JP2002067173A - Optically molding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To continuously manufacture an optically molded model being excellent in both of strength and appearance by eliminating air bubbles mixed in a photo-curing resin by using a simple device constitution. SOLUTION: This optically molding device is equipped with a resin tank 1, a molding table 4, a moving means 5, and an irradiation means. In this case, the resin tank 1 stores the liquid-form photo-curing resin 2. The molding table 4 is arranged in the resin tank in such a manner that at least the upper surface may become horizontal. The moving means 5 vertically moves the molding table 4 in the vertical direction. The irradiation means irradiates a laser beam to the liquid surface 24 of the photo-curing resin 2 based on the cross section data of an article. In such an optically molding device, pressure-reducing means 6 and 7, which always or intermittently reduce the pressure of a space above the liquid surface 24 of the photo-curing resin 2, are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical molding apparatus for creating an article having a desired shape from a photocurable resin by utilizing a photocuring phenomenon.

[0002]

2. Description of the Related Art Conventionally, regarding an optical shaping apparatus, a "laminate manufacturing system" published by the Industrial Research Institute, Inc. (November, 1996)
On page 19, section 2.1 of the first edition of the first edition on March 15, the principle of stereolithography is described. This content will be described with reference to FIGS. FIG. 11 is a perspective view of a product model defined by three-dimensional CAD, FIG. 12 is a perspective view of a cross-sectional data group of the product model, and FIGS. 13 to 15 show a process of manufacturing a stereolithography model based on the cross-sectional data group. FIG.

In FIG. 11, a product model 21 defined by three-dimensional CAD is composed of a large-diameter cylindrical portion 21a and a small-diameter cylindrical portion 21b formed thereon. The product model 21, as shown in FIG. 12, a sectional data group 22 are sequentially sliced at intervals d ₁ in the vertical direction in FIG. Section data group 22 is a collection of section data from the section data P ₁ at the bottom to the section data P _n at the top of the product model 21.

[0004] Figure 13 is a representation of the step of shaping the bottom of the section data P ₁ form, liquid light curing resin 1
L-shaped molding table 104 is immersed in resin tank 101 in which storage tank 02 is stored, and upper surface 104b of horizontal portion 104a is formed.
Are located at a depth of an interval d ₁ (see FIG. 12) obtained by slicing the product model 21 (see FIG. 11) with reference to the liquid level 124. In this state, the liquid photocurable resin 1
02 to cure the liquid level 12 from above the liquid level 124.
The laser light is irradiated from the laser light irradiation device 125 toward 4. At this time, the laser light irradiation device 125 is adjusted so that the laser light is focused on the liquid surface 124, and is based on the cross-sectional data P ₁ (see FIG. 12) in the X direction (FIG. 13).
Are scanned in the horizontal direction (the horizontal direction of FIG. 13) and the horizontal Y direction (the direction perpendicular to the paper surface in FIG. 13) perpendicular to the horizontal direction. In this case, it is also possible to laser beam irradiation apparatus 125 is mechanically controlled so as to scan only the scope of the section data P _1, scanned in a somewhat wider range than the section data P _1, section only the laser beam irradiation apparatus 125 is ON range of data _{P 1}
It is also possible to electrically control such that As a result, photocurable resin 102 liquid cures over the thickness and equal to the distance d ₁ in the range equal to the cross-section data P _1, a cured product M _1.

[0005] Next, as shown in FIG.
4 of the horizontal portion 104a, inside and further sedimentation of only the light-curing resin 102 distance _{d 1} from the state of FIG. 13, the laser beam irradiation device on the basis of the section data _{P 2} (see FIG. 12) 125
Is scanned in the X and Y directions. Thus, the photocurable resin 102 in liquid form, and distance d in the range equal to the cross-section data P ₂
Over ₁ equal thickness and cured on the cured product M _1, a cured product M _2. In this case, curing the top of the cured product _{M 1} product _{M 2}
Are firmly bonded to each other to form an integrated cured product M.

By repeating such an operation up to the top section data P _n (see FIG. 12) of the section data group 22, as shown in FIG.
An optical modeling model 23 having the same shape as the product model 21 (see FIG. 11) is formed inside. After molding is completed, molding table 1
04 is raised and moved to the outside of the photocurable resin 102, and the stereolithography model 23 is removed.

