JP2838663B2 - Stereolithography - Google Patents

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 for irradiating a photocurable resin with light energy in a desired arbitrary shape, laminating the obtained layered planar cured product, and forming a three-dimensional molded product. It is about.

[0002]

2. Description of the Related Art Conventionally, various photolithography methods for forming a three-dimensional molded article by irradiating photocurable resin with light energy have been known, and in particular, recently published by Nikkan Kogyo Shimbun. (Published October 30, 1990; authors: Yoji Marutani, Kazuo Okawa, Seiji Hayano, Naoichiro Saito, Takashi Nakai) have become widely understood.

As a conventional stereolithography method, a particularly general method is to provide a base plate as a molding table in a liquid near a resin liquid surface in an open-top resin tank storing a photocurable resin, and to provide the base plate with the base plate. By irradiating the upper resin free liquid surface with light from above, a first resin cured material layer is formed on the plate, and then the plate is moved downward in the tank by the thickness of the resin cured material layer. The method of lowering and irradiating the resin on the first resin cured material layer with light to form the second resin cured material layer is repeated, and the sliced resin cured material layer is continuously formed. This is a method of forming a desired three-dimensional shape by laminating, and in this method, the table in the tank is sequentially lowered from the free liquid surface of the resin and the molded object is formed while laminating the cured product, so that the free liquid surface method is used. Called.

[0004] As another method, a base plate as a modeling table is provided in a resin tank having a transparent bottom plate, and light is irradiated from the lower side of the resin tank through the transparent plate toward the base plate to form a base plate and a bottom plate. The resin between the transparent plate and the resin is cured as a first resin cured material layer, and then the base plate is pulled up to peel off the first resin cured material layer from the transparent plate on the bottom surface. The method of forming the second resin cured material layer between the resin cured material layer and the bottom surface by light from below the resin tank is repeated, and this method is based on the amount of resin cured by light irradiation. Is regulated between the base plate or the existing cured material layer and the bottom transparent plate of the resin tank, and is called a regulated liquid level method.

In this regulated liquid level method, a resin tank is formed as a tank type having a transparent plate on the bottom surface and capable of storing a large amount of photocurable resin, and a base plate is submerged in the resin tank near the transparent plate on the bottom surface. A lower exposure method in which the resin between the base plate and the transparent plate is irradiated with light through the transparent plate from below the tank to cure the resin between the two plates, and a laminated resin curing in which the bottom of the resin tank is made of a transparent plate. As a thin dish type that stores a small amount of resin equivalent to the thickness of the material layer, the base plate is brought into contact with the liquid surface in the resin tank, and the resin between this base plate and the transparent plate is transparent from the bottom of the tank. There is a thin liquid layer method in which light is irradiated through a plate to cure a resin between the two plates.

As the regulated liquid level method, in addition to the above,
The resin tank is a tank type that can store a large amount of photocurable resin composed of a base plate with an opaque base, and a container-shaped transparent plate with a transparent lower surface is submerged in the resin tank near the base plate on the bottom of the resin tank. There is an upper exposure method in which the resin between the transparent plate and the base plate is irradiated with light through the transparent plate from above the tank, and the resin between the two plates is cured. (Pages 78 to 83).

[0007]

According to the above-mentioned free liquid level method, a base plate is arranged near a resin liquid level in a resin tank having an open top, and light is directly applied to the resin free liquid level on the base plate from above. Since the resin cured material layer is formed on the base plate, the resin expands due to heat during the process of irradiating the resin on the base plate with light to form the resin cured material layer. The surface position fluctuates and the focus of light emitted from the light irradiation device shifts,
There is a problem that unevenness occurs in the lamination pitch of the cured resin layer formed due to the surface tension of the resin, and the cause of molding failure is likely to occur.

On the other hand, in the regulated liquid level method, since a limited amount of resin sandwiched between the base plate and the transparent plate is cured by light irradiation, the resin is not affected by heat, and It has the advantage that a molded article can be formed without changing the properties of the free liquid surface of the resin or the viscosity of the resin, and can compensate for the drawbacks of the free liquid surface method.

