JPH0994883A - Method and apparatus for optically shaping three-dimensional shaped article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shape a shaped article free from a defect while preventing the generation of voids caused by the adhesion of air bubbles in an optical shaping process. SOLUTION: A processed article table 4 is immersed and set in the liquid in the uncured photo-setting resin 2 housed in a processing container 1 and, in this state, a resin cured layer is formed by the irradiation of laser beam through the light pervious window plate 3 of a container and a table is alternately and repeatedly moved by a moving stage 5 to accumulate and form a three- dimensional article 11. In this case, a light pervious window plate 3 for the incidence of laser beam is arranged to the side wall surface of the processing container 1 housing the liquid photo-setting resin and the processed article table 4 is set in the container in a vertical posture so that the surface thereof is turned toward the window plate to perform optical shaping. By this constitution, air bubbles generated on the surface of the table when the processed article table 4 is immersed in the liquid of the photo-setting resin are floated to be degassed to the surface of the liquid and the generation of voids caused by the adhesion of air bubbles is prevented to shape a defect free shaped article.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical molding method in which a photocurable resin is used as a material, and the resin is cured by irradiation of an ultraviolet laser beam on the basis of data on the shape of the molded article to form a three-dimensional molded article. A method and a stereolithography apparatus.

[0002]

2. Description of the Related Art The stereolithography method described above has already been known as a method for processing a three-dimensional shaped object, and various types of stereolithography equipment to which this stereolithography method is applied are disclosed in, for example, "Shape material" issued in 1989. It is introduced in detail in "Modeling Technology by Stereolithography" (Author: Katsumasa Saito) published in Vol 30, No 10, P6-12.

Here, as a laser beam scanner, XY is used.
FIG. 4 shows a stereolithography apparatus that employs a bottom surface irradiation method that employs a plotter, and the conventional stereolithography method of a regulated liquid level method will be described by using this stereolithography apparatus as an example. In FIG. 4, reference numeral 1 denotes a liquid photocurable resin (ultraviolet curable resin) 2 in an uncured state.
And a transparent light-transmitting window plate 3 into which a laser beam described later is incident is provided on the bottom surface of the container 1.
Reference numeral 4 denotes a workpiece table that is immersed in the container 1, and the workpiece table 4 is moved and controlled in the Z-axis direction by a Z-axis moving stage 5. On the other hand, the laser optical system includes an ultraviolet laser light source 6, an X-axis stage of an XY plotter, and a Y-axis.
Mirrors 7a and 7b, and condenser lens 7c on the axis stage
An XY plotter type scanner 7 provided with a shutter 8 and a shutter 8 arranged in an optical path between the scanner 7 and the laser light source 6, and transmits a laser beam from the lower surface side of the container 1 through the transparent window plate 3. Irradiate.

With such a structure, the table 4 is initially immersed in the processing container 1 filled with the photocurable resin 2 from above,
The window plate 3 and the window plate 3 are set in parallel with each other with a gap of about several tens of μm (filled with a liquid photo-curable resin). Here, based on the CAD data 9 in which the cross-sectional data (numerical model) of each layer obtained by cutting the three-dimensional shaped object to be created is stored, the personal computer 10 that is a workstation is used.
The scanner 7 and the shutter 8 are linked and drive-controlled by a command from the laser beam source, and the ultraviolet laser light emitted from the laser light source 6 is directed to the photocurable resin 2 sandwiched between the window plate 3 and the table 4 for raster scanning. While irradiating, the resin cured layer of the first layer having a pattern corresponding to the cross-sectional data of the modeled object is formed on the lower surface of the table 4. The cured resin layer is attached to the lower surface of the table 4. Next, the Z-axis moving stage 5 is raised by one pitch to allow the liquid photo-curable resin to penetrate into the gap between the first resin cured layer and the window plate 3, and then the same operation as described above is performed again. Laser light is irradiated corresponding to the cross-sectional data of the second layer to form a second resin cured layer on the lower surface of the first resin cured layer. Hereinafter, by repeating this operation, the desired three-dimensional shaped objects 11 are deposited and formed on the lower surface of the workpiece table 4 by stacking the cured resin layers. In addition, after removing the optical modeling object 11 from the workpiece table 4, the uncured photo-curable resin adhering to the surface thereof is washed off and completed.