[0007]

However, the above prior art has the following problems. FIG. 16 and FIG.
7, the problem of the prior art will be described. As shown in FIG. 16, after the molding operation of the optical molding model 23 (see FIG. 15) is completed, the molding table 104 is lifted out of the photocurable resin 102 (in the figure, the state of the broken line), and the optical molding is performed. Model 23
After removing the, again for the next molding work, allowed to settle forming table 104 from the liquid surface 124 by a distance d ₁ (in the figure,
(Solid line state), and repeat the stereolithography process. At this time,
That is, when the horizontal portion 104 a of the molding table 104 moves in and out of the liquid surface 124, bubbles 3 of various sizes are mixed into the photocurable resin 102. The liquid level 12 of the mixed bubbles 3
4, a very small portion of the molding table 104 cannot be easily raised because the photocurable resin 102 has a very high viscosity.
The bubbles 3 exist everywhere inside the photo-curable resin 102 regardless of above and below a.

When the above-described stereolithography process is performed in such a state, the following problems occur.
That is, as shown in FIG. 17, a stereolithography model 23 molded using the photocurable resin 102 mixed with the air bubbles 3 has a cavity 25 therein and a concave portion 26 on the outer peripheral surface.
Is present, which causes a problem that the overall strength is reduced and the appearance is lost. Further, at the moment when the bubble 3 is ruptured, a portion irradiated with the laser beam becomes a void 27. Such a void 27 is generated everywhere. In particular, when the void 27 is generated on an outer peripheral portion, the layers are separated. The main factor that causes it.
That is, the actual stereolithography process is performed by the photocurable resin 102.
This cannot be achieved without eliminating bubbles 3 that have entered inside.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention according to claims 1, 2 and 3 is to provide a simple apparatus configuration for removing air bubbles mixed in a photocurable resin. An object of the present invention is to provide a stereolithography apparatus capable of continuously manufacturing a stereolithography model excellent in both strength and appearance by eliminating the use thereof.

[0010]

In order to solve the above-mentioned problems, the invention according to claim 1 is directed to a resin tank for storing a liquid photocurable resin and a resin tank in which at least the upper surface is horizontal. An optical shaping apparatus comprising: a molding table arranged in a vertical direction; moving means for vertically moving the molding table; and irradiation means for irradiating the liquid surface of the photocurable resin with a laser beam based on cross-sectional data of the article. And a pressure reducing means for constantly or intermittently reducing the pressure in the space above the liquid level of the photocurable resin.

According to a second aspect of the present invention, there is provided a resin tank for storing a liquid photocurable resin, a molding table arranged in the resin tank so that at least the upper surface is horizontal, and And a irradiating means for irradiating the liquid surface of the photocurable resin with a laser beam based on the cross-sectional data of the article. A passage, a circulating means for circulating the photocurable resin over the circulation conduit and the resin tank, and a decompression chamber disposed in the circulation conduit,
A pressure reducing means for constantly or intermittently reducing the pressure in the space above the liquid level of the photocurable resin in the decompression chamber.

According to a third aspect of the present invention, there is provided a resin tank for storing a liquid photocurable resin, a molding table arranged in the resin tank so that at least an upper surface thereof is horizontal, and A light-curing resin stored in the resin tank, wherein the light-curing resin has a moving means for moving up and down, and an irradiation means for irradiating the liquid surface of the photocurable resin with a laser beam based on cross-sectional data of the article. Sweep means moving along the liquid surface, a drive means for moving the sweep means, and a control means for driving the drive means in accordance with pre-programmed logical processing information.

The stereolithography apparatus according to the first aspect of the present invention is provided with a decompression means for constantly or intermittently reducing the pressure in the space above the liquid surface of the photocurable resin. The pressure in the upper space above the liquid level is constantly or intermittently reduced to suck and remove air bubbles mixed into the photocurable resin.

According to a second aspect of the present invention, there is provided an optical molding apparatus, wherein: a circulating pipe provided in communication with the resin tank; circulating means for circulating the photocurable resin between the circulating pipe and the resin tank; By providing a decompression chamber disposed in the road and a decompression means for constantly or intermittently depressurizing the pressure of the upper space above the liquid level of the photocurable resin in the decompression chamber, the circulation means is driven, The photocurable resin is circulated between the tank and the resin conduit, and the pressure in the upper space above the liquid surface of the photocurable resin is constantly or intermittently reduced by the decompression means in the decompression chamber provided in the circulation conduit. Then, air bubbles mixed into the photocurable resin are sucked and removed.

According to a third aspect of the present invention, there is provided an optical shaping apparatus, wherein: a sweeping means for moving along a liquid surface of a photocurable resin stored in a resin tank; a driving means for moving the sweeping means; Control means for driving the means in accordance with pre-programmed logical processing information,
In accordance with logical processing information such as a pre-programmed sweep timing and a sweep range, the sweep means is moved by the drive means along the liquid surface of the photocurable resin, and without interrupting the optical shaping process, the Bubbles remaining on the liquid surface are forcibly collected.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described. Note that the basic configuration of the stereolithography apparatus, the principle of the stereolithography method, and the product model are the same as those in the related art, and thus detailed description thereof is omitted. Note that the product model 21 and the cross-sectional data group 22 already shown in FIGS. 11 and 12 are merely examples, and the present invention is not limited thereto, and the embodiments of the present invention can be applied to various articles.