However, the regulated liquid level method having such advantages still has the following problems to be solved. That is, in the regulated liquid level method, a limited amount of resin in a tank interposed between the base plate and the transparent plate is cured, and therefore, in the lower exposure method and the thin liquid layer method, the resin is provided on the base plate or the base plate. If the lower surface of the existing resin cured product layer (the surface on which the next cured product layer is molded, the next layer molding surface) does not correctly correspond to the transparent plate on the bottom surface of the resin tank, and in the upper exposure method, the upper transparent plate or Unless the lower surface (next layer molding surface) of the existing resin cured material layer attached to this transparent plate is made to correctly correspond to the base plate serving as the bottom surface of the tank, the molding of the next resin cured material layer with respect to this next layer molding surface Does not work properly.

That is, of the above-mentioned regulated liquid level methods known in the art, for example, in the thin liquid layer method or the lower exposure method,
As shown in FIG. 6A, since the base plate 3 arranged with respect to the resin 2 in the resin tank 1 only moves up and down while maintaining a horizontal state by an elevating device (not shown), the next layer of the base plate 3 When the molding surface 3a is brought into contact with the resin surface in a horizontal state from above the outside of the resin 2, or when the bubbles 4 are mixed in the resin liquid in advance and the base plate 3
When the air bubbles 4 happen to be located on the lower surface of the next layer molding surface 3a when the next layer molding surface 3a comes into contact with the resin surface, these air bubbles 4 are removed from the next layer molding surface 3a. There is no way to remove it from the underside.

As shown in FIG. 6B, when the resin 2 on the lower surface of the next layer forming surface 3a is irradiated with light to form the cured resin layer 5 while leaving the bubbles 4, the base plate 3 and the cured resin layer 5 are formed. When the bubbles 4 intervene between the resin cured material layer and the lower surface of the existing resin cured product layer, the respective resin cured products to be molded are reduced. Many causes of poor adhesion are interposed between the lamination of layers, and defects such as dropping of a formed article, delamination, and poor dimensional accuracy in the laminating direction occur after the completion of the molding operation.

The problems caused by the above-mentioned bubbles are in the case of the downward exposure method and the thin liquid layer method.
Also in the upper exposure method, since the upper transparent plate is made to correspond to the base plate serving as the bottom surface of the tank, a similar problem occurs when bubbles in the resin liquid are located on the lower surface of the transparent plate.

[0013]

SUMMARY OF THE INVENTION The present invention has been developed for solving the problems of the stereolithography method based on the regulated liquid level method among the conventional stereolithography methods described above. In the invention according to claim 1, in the optical shaping method by the regulated liquid level method, as a pretreatment for forming the next resin cured material layer on the surface of the base plate or the existing resin cured material layer attached to the plate, After arranging the base plate or the existing resin cured product layer or the transparent plate in the resin liquid in an inclined manner in advance, the base plate or the existing resin cured material layer or the transparent plate is returned to a horizontal state and in a correct horizontal plane with respect to the resin liquid. It is characterized by being in contact with the liquid.

[0014] The invention of claim 2 relates to a thin liquid layer method in a regulated liquid level method, wherein the resin tank is a thin dish type corresponding to the thickness of a cured resin layer having a transparent plate on the bottom surface, After the base plate disposed on the resin liquid surface in the resin tank or the existing resin cured material layer attached to the plate is arranged in advance in the resin liquid in an inclined manner, the base plate or the existing resin cured material layer is placed in a horizontal state. It is characterized by being returned and brought into contact with the liquid.

The invention according to claim 3 relates to a downward exposure method in a regulated liquid level system, wherein the resin tank is of a tank type capable of storing a large amount of photocurable resin having a transparent plate on the bottom surface. The base plate placed in the resin liquid or the existing cured resin layer attached to the plate is tilted to a position sandwiching the resin thickness corresponding to the pitch of the laminated resin cured layer in advance corresponding to the transparent plate on the bottom surface. Then, the base plate or the existing cured resin layer is returned to a horizontal state and brought into contact with the liquid.

