some cases, the calculator 28 may be dispensed with; particularly if only simple shapes are to be built, a simpler dedicated programming device may be used. Alternatively, computer controller 28 may simply execute instructions generated by another, more complex computer. This is the case when some stereolithography devices are used to create an object and another device is used to initially design the object to be formed.

A constant level of liquid 22 at work surface 23 can be maintained using a computer-controlled pump (not shown). This necessity is due to the following reasons. That is, when the liquid is exposed to light, it contracts due to a change in its capacitance, and the liquid level changes.

Further, when the lifting table 29 moves into the liquid, the volume of the liquid changes, and thereby the liquid level changes. The thickness of the liquid layer is determined by the depth of the previous layer formed below the liquid level, so if the liquid level is not kept constant, the actual thickness of the layer formed will be less than the desired thickness. This is because the thickness of the layer differs from that of the other layer, and a layer with an accurate thickness cannot be formed. Suitable liquid level sensing devices and feedback circuits known in the art are used to drive a fluid pump or to drive a liquid displacement device to move the platform out of the fluid medium as it moves deeper into the fluid medium. A solid rod (not shown) can be driven to level out changes in fluid volume to maintain a constant fluid level on surface 23. Instead of this, the liquid level 22 sensing the light source 26
sharp focus on the work surface 23 automatically. All of these alternatives can be easily accomplished with common software working in conjunction with computer controller 28.

After the three-dimensional object 30 is formed, the lifting platform 29 is raised and the object is removed from the platform. Typically, after this, the object is cured in a solid medium, such as acetone, which does not dissolve it.
Ultrasonic cleaning in a solvent that dissolves the liquid state of the uncured fluid medium. The object 30 is then placed under an intense ultraviolet flood, typically a 200 watt/inch UV curing lamp, to complete the curing process.

Furthermore, several containers 21 can be used when practicing the invention. Each container contains a different type of curable material and can be automatically selected by the stereolithography device. In this case, the various materials may be plastics of different colors or may have both insulating and conducting materials available for the various layers of the electronic component.

Other embodiments of the invention will now be described with reference to the other drawings, where like reference numerals are used throughout the drawings to refer to parts similar to those described for the preferred embodiment of the invention shown in FIG. There is.

FIG. 4 shows another type of three-dimensional modeling apparatus. In this case, the UV curable liquid 22 etc. floats on top of the heavier UV transparent liquid 32. Liquid 32 is immiscible with and does not wet curable liquid 22. -For example,
Suitable intermediate liquid layer 32 is ethylene, glycol or heavy water. In the apparatus of FIG. 4, the three-dimensional object 30 is lifted out of the liquid 22 instead of penetrating into the fluid medium as shown in the apparatus of FIG.

A UV light source 26 in FIG. 4 focuses a spot 27 on the interface between liquid 22 and an immiscible intermediate liquid layer (mold release liquid) 32. The UV radiation passes through a suitable UV-transparent window 33 made of quartz or the like supported in the bottom of the container 21. The curable liquid 22 is provided as a very thin layer on top of the immiscible layer 32, thus limiting the depth of curing since ideally a very thin laminate should be produced. There is the advantage of directly limiting the layer thickness instead of relying solely on adsorption etc. For this reason, the formation area is more sharply defined, and if the apparatus shown in FIG. 4 is used, certain surfaces can be formed more smoothly than the apparatus shown in FIG.

Furthermore, the UV curable liquid 22 requires less volume;
It is easier to replace one curable material with another.

The device of FIG. 5 is similar to that of FIG. 3, but with a movable U
There is no V light source 26, instead of a programmed source 26 and a focused spot 27, a collimated wide UV
A light source 35 and a suitable aperture mask 36 are used. The aperture mask 36 is placed as close as possible to the work surface 23 and the UV source 3
The collimated light from 5 passes through mask 36 and
The working surface 23 is exposed, thus producing successive adjacent laminates, similar to the embodiment of FIGS. 3 and 4.

However, the fixed mask 36 representing the cross-sectional shape of the object to be formed
By using , a two-dimensional object with a constant cross-sectional shape can be obtained. When changing this cross-sectional shape, a new mask 36 for that particular cross-sectional shape must be replaced and properly aligned. Of course, by providing a web of masks (not shown) that is successively moved into alignment with the surface 23, the masks can be changed automatically.