(Embodiment 1) FIGS. 1 to 4 show Embodiment 1, FIG. 1 is a longitudinal sectional view of an optical molding apparatus in which air bubbles are mixed, and FIG. 2 is an optical molding apparatus in a state where an airtight chamber is depressurized. FIG. 3 is a longitudinal sectional view of the optical shaping apparatus after bubbles have disappeared, and FIG. 4 is a longitudinal sectional view of the optical shaping apparatus showing a modification of the molding table.

In FIG. 1, a liquid photocurable resin 2 is stored in a resin tank 1, and an L-shaped molding table 4 is stored.
Is vertically movably supported by an elevator 5 as moving means provided outside the resin tank 1 so that the horizontal portion 4a can be immersed in the photocurable resin 2.
Above the resin tank 1, as in the prior art, the cross-sectional data P ₁ to P ₁ of the product model 21 (see FIG. 11) as an article is provided.
Based on P _n (see FIG. 12), a laser light irradiation device (not shown) is provided as irradiation means for irradiating the laser light while scanning in the XY directions (see FIG. 13). The resin tank 1, the molding table 4, and the elevator 5 are entirely surrounded by an airtight chamber 7.
It is connected to the. The vacuum pump 6 and the hermetic chamber 7 constitute a pressure reducing means. A laser light transmitting window 8 is provided on the upper surface of the airtight chamber 7 so that a laser beam can be applied to the liquid surface 24 of the photocurable resin 2. The laser light transmitting window 8 can be opened and closed by a shutter 9. Has become. A seal 10 is provided around the laser light transmitting window 8 to ensure airtightness in the airtight chamber 7 when the shutter 9 is closed.

Next, an optical shaping method using the optical shaping apparatus having the above configuration will be described. As shown in FIG. 1, an upper surface 4b of a horizontal portion 4a of a molding table 4 is placed in a resin tank 1 in which a photo-curable resin 2 is stored.
1 (see FIG. 11) is sunk so as to be located at a depth of the interval d ₁ (see FIG. 12) obtained by slicing. At this time, as described in the related art, the bubbles 3 are mixed in the photocurable resin 2. In this state, prior to the irradiation of the laser beam, after the shutter 9 is closed, the inside of the airtight chamber 7 is depressurized by the vacuum pump 6. When the pressure in the airtight chamber 7, that is, in the space above the liquid surface 24 of the photocurable resin 2 is reduced, the bubbles 3 mixed into the photocurable resin 2 gradually become photocured as shown in FIG. Rises to the vicinity of the liquid surface 24 of the conductive resin 2 and bursts and disappears. As a result, as shown in FIG. 3, the inside of the photocurable resin 2 is improved to a state in which no bubbles 3 exist.

In the present embodiment, the lower surface 4c of the horizontal portion 4a of the molding table 4 does not need to be a horizontal surface, but rather, as shown in FIG. The air bubbles 3 are actively removed along the slope.
4 can be raised. In addition, the lower surface 4c exhibits the same operation even when a convex spherical surface is used.

After the bubbles 3 disappear, the shutter 9 is opened,
Cross-sectional data P ₁ from a laser beam irradiation device (not shown)
2), the laser beam passes through the laser beam transmitting window 8 and reaches the liquid surface 24 of the photo-curable resin 2 to obtain a cured product. Thereafter, similarly to the conventional technique, by repeating the lowering of the molding table 4 and the irradiation of the laser beam, it is possible to obtain a stereolithography model in which the cavity 25, the concave portion 26, and the void 27 (see FIG. 17) do not exist.

As for the pressure reduction inside the hermetic chamber 7, the vacuum pump 6 may be operated continuously for a certain period of time. However, as the recommended pressure reduction conditions in the present embodiment, the following intermittent pressure reduction conditions are desirable. . (1) The internal pressure of the hermetic chamber 7 is reduced to about 0.66 kPa or less. (2) After the pressure is reduced to 0.66 kPa or less, the inside of the hermetic chamber 7 is instantaneously leaked and raised to around 2.0 kPa. (3) Repeat (1) and (2) for 5 minutes or more.

In the case of continuous depressurization, a phenomenon in which the rising bubbles 3 cover the liquid surface 24 and eventually overflow from the resin tank 1 is seen. However, such a phenomenon is avoided by intermittent decompression. . Of course, the present embodiment is not limited to the above-mentioned specific intermittent depressurizing conditions, but may employ other suitable configurations and operating conditions that produce the above-described effects.