The invention according to claim 4 relates to an upper exposure method in a regulated liquid level system, wherein the resin tank is a tank type capable of storing a large amount of a photocurable resin having a bottom surface as a base plate. After disposing the transparent plate disposed in the resin liquid in advance at a position sandwiching the resin thickness corresponding to the pitch of the laminated resin cured product layer corresponding to the base rate of the bottom surface, the transparent plate is placed in a horizontal state. And the liquid is brought into contact therewith.

According to the fifth and sixth aspects of the present invention, the lifting device for vertically moving the base plate or the transparent plate in the regulated liquid level method in the Z-axis direction is rotated and tilted about the rotation axis to thereby incline the base plate. Alternatively, an existing resin cured material layer or a transparent plate is inclined in a resin liquid.

[0018]

According to the present invention, as a processing step for forming a cured resin layer in a resin tank, in the case of a thin liquid layer method and a downward exposure method, a base plate or an existing resin cured product adhered to the plate. The next layer molding surface on the lower surface of the layer, and in the case of the upper exposure method, the next layer molding surface on the lower surface of the transparent plate, both are arranged in the resin liquid in an inclined manner, so that the next layer molding surface and the resin liquid In the process where the inclined next-layer molding surface returns to a horizontal state in the liquid when bubbles are interposed between the other layers, the other end of the next-layer molding surface where the bubbles finally sink down horizontally along the inclined surface Can be extruded into the liquid from the side.As a result, air bubbles are prevented from intervening between the next layer molding surface and the resin liquid in the resin liquid, and bubbles are always generated between the next layer molding surface and the resin. The molding operation can be carried out in a state where no steel sheet is present.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an optical molding method using a regulated liquid level method according to the present invention will be described with reference to a molding apparatus of a thin liquid layer method shown in FIG. 1. Reference numeral 10 denotes a resin molding tank. A thin dish-shaped resin tank 11 for storing a predetermined amount of photocurable resin 13 having a bottom surface formed by a transparent plate 12, and a resin supply tank 14 provided in a groove shape around the resin tank 11. The molding base plate 1 that can move up and down is placed on the liquid surface of the photocurable resin 13 in the dish-shaped resin tank 11.
5 are arranged.

As shown in FIG. 2, the resin molding tank 10 is provided with a pump 16 outside the tank. Each time the resin is molded, a predetermined amount of light curing resin stored in the surrounding resin supply tank 14 is provided. After the volatile resin 13 is supplied into the dish-shaped resin tank 11 by the pump 16, the schema device 17 provided on the resin supply tank 14 moves horizontally along the upper edge of the resin tank 11. Then, the surplus resin 13 supplied into the resin tank 11 is returned to the resin supply tank 14, and the resin 13 is supplied into the resin tank 11 in an amount corresponding to the lamination slice pitch of the target laminated resin cured material layer. I do.

On the liquid surface of the photo-curable resin 13 supplied into the dish-shaped resin tank 11, the above-mentioned molding base plate 15 is horizontally disposed, and as shown in FIG. It is supported by an elevating device 19 provided on the outside of the tank via an arm 18, and is moved up and down with respect to the liquid level of the resin 13 by the elevating device 19. Is X that moves freely in the vertical and horizontal directions
A computer unit 2 for irradiating a laser beam from a light irradiating unit 22 to a photocurable resin 13 in a resin tank 11 through a bottom transparent plate 12 by a Y plotter 21
The light irradiation device 20 connected to the light irradiation device 3 is provided.

As the light irradiation device 20, a laser device for irradiating various laser lights such as a gas, a solid, and a semiconductor laser is used. In addition, the light irradiation device 20 and the XY plotter 21
Is controlled by the computer unit 23
Is an elevating device 1 for vertically moving the modeling base plate 15
9 and the pump 16, the schema device 17 and the like, and also calculates the plane shape of each laminated slice in the three-dimensionally formed object, and further draws the desired plane shape on the light irradiation device 20 so that Calculation of attribute data such as laser scan speed and scan pitch is also performed at the same time.