[0005]

The conventional stereolithography method described above has the following problems. 1) As described with reference to FIG. 4, in the system of irradiating the photocurable resin 2 housed in the processing container 1 with the laser beam from the lower surface side, the workpiece table 4 is lowered from above the container 1 and is in a liquid state. When the table 4 is dipped in the liquid photocurable resin 2 in the tank, the air bubbles often adhere to the surface of the table. Moreover, when bubbles adhere to the surface of the table 4, the photo-curable resin 2 does not cure even when the location is irradiated with laser light, which causes defects such as voids in the optically modeled product 11.

2) Further, when the overhanging portion 11a protruding laterally is formed at an intermediate position in the height direction of the molded article 11, the photocurable resin 2 is placed in the container as shown in the figure. If the above-mentioned stereolithography is performed in a state in which the above is fully filled, the following defects occur. That is, the molding portion of the above-mentioned overhang portion is separated from the table 4, and the back of the molding portion is filled with the photocurable resin. For this reason, when the laser light is irradiated from the lower surface side, the laser light passes through the overhang portion and also cures the photocurable resin in the area behind it. As a result, the resin is hardened beyond a predetermined layer thickness, which makes it difficult to process a modeled object having an accurate shape. Particularly, when a fine model of the order of μm is formed by photolithography, the dimensional error becomes large.

3) A method is known in which a mold release agent is applied to the table 4 in advance when removing the modeled article 11 created by the optical molding method from the workpiece table 4, but the mold release agent is applied. It is impossible to easily remove the modeled object from the table by itself, but in reality, a cutter knife or the like is used to forcibly separate it from the table 4.
For this reason, the cutting edge of the cutter knife hits the shaped object 1
There is a possibility that defects such as scratches or deformation may occur in 1.

The present invention has been made in view of the above points, and an object thereof is to solve the problems of 1) to 3) described above, and to perform a stereolithography with high dimensional accuracy without producing defects. A method and a stereolithography apparatus are provided.

[0009]

In order to achieve the above object, the present invention performs stereolithography of a three-dimensional object by using the stereolithography method and stereolithography apparatus as described below. 1) In order to solve the problem of item 1), the workpiece table is held in a vertical posture in the container, and the table is irradiated with laser light from the side to perform stereolithography. The modeling apparatus is provided with a translucent window plate for laser light incidence on the side wall surface of the processing container containing the liquid photocurable resin, and the workpiece table is vertically oriented in the container with the table surface facing the window plate. It is arranged in a posture.

2) In order to solve the problem of item 2), the liquid level of the photocurable resin stored at the bottom of the processing container is set to a level corresponding to the thickness of one cured resin layer. It is assumed that the stereolithography is carried out by holding it, and the stereolithography apparatus has a resin replenishing means for externally supplying a liquid photocurable resin to a processing container having a transparent window plate for laser light incidence on the bottom surface. The liquid level control means including the liquid level measuring means for the photocurable resin stored in the container is provided.

3) In order to solve the problem 3), a metal thin film is formed in advance on the end surface of the non-metal substrate set on the workpiece table, and a three-dimensional object is stereolithographically formed on the metal thin film. The substrate is removed together with the object from the workpiece table, and then the metal thin film is dissolved and removed by an etching method to release the modeled object from the substrate. According to the invention of the above item 1), since the workpiece table is arranged in the vertical position, when the table is inserted into the processing container from above and immersed in the liquid photocurable resin, the table surface is Even if a bubble is generated, the bubble does not adhere to and remains on the table surface and immediately floats and is degassed from the resin liquid surface. Therefore, the bubbles do not affect the stereolithography, and defects such as voids of the modeled object due to the bubbles can be prevented.

On the other hand, in the invention of the above item 2), the photocurable resin stored in the bottom portion of the processing container in accordance with the progress of the stereolithography step always has a liquid level height corresponding to one photocured resin layer. The liquid level is controlled so as to maintain Therefore,
Even if laser light is irradiated from the bottom side when forming the overhanging part of the modeled object, the photo-curable resin will not be excessively hardened beyond the specified layer thickness, and this will enable accurate modeling of the shape. Can form things.