According to the present embodiment, air bubbles mixed in the photocurable resin are reliably removed by using a simple apparatus configuration, and there are no cavities, recesses, and voids, and the strength and appearance are excellent. Stereolithography models can be manufactured continuously.

In this embodiment, the laser light transmitting window 8 is covered by the shutter 9 which can be opened and closed. Alternatively, the laser light transmitting window 8 is closed by a light transmitting member, and the airtight chamber 7 is closed. The structure may be such that airtightness is maintained. In this case, since the focal position of the laser beam is shifted, the correction is necessary. However, it is not necessary to break the vacuum inside the hermetic chamber 7, and the degree of vacuum can be kept almost constant. Can be done

Next, a modified example of the molding table of the present embodiment will be described. This modification is based on the empirical fact that in the stereolithography process, the air bubbles 3 below the horizontal portion 4a of the molding table 4 do not substantially affect the formation of a good stereolithography model, As shown in FIG.
The lower surface 4c of the horizontal portion 4a is a concave spherical surface. As a result, the bubble 3 below the horizontal portion 4a rises and is captured by the concave portion on the lower surface 4c. According to the present modification, since only the air bubbles 3 existing above the horizontal portion 4a need to be removed, the pressure reduction condition can be relaxed. The phenomenon overflowing from 1 can be avoided. Also in this modification, the shape of the lower surface 4c of the horizontal portion 4a of the molding table 4 is not limited to a concave spherical surface, but may be changed to another shape that can capture the bubbles 3 below the horizontal portion 4a of the molding table 4. Can be.

(Embodiment 2) FIG. 5 shows Embodiment 2 and is a longitudinal sectional view of an optical shaping apparatus. The stereolithography apparatus of the present embodiment is obtained by removing an airtight chamber and the like from the stereolithography apparatus of the first embodiment, and adding a circulation pipe and the like to a resin tank.

In FIG. 5, a liquid photocurable resin 2 is stored in a resin tank 1, and an L-shaped molding table 4 can immerse its horizontal portion 4 a in the photocurable resin 2. As described above, the resin tank 1 is vertically movably supported by the elevator 5 as a moving means provided outside the resin tank 1. Above the resin tank 1, cross-sectional data P _{1 to} P _n of a product model 21 (see FIG. 11) as an article are provided in the same manner as in the related art.
(See FIG. 12), the laser beam is directed in the XY directions (FIG. 1).
3) is provided with a laser beam irradiation device (not shown) as irradiation means for irradiating while scanning. In the resin tank 1 in which the photocurable resin 2 is stored, a circulation pipe 11 is provided in communication with the resin tank 1 so that an upper portion thereof serves as an intake port and a lower portion thereof serves as a discharge port. The photo-curable resin 2 is configured to circulate through the resin tank 1 and the resin pipeline 11 by the pump 12 serving as a circulating means. A decompression chamber 13 is provided in the middle of the circulation line 11, and the upper part thereof is connected to a vacuum pump 14. The decompression chamber 13 and the vacuum pump 14 constitute decompression means. The circulation line 11 and the decompression chamber 13 connect the pipe 11a from the intake to the upper part of the decompression chamber 13 and the pipe 11b to the discharge port to the lower part of the decompression chamber 13.

Next, an optical shaping method using the optical shaping apparatus having the above configuration will be described. As shown in FIG. 5, the upper surface 4 b of the horizontal portion 4 a of the molding table 4 is placed in the resin tank 1 in which the photocurable resin 2 is stored.
1 (see FIG. 11) is sunk so as to be located at a depth of the interval d ₁ (see FIG. 12) obtained by slicing. At this time, as described in the related art, the bubbles 3 are mixed in the photocurable resin 2. In this state, prior to the laser beam irradiation, first, the pump 12 is operated to reflux the photocurable resin 2, and at the same time, the vacuum pump 14 is operated to activate the liquid level of the photocurable resin 2 inside the decompression chamber 13. The pressure in the upper space of 24A is reduced. The bubbles 3 mixed in the photocurable resin 2 sent into the decompression chamber 13 are removed by the same operation as in the first embodiment. Thereafter, the photocurable resin 2 from which the bubbles 3 have been removed is returned to the lower part of the resin tank 1 by the circulation pipe 11 leading to the discharge port connected to the lower part of the decompression chamber 13. By repeating the above operations, the bubbles 3 inside the photocurable resin 2 gradually disappear and finally disappear.