As shown in FIG. 3, in the elevating device 19 for the modeling base plate 15, an arm 18 supporting the plate 15 is moved up and down by a fluid cylinder or a screw rod. The lifting device 1 is mounted on a shaft so as to rotate in the left-right direction by 24 and holds the base plate 15 at a desired height position.
The base plate 15 can be inclined at a predetermined angle with respect to the liquid level of the resin 13 in the resin tank 11 by rotating the base 9 around the rotation shaft 24.

The procedure of the molding method using the above-described molding apparatus will be described. As shown in FIGS. 1 and 3a, after a predetermined amount of photocurable resin 13 is supplied into a thin dish-shaped resin tank 11, an elevating apparatus is provided. With 19, the molding base plate 15 is lowered on the liquid surface of the resin 13. At that time, base plate 1
Before contacting the entire surface of the next layer forming surface 25 on the lower surface of the resin 5 with the liquid surface of the resin 13, one of the elevating devices 19 is rotated around the rotation shaft 24, for example, to the right, so that the base plate 15 is horizontal. By slightly tilting the surface of the resin 13,
First, the next layer forming surface 25 on the one end 15a side of the plate is first descended so as to sink into the liquid surface of the resin 13.

After the base plate 15 is brought into contact with the liquid so that one end 15a is first sunk into the liquid surface of the resin 13, the rotating posture of the lifting / lowering device 19 is gradually shifted to the vertical position at that position as shown in FIG. 3b. By returning the base plate 15 to the horizontal state so that the other end 15b of the plate finally sinks into the resin liquid level, the base plate 15
The entire area of the next layer forming surface 25 in the above is surely settled in the liquid level of the resin 13.

Next, as shown in FIG. 3C, the plate 15 in the horizontal state is lifted by the elevating device 19 to a position where the next layer forming surface 25 of the plate 15 comes into contact with the liquid surface of the resin 13. On the lower surface, a space for the resin 13 corresponding to the desired laminated slice pitch A of the cured resin layer is formed.

As shown in FIG. 3B, after the entire area of the next layer forming surface 25 of the plate 15 is once submerged in the liquid of the resin 13 as shown in FIG. Is pulled up to a position where it comes into contact with the liquid surface of the resin 13. In this way, the entire area of the next layer forming surface 25 of the plate 15 is once submerged in the liquid of the resin 3 and then the plate 1
5 is raised to a position where the next layer molding surface 25 comes into contact with the liquid surface of the resin 13.
This is important as a method for eliminating air bubbles interposed between the resin 5 and the liquid level of the resin 13.

In the process from FIG. 3B to FIG. 3C, the lifting device 19 is rotated by turning the elevating device 19 from the state in which one end 15a side of the plate of FIG. Thus, the entire area of the next layer forming surface 25 of the base plate 15
However, as another method, from the state where one end 15a side of the plate is first submerged below the liquid surface of the resin 13, the plate 15 is further inclined and the bottom surface is raised by the elevating device 19. By descending to the contact depth, the entire area of the next layer molding surface 25 is surely settled below the liquid level of the resin 13,
The plate 15 may be returned horizontally to the liquid surface by pulling up the one end 15a side, which has been brought into contact with the liquid, up to a predetermined height in the liquid.

However, in this method, after the entire area of the next layer forming surface 25 of the plate 15 is submerged below the liquid level, the lifting device 1 for lifting the one end 15a, which has been brought into contact with the liquid, upward.
9 and the return operation of the rotation angle by the rotating shaft 24 must be performed simultaneously.
There is a problem that operation becomes complicated.

After the next layer forming surface 25 of the plate 15 is pulled up to a position where it comes into contact with the liquid surface of the resin 13 as shown in FIG. 3C, the light irradiating section 2 below the resin tank 11 is formed as shown in FIG.
2 irradiates light energy to the photocurable resin 13 in the tank 11 through the transparent plate 12 on the bottom surface to obtain a desired resin cured material layer 26a.

