JPH071595A - Optical molding apparatus - Google Patents

Abstract

PURPOSE:To avoid the generation of unnecessary hardened material at the upper surface of a protruding part and to prevent peeling of layers by supplying light- hardening resin into a resin molding cell, molding the resin, thereafter separating a molding base plate upward, the lowering the plate once to a position where the hardening material layer sinks beneath the surface of resin liquid, thereafter lifting the plate to the thickness of the hardening material layer. CONSTITUTION:After a hardening material layer 20a is molded in a molding cell 11, a lower surface 18a of a molding base plate 18 is lifted and separated to a height B, where the alignment of the height of the surface of the resin liquid with a smoothing plate 29 of a skimmer device 22 is not hindered, from a liquid level position A. Then, the plate lower surface 18a of the molding base plate 18 is returned to the liquid level A once. Thereafter, the plate lower surface 18a is lifted to the position of z-p. Under this state, the hardening material layer 20a at the lower surface of the molding base plate 18 is lowered to a position, where the layer 20a sinks beneath the resin liquid level A. Therefore, the lower surface of the already provided hardening material layer 20a and the resin liquid level A come into secure contact. In this way, the second hardening material layer can be laminated at the lower surface of the first hardening material layer 20a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention irradiates a photocurable resin in a tank with light energy from a light irradiation device from below a photocurable resin molding tank whose bottom surface is a transparent plate. A cured product layer of resin is molded on the lower surface of the modeling base plate arranged on the liquid surface, and the modeling base plate is moved in a direction away from the transparent plate of the modeling tank, whereby the cured product layer is sequentially laminated on the modeling base plate. The present invention relates to an improvement of the optical modeling method of molding a shaped object.

[0002]

2. Description of the Related Art Conventionally, various types of stereolithography have been known as a stereolithography method for molding a three-dimensional sculpture by irradiating a photocurable resin in a sculpting tank with light energy. As a widely known method, as described in pages 79 to 83 of "Stereolithography" by Yoji Marutani, 4 publications, published by Nikkan Kogyo Shimbun on October 30, 1990. , A free liquid surface method that irradiates light from above the liquid surface created by the photocurable resin to form a molded object in which a cured product layer is laminated, and a space between the transparent plate and the molding base plate There is a regulated liquid level method in which a molded article in which a cured product is laminated is sequentially formed by irradiating light through a transparent plate so as to match the thickness of the regulated liquid level.

In the above-mentioned free liquid level system, the molding stage is arranged slightly below the liquid level in the molding tank in which the photo-curable resin is stored, and the light irradiation device is provided above the molding tank. By irradiating the photocurable resin in the tank with light energy, a cured product layer is formed on the upper surface of the modeling stage, and then the position of the modeling stage is slightly lowered to lower the resin on the surface of the already cured layer. Is flowed, and the liquid surface of the resin filled by this flow is irradiated with light to form the next cured product layer, thereby repeating the process of forming the desired layered product.

On the other hand, in the regulated liquid level system, the photocurable resin stored in the tank is irradiated with light energy from a light irradiation device from below the photocurable resin molding tank whose bottom surface is a transparent plate. The cured product layer of the resin is formed on the lower surface of the molding base plate disposed on the liquid surface of the resin, and the next cured product is formed on the lower surface of the molding base plate by pulling the molding base plate away from the transparent plate of the molding tank. By repeating the process of forming layers, the target laminate-molded article is formed.

[0005]

In the former optical molding method based on the free liquid surface method, the resin on the molding base plate disposed slightly below the liquid surface of the resin in the molding tank is irradiated with light from above. Therefore, after molding the cured product, in order to form the next cured product layer on the upper surface of the cured product, the modeling base plate is sunk by a depth corresponding to the thickness of the cured product layer to be molded. In this case, simply submerging the modeling base plate to a predetermined depth does not allow the resin to be evenly and smoothly supplied to the surface of the already-cured product layer due to the action of the viscosity and surface tension of the resin itself, Since a predetermined time is required until the supplied resin becomes even and smooth, there is a problem that the next cured product layer cannot be efficiently and continuously formed.