As a result of studying the recommended decompression conditions that cause the above-mentioned effects, it was preferable in the configuration of the present embodiment to operate the vacuum pump 14 continuously. After the bubbles have disappeared, a laser beam based on the cross-sectional data P ₁ (see FIG. 12) is irradiated from a laser beam irradiation device (not shown),
The laser beam reaches the liquid surface 24 of the photo-curable resin 2 to obtain a cured product. Thereafter, similarly to the prior art, the cavity 25 and the concave portion 2 are formed by repeating the lowering of the molding table 4 and the irradiation of the laser beam.
It is possible to obtain a stereolithography model having no voids 6 and voids 27 (see FIG. 17).

According to the present embodiment, air bubbles mixed in the photocurable resin are reliably removed by using a simple apparatus configuration, and there are no cavities, recesses and voids, and the strength and appearance are excellent. Stereolithography models can be manufactured continuously. In addition, since air bubbles are removed in the decompression chamber connected to the resin tank, there is no need to seal the resin tank, and continuous decompression inside the decompression chamber is possible. Therefore, there is no need to stop the stereolithography process, and the bubbles can be removed quickly, so that the stereolithography operation can be efficiently promoted.

(Embodiment 3) FIG. 6 shows Embodiment 3 and is a longitudinal sectional view of an optical shaping apparatus. The configuration of the optical shaping apparatus of the present embodiment is a combination of the configuration of the first embodiment and the configuration of the second embodiment. More specifically, as shown in FIG. 6, a portion including the resin tank 1, the molding table 4, and the elevator 5 in the second embodiment is sealed in the airtight chamber 7 in the first embodiment. Therefore, each component is denoted by the same reference numeral as the corresponding component in the first and second embodiments, and the description is omitted.

Next, an optical shaping method using the optical shaping apparatus having the above configuration will be described. The function of each component is substantially the same as in the first and second embodiments. The vacuum pump 6 as the first pressure reducing means and the vacuum pump 14 as the second pressure reducing means can be operated at the same time, or can be operated at the same time. Reflux of photocurable resin 2 containing bubbles by pump 12 and vacuum pump 1
Since air bubbles are effectively removed by depressurizing the upper space of the decompression chamber 13 by the vacuum pump 4, the airtight chamber 7 by the vacuum pump 6 is removed.
The decompression inside may be such that the removal of air bubbles in contact with the liquid surface 24 is promoted, and the decompression condition may not be as severe as in the first embodiment.

According to the present embodiment, in addition to the same effect as in the second embodiment, there is no need to stop the stereolithography process, and the removal of air bubbles is performed more quickly. Can be promoted.

(Embodiment 4) FIGS. 7 to 9 show Embodiment 4, FIG. 7 is a longitudinal sectional view of the optical shaping apparatus, FIG. 8 is a perspective view of the upper part of the optical shaping apparatus, and FIG. It is a perspective view which shows the modification of. The configuration of the optical shaping apparatus of the present embodiment is basically the same as that of the optical shaping apparatus of Embodiment 1 except that an airtight chamber, a vacuum pump, a laser light transmission window, a shutter and a seal are omitted, and a sweeping means is added to this. It was done.

In FIG. 7, a liquid photocurable resin 2 is stored in a resin tank 1, and an L-shaped molding table 4 can immerse its horizontal portion 4 a in the photocurable resin 2. As described above, the resin tank 1 is vertically movably supported by the elevator 5 as a moving means provided outside the resin tank 1. Above the resin tank 1, cross-sectional data P _{1 to} P _n of a product model 21 (see FIG. 11) as an article are provided in the same manner as in the related art.
(See FIG. 12), the laser beam is directed in the XY directions (FIG. 1).
3) is provided with a laser beam irradiation device (not shown) as irradiation means for irradiating while scanning. As shown in FIG. 8, two guide rails 15 laid horizontally in the horizontal direction are arranged opposite to each other on the upper side of the long side of the resin tank 1. Each guide rail 15 is a resin tank 1
Two Zs as drive means fixed to the long side outer surface
It is movably supported in the Z direction (vertical direction) by the directional air cylinder 16, and the upper surface of the guide rail 15 is adjusted so that the height of the photocurable resin 2 from the liquid surface 24 is uniform. . On the upper surface of the two guide rails 15,
A bar-shaped sweeping member 17 is provided in the short side direction of the resin tank 1. The sweeping member 17 fixes a continuum 18 having a large number of needle-like projections over the short side direction of the resin tank 1 such that the tips of the needle-like projections face the liquid surface 24,
It is connected to an X-direction air cylinder 19 as a driving means fixed to the guide rail 15, and is connected to the X-direction (guide rail 1).
5 (horizontal direction). The guide rail 15, the sweeping member 17, and the continuum 18 constitute a sweeping means.