FIG. 6 also shows a three-dimensional modeling apparatus similar to that previously described with respect to FIG. However, in place of the light source 26 and focal spot 27, a cathode ray tube (CRT) 38, a fiber optic faceplate 39 and a water or other template layer 40 are provided. Therefore, from the computer 28 to the CRT 38
The image provided to the tube forms an image on the UV emitting phosphor surface of the tube where it passes through the optical fiber layer 39 and the template layer 40.
The fluid medium 22 enters the working surface 23 . In all other respects, the apparatus of FIG. 6 forms successive cross-sectional laminates that define the desired three-dimensional object to be formed, just as in the previously described embodiments.

7 and 8 show a three-dimensional modeling apparatus in which the lifting platform 29 has additional degrees of freedom, allowing different sides of the object 30 to be exposed for other construction methods.

Similarly, this stereolithography method can be used as an "add-on" method, and the lift platform 29 can be used to pick up and position additional parts for supplementary stereolithography processing. In this respect, the apparatus shown in FIGS. 7 and 8 is the same as that shown in FIG. 3, except that in the apparatus of FIGS. It differs in that it has two degrees of freedom, or automatically controlled rotation. In this regard, FIG. 7 shows the adjustable lifting platform 29a in the normal position, and FIG.
A rotated platform 29a is shown, so that an additional auxiliary structure 41 formed by stereolithography can be selectively formed on one side of the three-dimensional object 30.

Practical stereolithography devices have additional components and subsystems beyond those described above for the devices shown schematically in FIGS. 3-8. For example, a practical device has a frame and housing and a control panel.

Additionally, there may be means for shielding the operator from excess UV and visible light, and for allowing the operator to view the object 30 while it is being formed. Practical equipment has safety measures to control ozone and harmful fumes, as well as high pressure safety protection and interlocking devices. Such practical devices also have a means of effectively shielding sensitive electronic circuitry from noise sources.

As already explained, many other devices can be used to carry out the three-dimensional modeling method of the present invention. For example, instead of UV light source 26, an electron source, visible light source, laser light source, short arc light source, high energy particle light source, X-ray source, or other radiation source may be used and is responsive to a particular type of reactive energy. Any suitable fluid medium, such as a photopolymerizable material, can be used. For example, alpha octadecyl acrylic acid, which has been slightly prepolymerized using UV light, can be polymerized using an electron beam. Similarly, poly(2,3-dichloro-1-propylene acrylate) can be polymerized using an X-ray beam.

〔Effect of the invention〕

The stereolithography method and apparatus of the present invention has many advantages over methods currently used for manufacturing plastic objects. The method of the present invention does not require the creation of design layouts and drawings, nor does it require the creation of processing drawings and tools. The designer can work directly with the computer and stereolithography equipment, and when satisfied with the design displayed on the computer's output screen, can manufacture the part for direct consideration. When a design needs to be changed, it can be easily done through a computer, and then another part can be made to verify that the change was correct. If a design requires several parts with interacting design parameters, the design of all parts can be quickly changed and recreated. The method of the invention is thus further advantageous because the entire assembly can be made and tested repeatedly, if necessary.

Once the design is complete, manufacturing of the parts can begin immediately, thus avoiding weeks or months between design and manufacturing. The final production rate and cost of parts should be similar to the cost of current injection molding for short run production, and labor costs can be even lower than with injection molding.

Injection molding is economical only when large numbers of identical parts are required. Stereolithography is useful for short-term production. This is because no tools are required and the production set-up time is very short. Similarly, design changes and custom parts are easily obtained using this method. Because the parts are easy to make, stereolithography allows the use of plastic parts in many places where parts of metal or other materials are currently used. Furthermore, a plastic model of the object can be made quickly and economically before a decision is made to manufacture parts of expensive metal or other materials.

Although various three-dimensional modeling devices for carrying out this invention have been described above, it is clear that they all share the idea of drawing a nearly two-dimensional surface and pulling up a three-dimensional object from this surface. .

This invention can quickly produce three-dimensional plastic parts, etc.
To meet a long-standing need for CAD and CAM equipment that can be designed and manufactured reliably, accurately, and economically.

While the invention has been illustrated and described in a particular form, it will be obvious that various modifications may be made within the scope of the invention. Therefore, the present invention is not limited only to the scope of the claims of the present application.