After the cured resin layer 26a is formed on the next layer forming surface 25 of the base plate 15, as shown in FIG.
By rotating the elevating device 19 or raising the elevating device 19, the cured resin layer 26a is separated above the liquid surface of the resin tank 11, and reduced by molding the cured resin layer 26a in the same manner as described above. The resin 13 is supplied into the resin tank 11 from the surrounding resin supply tank 14, and the schema device 1 is supplied.
7, the amount of the resin 13 in the resin tank 11 is adjusted. At this time, the base plate 15 is moved to a sufficient height above the resin tank 11 by the elevating device 19 so that the cured resin layer 26a does not hinder the operation of the schema device 17.

Next, as shown in FIG. 3F, the base plate 15 is moved by the elevating device 19 to the resin tank 1 in which the resin 13 has been supplied.
3A, and at the same time as in the case of FIG. 3A, the elevating device 19 is rotated by the rotating shaft 24 to incline the base plate 15, and one end of the inclined existing resin cured material layer 26a is Immersed in the liquid surface.

Thereafter, as in the case where the existing resin cured material layer 26a is formed as shown in FIG. 3B, the base plate 15 is returned to a horizontal position, so that the entire area of the next layer molding surface 25 of the existing resin cured material layer 26a is once liquid. After being settled in the surface, it is lifted upward to bring the next layer forming surface 25 of the existing cured resin layer 26a into contact with the liquid surface, and the light energy from the lower light irradiating portion 22 is passed through the transparent bottom plate 12 into the tank 11. By finally irradiating the photo-curable resin 13 to form the next cured resin layer, the intended laminated structure 27 as shown in FIG. 2 is finally formed.

FIG. 4 shows an embodiment of the downward exposure method in the regulated liquid level system. In this case, as shown in FIG. 4A, a base plate 35 is previously placed in a liquid in a resin tank 31 capable of storing a large amount of resin 33. After arranging the base plate 35 in the inclined state at a position sandwiching the resin thickness corresponding to the pitch of the laminated resin cured material layer with the bottom transparent plate 32, the base plate 35 is returned to a horizontal state as shown in FIG. Irradiation of light energy from below 31 forms the cured resin layer 46.

FIG. 5 shows an embodiment of the upward exposure method in the regulated liquid level method. In this case, as shown in FIG. 5A, the liquid in the resin tank 41 capable of storing a large amount of resin 43 having a base plate 45 as a bottom surface. A container-shaped transparent plate 42 having a transparent lower surface is disposed at a position corresponding to the base rate 45 of the bottom surface so as to sandwich the thickness of the resin corresponding to the pitch of the cured resin layer. 42 is returned to a horizontal state, and then light energy is irradiated through the upper transparent plate 42 to form a cured resin layer 56.

[0036]

As described above, according to the present invention, as a treatment step for forming a cured resin layer in a resin tank,
In the case of the thin liquid layer method and the lower exposure method, both the base layer or the next layer forming surface of the existing resin cured material layer attached to the plate, and in the case of the upper exposure method, the next layer forming surface of the transparent plate. The other side of the next layer molding surface, in which bubbles intervening between the next layer molding surface and the resin liquid are finally settled horizontally by returning to a horizontal state after being arranged in an inclined shape in the resin liquid. Can be extruded into the liquid to suppress the inclusion of bubbles, so that the molding operation can proceed efficiently without always worrying about the presence of bubbles.

In the first stage of molding, in the process of attaching and molding the resin cured material layer to the next layer molding surface of the base plate or the transparent plate, it is necessary to prevent bubbles from intervening between the next layer molding surface and the resin. As it can be suppressed, it is possible to make effective between the molding surface of the next layer of the base plate or the transparent plate and the cured resin layer to ensure a secure adhesion state, and in the process of molding, from the lower surface of the base plate or the transparent plate The problem that the resin cured material layer molded to some extent over the bending time falls and falls on the way can be surely solved.

Further, after the cured resin layer as a first step is formed on the molding surface of the next layer of the base plate or the transparent plate, the next cured resin layer is sequentially formed on the lower surface of the existing cured resin layer. Even in the process of the second and subsequent steps, it is possible to eliminate the presence of bubbles by the same method and to ensure the adhesion between the cured resin layers, so that the adhesive strength between the respective cured resin layers can be improved and the lamination direction can be improved. This has the advantage that the dimensional accuracy can be expected to be improved, the delamination of the cured resin layer can be reliably prevented in the end, and the practicality of the stereolithography method using the regulated liquid level method can be dramatically improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a basic mode of a stereolithography method using a regulated liquid surface method according to the present invention.