Further, according to the invention of the above item 3), the metal thin film previously deposited on the end face of the substrate (eg, glass substrate) of the workpiece table is melted and removed by the etching method after performing the stereolithography. Thus, when the molded article is released from the substrate, the molded article can be easily removed without using a cutter knife or the like.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below for each item. In the drawings of each embodiment, the same members corresponding to FIG. 4 are denoted by the same reference numerals. [Embodiment 1] FIG. 1 shows an embodiment of an optical modeling apparatus corresponding to claims 1 and 2 of the present invention, which is used for laser light incidence on a processing container 1 filled with a photocurable resin 2. The transparent window plate 3 is provided on the side surface of the container, and the workpiece table 4 is arranged in a vertical (vertical) posture so that the window plate 3 and the table surface face each other. Then, the workpiece table 4 is pitch-fed in the X-axis direction by the moving stage 5 with respect to the Cartesian coordinate axis X-Y-Z shown in the drawing, and the laser beam is used as an optical system based on the cross-sectional data of the model 11. The scanner 7 scans in the Y-axis and Z-axis directions, and the photo-curable resin 2 is laterally irradiated through the transparent window plate 3 to perform stereolithography. As a result, the three-dimensional object 11 is deposited and formed on the vertical table surface of the workpiece table 4.

In this case, when the workpiece table 4 is lowered from above the processing container 1 and immersed in the liquid photocurable resin 2, the bubbles generated on the table surface do not adhere and remain as they are. It floats in the liquid and is deaerated outside the tank. Therefore, it is possible to prevent the occurrence of defects such as voids by avoiding the influence on the stereolithography due to the adhesion of bubbles. [Embodiment 2] FIG. 2 shows an embodiment of an optical molding apparatus corresponding to claims 3 and 4 of the present invention. In this embodiment, the photocurable resin 2 is supplied to the processing container 1 in which a transparent window plate 3 for laser light incidence is fitted on the bottom side.
2 through the supply valve 13 and the supply hose 14 to the bottom of the container, and the photocurable resin 2 supplied to the container 1 through the non-contact type liquid level sensor 15 and the controller 16. The liquid level height H is controlled so as to be a constant level, and in this state, laser light scanning and the workpiece table 4 are performed.
The ascending pitch feed is alternately performed to create the three-dimensional model 11.

Here, the above-mentioned liquid level height H is the molded article 11
Is set in accordance with the thickness L of the resin cured layer for one layer, and the layer thickness is set between the workpiece table 4 or the resin cured layer deposited on the lower surface of the table and the transparent window plate 4. L
In a state where the pitch corresponding to the above is set and the pitch is fed by the moving stage 5, the photo-curable resin 2 is transferred from the tank 12 to the container 2.
When the liquid level reaches a predetermined liquid level height H, the supply valve 13 is closed by the detection signal of the level sensor 15. Then, in this state, laser light is irradiated from the lower surface side of the processing container 1 to cure the resin of the next layer.

According to the above method, when the laser beam is irradiated, the photocurable resin 2 having the liquid level height H corresponding to the thickness of one layer of the modeled article 11 is always provided on the bottom of the processing container 1. Retained, and therefore the overhanging portion 11a
Even when molding is performed, the photo-curable resin 2 is not hardened to an excessive thickness, which enables optical molding with high dimensional accuracy.

[Embodiment 3] FIGS. 3A to 3D show an embodiment of a method corresponding to claim 5 of the present invention.
A glass substrate 17 is detachably set on the side of the lower surface on which the model 11 is molded with respect to the workpiece table 4, and a metal thin film 18 is previously attached to the end surface of the glass substrate 17 by a sputtering method, a vapor deposition method, or the like. It is adhered and formed.

Then, after the modeling object 11 is modeled on the surface of the metal thin film 18 in the stereolithography step shown in FIG. 3A, the workpiece table 4 together with the modeling object 11 is pulled up from the machining container 1 and Then, the glass substrate 17 is removed from the table 4. This detached state is shown in FIG. Next, as shown in FIG. 3C, the glass substrate 17 is turned downward and the metal thin film 1 is placed.
8 is immersed in an etching bath 19 filled with an etching solution 20. Here, the metal thin film 18 is melted and removed by the etching solution 20 as shown in FIG. 3 (d), and the modeling object 11 and the glass substrate 17 are separated. The molded article 11 is taken out after being released from the mold.
It is to be noted that the glass substrate 17 is formed by depositing the metal thin film 18 again, and is then put into the stereolithography process again to be repeatedly used.

[0020]

As described above, the stereolithography method and stereolithography apparatus of the present invention have the following effects. 1) By using the stereolithography apparatus according to claim 2, stereolithography is stereolithographically performed according to the method according to claim 1, whereby bubbles generated when the workpiece table is immersed in the liquid of the photocurable resin are formed on the table surface. It is possible to levitate and separate from the above to deaerate on the liquid surface, thereby avoiding the generation of voids due to the adhesion of air bubbles, and it is possible to perform stereolithography of a high-quality molded object.