In this embodiment, an air cylinder is used as the driving means in the X and Z directions of the sweeping means. However, the present invention is not limited to this, and a rotary driving member such as a hydraulic cylinder or an electric motor and a rack are used. A mechanism combining an and pinion, a timing belt, a cam, and the like can also be used. Z direction cylinder 16, X direction cylinder 19
Are connected to a control means 20 such as an NC control device or a computer to which pre-programmed logical processing information (Z-direction height of the sweeping means, X-direction scanning sequence, scanning range, etc.) is input.

Next, a description will be given of an optical shaping method using the optical shaping apparatus having the above configuration. As shown in FIG. 7, in the resin tank 1 storing the photo-curable resin 2, the upper surface 4b of the horizontal portion 4a of the molding table 4 slices the product model 21 (see FIG. 11) with the liquid surface 24 as a reference. Distance d ₁ (FIG. 12
(See below). At this time,
As described in the prior art, air bubbles 3
Is mixed. In this state, prior to the irradiation of the laser beam, as shown in FIG. 8, by driving the Z-direction cylinder 16 based on the information input to the control means 20 in advance, the sweep member 17 Is performed in the Z direction. In the present embodiment, the sweep member 1
The tip of the continuum 18 having needle-like projections fixed to 7 is
Although it is positioned so as to be immersed about 0.1 to 0.5 mm from the liquid surface 24 of the photocurable resin 2, the position of the tip of the continuous body 18 in the Z direction is not limited to this.
The liquid surface 24 of the photocurable resin 2 may be made to coincide with the liquid surface 24 or may be located slightly above the liquid surface 24.

Next, by driving the X-direction cylinder 19 based on the information previously input to the control means 20, the sweeping member 17 is moved to the position e in the X-direction as shown in FIG.
To the position f. With this movement, the bubbles 3 existing near the liquid surface 24 of the photocurable resin 2 become continuous bodies 1
8 between the closely aligned needle-like projections and reach a position f substantially not involved in the stereolithography process. After the bubble 3 reaches the position f, a laser beam based on the cross-sectional data P ₁ (see FIG. 12) is irradiated from a laser beam irradiation device (not shown), and the laser beam reaches the liquid surface 24 of the photocurable resin 2. , To obtain a cured product. Hereinafter, similarly to the conventional technique, the cavity 25,
It is possible to obtain a stereolithography model in which the concave portion 26 and the void 27 do not exist.

According to the present embodiment, air bubbles mixed into the photocurable resin are reliably recovered by using a simple apparatus configuration, and have no strength, appearance and no cavities, recesses and voids. Stereolithography models can be manufactured continuously. Further, since the air bubbles can be collected only by the mechanical operation of the sweeping means, the stereolithography process can be automated.

Next, a modification of the sweeping means of this embodiment will be described. In FIG. 9, instead of the continuum 18 having needle-like projections of the present embodiment, a reticulated continuum 28 is fixed to the sweeping member 17, and the tip thereof is opposed to the liquid surface 24. Even with this configuration, the liquid surface 24 of the photocurable resin 2
Is trapped by the densely woven mesh at the tip of the mesh-like continuum 28, and can be transferred to a position f (see FIG. 7) that is not substantially involved in the stereolithography process.

(Embodiment 5) FIG. 10 shows Embodiment 5 and is a longitudinal sectional view of an optical shaping apparatus. Since the stereolithography apparatus of the present embodiment is obtained by adding a sub-tank and a circulation pipe to the stereolithography apparatus of the fourth embodiment, only the added portions will be described, and the same members will be denoted by the same reference numerals. The illustration and the description are omitted.

In FIG. 10, a sub-tank 29 is provided on the upper side of the resin tank 1 (the side opposite to the side on which the elevator 5 is disposed).
And the sub-tank 29 are partitioned by a shutter 30 that moves up and down. A circulation line 31 is provided from the sub tank 29 to the lower portion of the resin tank 1, and a circulation line 3 is provided.
In FIG. 1, a pump 32 is provided as circulation means for refluxing the photocurable resin 2. The shutter 30 and the pump 32 are connected to the control device 20 described in the fourth embodiment.
It is connected to the. Other configurations are the same as those of the fourth embodiment.