FIG. 2 is a perspective view of an optical shaping apparatus that performs a thin liquid layer method by a regulated liquid surface method according to the present invention.

FIG. 3 is a cross-sectional view showing a procedure when the stereolithography method of the present invention is performed by a thin liquid layer method.

FIG. 4 is a cross-sectional view when the stereolithography of the present invention is performed by a downward exposure method.

FIG. 5 is a cross-sectional view when the stereolithography method of the present invention is performed by an upper exposure method.

FIG. 6 is a cross-sectional view illustrating a conventional thin liquid layer method using a regulated liquid level method.

[Explanation of symbols]

 10, 30, 40: Resin molding tank 11, 31, 41: Resin tank 12, 32, 42: Transparent plate 13, 33, 43: Photocurable resin 14: Resin supply tank 15, 35, 45: Modeling base plate 16: Pump 17: Schema device 18: Arm 19: Pump 20: Light irradiator 21: XY plotter 22: Light irradiator 23: Computer unit 24: Rotating shaft 25: Next layer forming surface 26a, 26b, 46, 56: Resin Cured product layer 27: additive manufacturing

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B29C 67/00

Claims (6)

(57) [Claims] 1. A resin cured material layer is formed on a surface of a base plate by irradiating light energy through a transparent plate to a photo-curable resin in a resin tank interposed between a modeling base plate and a transparent plate. Is a stereolithography method using a regulated liquid level method of forming a three-dimensional object by sequentially laminating a resin cured material layer on the surface of the resin cured material layer, and the existing resin adhered to the base plate or the plate. As a pretreatment for forming the next resin cured product layer on the surface of the cured product layer, the base plate or the existing resin cured product layer or the transparent plate is arranged in a resin solution in advance in an inclined manner, and then the base plate or the existing An optical shaping method characterized by returning a cured resin layer or a transparent plate to a horizontal state and contacting the resin liquid with a correct horizontal surface. 2. The resin tank has a thin plate shape corresponding to the thickness of a cured resin layer having a transparent plate on the bottom surface, and a base plate disposed on a resin liquid surface in the resin tank or an existing plate attached to the plate. The stereolithography method according to claim 1, wherein the cured resin layer is arranged in advance in the resin liquid in an inclined manner, and then the base plate or the existing cured resin layer is returned to a horizontal state and brought into contact with the liquid. 3. The resin tank is a tank type having a transparent plate on the bottom surface and capable of storing a large amount of photocurable resin, and a base plate disposed in a resin liquid in the resin tank or an existing resin cured product adhered to the plate. After arranging the layers in advance at a position sandwiching the resin thickness corresponding to the pitch of the laminated resin cured product layer corresponding to the transparent plate on the bottom surface, the base plate or the existing resin cured product layer is returned to a horizontal state. The stereolithography method according to claim 1, wherein the liquid is brought into contact with the liquid. 4. The resin tank is of a tank type having a base plate serving as a base plate and capable of storing a large amount of photocurable resin, and a transparent plate disposed in a resin liquid in the resin tank corresponds to a base rate of the bottom surface in advance. The stereolithography method according to claim 1, wherein the transparent plate is returned to a horizontal state and is brought into contact with the liquid after being disposed in an inclined manner at a position sandwiching the resin thickness corresponding to the pitch of the laminated resin cured material layer. 5. The apparatus according to claim 1, wherein the elevating device for moving the base plate in the Z-axis direction is rotated and tilted about a rotation axis to tilt the base plate or the existing resin cured material layer with respect to the resin liquid level. Stereolithography. 6. The stereolithography method according to claim 4, wherein the lifting / lowering device for moving the transparent plate in the Z-axis direction is rotated and tilted about a rotation axis to tilt the transparent plate with respect to the resin liquid level.