2) By using the stereolithography apparatus of claim 4, the stereolithography object is stereolithographically shaped by the method of claim 3 to form an overhang portion at a midpoint of a complicated shape of the molding object. Even in this case, when the laser beam is irradiated, a modeled object with high dimensional accuracy can be stereo-molded without fear of excessive resin curing in the layer thickness direction of the resin cured layer. 3) By adopting the optical modeling method of claim 5, the molded object can be easily and reliably released without using a cutter knife or the like, and scratches on the molded object, which have been a problem in the conventional mold releasing method, Defects such as deformation can be prevented.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an optical modeling apparatus corresponding to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of an optical modeling apparatus corresponding to a second embodiment of the present invention.

3A and 3B are diagrams showing steps of a stereolithography method corresponding to Example 3 of the present invention, in which FIG. 3A is a state diagram in which a molded article is pulled up from a processing container immediately after the end of the stereolithography step, and FIG. State diagram with the glass substrate removed from the work table along with the object,
(C) is a state diagram during a mold release process of a molded article by an etching method, and (d) is a state diagram after mold release

FIG. 4 is a configuration diagram of an entire conventional stereolithography apparatus.

[Explanation of symbols]

 1 Processing Container 2 Liquid Photocurable Resin 3 Transparent Window Plate 4 Workpiece Table 5 Moving Stage 7 Scanner 11 Three-dimensional Model 11a Overhang Part 12 Photocurable Resin Supply Tank 13 Photocurable Resin Supply Valve 15 Liquid Surface level sensor 16 Control part 17 Glass substrate 18 Metal thin film 20 Etching liquid

Claims (5)

[Claims] 1. A method of stereolithography for curing a resin by irradiating an ultraviolet laser beam with a photocurable resin to process a three-dimensional shaped object, which is an uncured liquid photocurable contained in a processing container. The workpiece table is dipped in a flexible resin, and in this state, the resin cured layer is formed by laser light irradiation based on the cross-sectional data of the model, and the workpiece table is moved alternately repeatedly to form a solid shape on the workpiece table. In the one for deposit-molding a three-dimensional object, a three-dimensional object is formed by holding the workpiece table in a vertical position in a container and irradiating the table with laser light from the side. Stereolithography of objects. 2. A stereolithography apparatus used for carrying out the stereolithography method according to claim 1, wherein a side wall surface of a processing container containing a liquid photocurable resin is provided with a transparent window plate for laser light incidence. At the same time, the stereolithography apparatus for a three-dimensional object, characterized in that the workpiece table is arranged in a vertical position in the container with the table surface facing the window plate. 3. An optical molding method, wherein a photo-curable resin is used as a material to cure the resin by irradiation with an ultraviolet laser beam to process a three-dimensional shaped object, which is an uncured liquid photo-curing housed in a processing container. Immerse the workpiece table in the resin, and based on the cross-section data of the model, form the resin cured layer by laser light irradiation from the bottom side of the container and move the workpiece table alternately and repeatedly to create the workpiece table. In the case of stacking and molding a three-dimensional shaped object, optical molding is performed by maintaining the liquid level of the photo-curable resin stored at the bottom of the container at a level corresponding to the thickness of one cured resin layer. A method for stereolithography of a three-dimensional object, comprising: 4. A stereolithography apparatus used for carrying out the stereolithography method according to claim 3, wherein a liquid photocurable liquid is externally applied to a processing container having a transparent window plate for laser light incidence on the bottom surface. An optical modeling apparatus for a three-dimensional object, comprising: a resin replenishing means for supplying a resin; and a liquid level control means including a liquid level measuring means for the photocurable resin stored in a container. 5. An optical molding method for curing a resin by irradiating an ultraviolet laser beam with a photo-curing resin as a material to process a three-dimensional shaped object, which is an uncured liquid photo-curing accommodated in a processing container. Immerse the workpiece table in the resin, and based on the cross-section data of the model, form the resin cured layer by laser light irradiation from the bottom side of the container and move the workpiece table alternately and repeatedly to create the workpiece table. In one in which a three-dimensional shaped object is deposited and formed, a metal thin film is formed in advance on the end surface of the non-metal substrate set on the workpiece table, and the three-dimensional object is optically shaped on the metal thin film and then the shaped object is formed. The substrate is removed from the workpiece table together, and then the metal thin film is dissolved and removed by an etching method to release the model from the substrate. Method.