Next, an optical shaping method using the optical shaping apparatus having the above configuration will be described. In the present embodiment,
The operation is the same as that of the fourth embodiment until the bubbles 3 existing near the liquid surface 24 of the photocurable resin 2 are collected at the position f by the action of the sweeping means. Subsequently, based on the information input in advance to the control means 20, at the timing when the sweep member 17 reaches the position f, the shutter 30 is opened,
The pump 32 is driven, and the photocurable resin 2 into which the bubbles 3 are mixed flows down to the sub tank 29. The photocurable resin 2 that has flowed into the sub-tank 29 is returned to the resin tank 1 via the circulation pipe 31 again. Thus, the bubbles 3 are collected from above the horizontal portion 4a of the molding table 4. After the bubbles 3 are collected, a laser beam is irradiated from a laser beam emitting device (not shown) based on the cross-sectional data P ₁ (see FIG. 12), and the laser beam reaches the liquid surface 24 of the photocurable resin 2 and is cured. Get things. Thereafter, similarly to the related art, by repeating the lowering of the molding table 4 and the irradiation of the laser beam, it is possible to obtain an optical modeling model in which the cavity 25, the concave portion 26, and the void 27 do not exist.

According to this embodiment, the mechanical operation of the sweeping means and the sub-tank and the circulation pipe make it possible to reliably collect the air bubbles mixed in the photocurable resin. Does not exist, and a stereolithography model excellent in both strength and appearance can be obtained with high reliability.

In this embodiment, the reticulated continuum 28 shown in FIG. 9 can be applied. Further, in the present embodiment, the sub tank 29 may have the same configuration and operation as the decompression chamber 13 (see FIG. 5) in the second embodiment. In this case, not only the collection but also the removal of the bubbles 3 are performed. It is possible.

The technical idea of the following configuration is derived from the above specific embodiment. (Supplementary note) (1) A resin tank for storing a liquid photocurable resin,
A molding table arranged in the resin tank so that at least the upper surface is horizontal, a moving unit for vertically moving the molding table, and a liquid of the photo-curable resin which emits a laser beam based on cross-sectional data of the article. An optical molding apparatus having an irradiation unit for irradiating a surface, an airtight chamber containing the resin tank, the molding table, and the moving unit, and a first air pressure that constantly or intermittently reduces the pressure in the airtight chamber. A pressure reducing unit, a circulation line arranged in communication with the resin tank, a circulation unit for circulating the photocurable resin over the circulation line and the resin tank, and a circulation line arranged in the circulation line. Decompression chamber,
A stereolithography apparatus comprising: a second decompression unit that constantly or intermittently decompresses the pressure in a space above the liquid level of the photocurable resin in the decompression chamber.

According to the supplementary note (1), air bubbles mixed in the photocurable resin can be reliably removed by using a simple device configuration.
There are no cavities, recesses, and voids, and a stereolithography model excellent in strength and appearance can be continuously manufactured.
In addition, since it is not necessary to stop the stereolithography process and the bubbles can be removed more quickly, the stereolithography operation can be promoted more efficiently.

(2) A resin tank for storing a liquid photocurable resin, a molding table arranged in the resin tank so that at least the upper surface is horizontal, and moving means for vertically moving the molding table. And an irradiation means for irradiating the liquid surface of the photo-curable resin with a laser beam based on the cross-sectional data of the article, along the liquid surface of the photo-curable resin stored in the resin tank. A driving means for moving the sweeping means, a sub-tank disposed in communication with an upper portion of the resin tank, an openable / closable shutter provided between the resin tank and the sub-tank, A circulation line connecting the lower part of the resin tank and the sub-tank, a circulation means for circulating the photocurable resin over the sub-tank, the circulation line and the resin tank, Control means for driving the step, the shutter and the circulation means in accordance with preprogrammed logical processing information.

According to the supplementary note (2), the mechanical operation of the sweeping means and the sub-tank and the circulating conduit ensure that the air bubbles mixed in the photocurable resin can be recovered.
There is no cavity, recess, or void, and a stereolithography model excellent in strength and appearance can be obtained with high reliability.

(3) The optical shaping apparatus according to (2), wherein at least a part of the sweeping means is constituted by a needle-like or net-like continuous body.

According to the supplementary note (3), in addition to the effect of the supplementary note (2), the bubbles existing in the vicinity of the liquid surface of the photocurable resin are replaced with the needle-like projections at the tip of the continuous body. Alternatively, it can be captured by a densely woven mesh and transported to a location that is not substantially involved in the stereolithography process.

[0053]

According to the first aspect of the present invention, the pressure in the upper space of the liquid surface is constantly or intermittently reduced by the pressure reducing means so as to suck and remove air bubbles mixed in the photocurable resin. As a result, air bubbles mixed into the photocurable resin are reliably removed using a simple device configuration, and there are no cavities, recesses, and voids, and a stereolithography model with excellent strength and appearance is continuously obtained. Can be manufactured.