[Brief Description of the Drawings] Figures 1 and 2 are flowcharts showing the basic idea used to carry out the three-dimensional modeling method of the present invention, and Figure 3 is a flowchart showing the currently preferred apparatus for carrying out the invention. A block diagram combined with a cross-sectional view of a possible embodiment; FIG. 4 is a cross-sectional view of a second embodiment for carrying out the invention; FIG.
FIG. 6 is a sectional view of a third embodiment of the invention, FIG. 6 is a sectional view of a further embodiment of the invention, and FIGS. FIG. 4 is a partial cross-sectional view of a modified three-dimensional modeling apparatus shown in FIG. 3; 21... Container, 22... UV curable liquid, 23...
・Work surface, 26... Light source, 28... Calculator, 29.
...Lifting platform, 30...object. Applicant's agent Mr. Sato

Claims (1)

[Scope of Claims] 1. A device for directly creating a three-dimensional object designed and created by at least one computer, comprising: an arithmetic device that generates an image output; a computer-controlled device responsive to said image output; a computer-controlled device that automatically exposes said initial layer to curing radiation generated by said image output to form a thin cross-section of reactive fluid corresponding to said image output; a computer-controlled apparatus for automatically forming a three-dimensional object by adhering the next layer to the immediately preceding layer while being exposed to curing radiation; 2. The apparatus for forming a three-dimensional object according to claim 1, wherein the image output is formed by a CAD method. 3. The apparatus for forming a three-dimensional object according to claim 1, wherein the computer control device that automatically performs and repeats each step is a CAM system. 4. The device for forming a three-dimensional object according to claim 1, wherein at least one of the computer-controlled devices includes a moving device for supporting and moving the formed object. 5. At least one of the computer-controlled devices directs the fluid to the curing radiation X-Y on the work surface.
Apparatus for forming a three-dimensional object according to claim 1, comprising a surface exposing apparatus. 6. Apparatus for forming three-dimensional objects according to claim 1, wherein at least one of said computer-controlled devices controls the level of said fluid medium. 7. The apparatus for forming a three-dimensional object according to claim 4, wherein the moving device comprises an elevator. 8. Forming a three-dimensional object according to claim 4, further comprising a device for assisting the moving device with a rotation device that changes the direction of the object with respect to the work surface on which the layer is formed. device to do. 9. The device for forming a three-dimensional object according to claim 4, wherein the moving device has various degrees of freedom for movement. 10. The apparatus for forming a three-dimensional object according to claim 6, wherein the liquid level of the liquid medium is maintained constant. 11. An apparatus for forming a three-dimensional object according to claim 4, wherein the moving device moves the object away from the work surface and further into the fluid medium as the object is formed. . 12. Apparatus for forming three-dimensional objects according to claim 4, wherein said moving device moves said object away from said work surface and further withdraws said object from said fluid medium as said object is formed. 13. A device for directly creating a three-dimensional object designed and created by at least one computer, comprising: a computing device for generating an image output; a computer-controlled device that defines a cross-section, automatically forms a thin initial layer of reactive fluid, positions this initial layer of reactive fluid on a working surface, generates a next layer, and generates a next layer; a computer-controlled apparatus for automatically forming a three-dimensional object by adhering the next layer to the immediately preceding layer while being exposed to curing radiation; 14. A device for directly producing a three-dimensional object designed and created by at least one computer, comprising: a computing device for generating an image output, the image output defining a thin cross-section of the computer-designed three-dimensional object; a mold release liquid positioned between the work surface and the bottom of the container; and automatically forming a thin initial layer of the reactive fluid and positioning the initial layer of the reactive fluid on the work surface. a computer-controlled device; and exposing the initial system of reactive fluid to curing radiation generated in response to the image output through the bottom of the container and the release agent to form a reactive fluid corresponding to the image output. a computer-controlled device that forms a thin cross-section of the three-dimensional object; and a computer-controlled device for automatically forming a three-dimensional object. 15. In a device for directly creating a three-dimensional object designed and created by at least one computer, a computing device that generates an aperture mask image output is connected to a device that generates an aperture mask image output when the image output is at least one of the computer-designed three-dimensional objects. 1
a container defining a thin cross section and containing a reactive fluid; a mold release fluid positioned between the working surface and the bottom of the container; and automatically depositing a thin initial layer of the reactive fluid. a computer-controlled device for forming and positioning an initial layer of the reactive fluid on a work surface; a computer-controlled device for forming a thin cross-section of the reactive fluid corresponding to said image output by exposing the next layer to curing radiation; a computer-controlled device for automatically forming a three-dimensional object by adhering the next layer to the previous layer; and a computer-controlled device for automatically forming the three-dimensional object.