According to the second aspect of the present invention, the circulating means is driven to circulate the photocurable resin between the resin tank and the resin pipe, and the pressure reducing means is provided in the decompression chamber provided in the circulating pipe. The pressure in the space above the liquid surface is constantly or intermittently reduced to suck and remove air bubbles mixed in the photo-curable resin. By using the apparatus configuration, the solid model is reliably removed, and a stereolithography model excellent in strength and appearance without any cavities, recesses, and voids can be continuously manufactured. In addition, since it is not necessary to stop the stereolithography process and the bubbles can be quickly removed, the stereolithography operation can be efficiently promoted.

According to the third aspect of the present invention, the sweeping means is moved by the driving means along the liquid surface of the photocurable resin in accordance with logical processing information such as a sweep timing and a sweep range which are programmed in advance. Bubbles remaining on the liquid surface of the photocurable resin are forcibly collected without interrupting the molding process, so bubbles mixed in the photocurable resin can be reliably removed using a simple device configuration. Recovered, hollow,
Since there are no concave portions and no voids, a stereolithography model excellent in both strength and appearance can be continuously manufactured. Also,
Since the bubbles can be collected only by the mechanical operation of the sweeping means, the stereolithography process can be automated.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an optical shaping apparatus according to a first embodiment in which bubbles are mixed.

FIG. 2 is a longitudinal sectional view of the optical shaping apparatus in a state where a pressure in an airtight chamber of the first embodiment is reduced.

FIG. 3 is a vertical cross-sectional view of the optical shaping apparatus according to the first embodiment after bubbles have disappeared.

FIG. 4 is a longitudinal sectional view of an optical shaping apparatus showing a modification of the molding table according to the first embodiment.

FIG. 5 is a longitudinal sectional view of the optical shaping apparatus according to the second embodiment.

FIG. 6 is a longitudinal sectional view of an optical shaping apparatus according to a third embodiment.

FIG. 7 is a longitudinal sectional view of an optical shaping apparatus according to a fourth embodiment.

FIG. 8 is a perspective view of an upper portion of the optical shaping apparatus according to the fourth embodiment.

FIG. 9 is a perspective view showing a modification of the sweeping means of the fourth embodiment.

FIG. 10 is a longitudinal sectional view of an optical shaping apparatus according to a fifth embodiment.

FIG. 11 shows a three-dimensional C subject to the prior art and the present invention.
It is a perspective view of the product model defined by AD.

FIG. 12 is a perspective view of a cross-sectional data group of a product model to which the related art and the present invention are applied.

FIG. 13 is an explanatory diagram of a process of manufacturing a stereolithography model based on a cross-sectional data group according to a conventional technique.

FIG. 14 is an explanatory diagram of a process of manufacturing a stereolithography model based on a cross-sectional data group according to a conventional technique.

FIG. 15 is an explanatory diagram of a process of manufacturing a stereolithography model based on a cross-sectional data group according to a conventional technique.

FIG. 16 is an explanatory diagram showing a defect during the stereolithography process of the related art.

FIG. 17 is an explanatory view showing a defect after a stereolithography process according to the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Resin tank 2 Photocurable resin 4 Molding stand 5 Elevator 6 Vacuum pump 7 Airtight room 24 Liquid level

Claims (3)

[Claims] 1. A resin tank for storing a liquid photocurable resin, a molding table disposed in the resin tank so that at least the upper surface is horizontal, and a moving means for vertically moving the molding table. Irradiating means for irradiating the liquid level of the photocurable resin with a laser beam based on the cross-sectional data of the article, wherein the pressure in the upper space of the liquid level of the photocurable resin is constantly or intermittently controlled. An optical shaping apparatus comprising: a pressure reducing means for reducing pressure. 2. A resin tank for storing a liquid photo-curable resin, a molding table arranged in the resin tank so that at least the upper surface is horizontal, and moving means for vertically moving the molding table. A laser beam irradiating means for irradiating the liquid surface of the photocurable resin with a laser beam based on the cross-sectional data of the article; a circulation line disposed in communication with the resin tank; A circulating means for circulating the photocurable resin over the passage and the resin tank; a decompression chamber provided in the circulation pipe; and a pressure in a space above the liquid level of the photocurable resin in the decompression chamber. And a pressure reducing means for constantly or intermittently reducing the pressure. 3. A resin tank for storing a liquid photocurable resin, a molding table arranged in the resin tank so that at least the upper surface is horizontal, and a moving means for vertically moving the molding table. Irradiating means for irradiating the liquid level of the photocurable resin with a laser beam based on the cross-sectional data of the article; An optical shaping apparatus comprising: a moving sweeping means; a driving means for moving the sweeping means; and a control means for driving the driving means in accordance with pre-programmed logical processing information.