Further, in the optical molding method using the free liquid surface method, since the molding base plate is sequentially submerged according to the molding of the cured material layer, it is necessary to store a large amount of resin in the molding tank in advance. As described above, in order to form the cured product layer near the liquid surface in the molding tank that stores a large amount of resin in this way, the resin temperature in the tank is constantly controlled to a predetermined temperature to control the resin viscosity. In addition, if the change in the liquid level due to thermal expansion or contraction of the resin is not prevented, the resin may not be supplied properly during the process of sinking the molding base plate, or peeling may occur between the cured product layers to be molded. There is a problem in that the tank must be equipped with a heating device such as an electric heater and the temperature must be constantly monitored.

On the other hand, in the latter optical molding method using the regulated liquid level system, a cured material layer is provided between the molding base plate disposed inside the tank by irradiating light from below the resin molding tank having a transparent bottom surface and the bottom surface of the tank. After molding, the modeling base plate is sequentially pulled up, and between the existing cured product layer and the transparent plate on the bottom surface of the tank, the cured product layer is sequentially molded by the predetermined resin volume stored in the tank in advance. Therefore, without being affected by factors such as the properties of the free liquid surface of the resin in the molding tank and the resin viscosity,
It has an advantage that a desired molded article can be molded and a molded article having a large shape can be molded in proportion to the capacity of the molding tank.

However, by the stereolithography method based on the regulated liquid level method, for example, as shown in FIG. 5, the first-layer cured product already molded in the resin molding tank 1 in which the photocurable resin 3 is stored. 4 has an outer edge 4a of the second layer cured product 5
It is overhanging with respect to a, and the outer edge 6a of the third layer cured product 6 is projected on the lower surface of the second layer cured product 5 more than the outer edge 5a of the second layer cured product 5. When molding a laminate-molded product of a different design, irradiate the resin 3a in the tank in the region outside the outer edge 5a of the second layer cured product 5 with light through the transparent plate 2 on the bottom surface. become.

In this case, even if the light to be irradiated is a shallow curing depth such as an ultraviolet laser, the curing depth of the light is higher than the intended layer thickness of the third layer cured product 6, that is, the first layer. Since it also extends to the resin 3a in the tank in the region outside the outer edge 5a of the second layer cured product 5, the third layer protruding outside the outer edge 5a of the second layer cured product 5 There arises a problem that an unnecessary hardened material 6c having a thickness t is attached and molded on the upper surface of the protruding portion 6b of the eye hardened material 6.

On the other hand, in the method of forming a desired molded article by sequentially laminating a cured article layer having a predetermined layer thickness as in the stereolithography method, between the respective laminated cured article layers 4, 5 and 6. In order to effectively adhere to each other and prevent delamination, for example, it is necessary to have a predetermined rooting depth corresponding to the thickness t of the unnecessary cured product 6c shown in FIG. I can say.

However, in the conventional regulated liquid surface type optical molding method, as shown in FIG. 5, the cured material layers 4, 5 are successively formed by the predetermined volume of the resin 2 previously stored in the resin molding tank 1. Since 6 is molded, the outer edge 5a as described above is formed.
When molding a layered product having a design in which the outer edge 6a has the next layer 6 projecting from the front layer 5 under the retracted front layer 5, the outer edge 6a projects the next layer from the front layer 5 Part 6
As long as the resin 3a in the molding tank is present on the upper surface of b and the resin 3a in this portion is irradiated with light, even if an ultraviolet laser having a shallow curing depth is used, the upper surface of the next layer protruding portion 6b is It is inevitable that the unnecessary hardened material 6c corresponding to the thickness t is generated, which has a fatal defect that causes defective molding.

[0012]

SUMMARY OF THE INVENTION In view of the problems of the conventional stereolithography method as described above, the present invention provides an outer edge for the purpose of forming a laminated cured product layer having a predetermined layer thickness by a regulated liquid level method. Under the retracted front layer, when molding the next layer whose outer edge protrudes more than the front layer, without generating an unnecessary cured product along with the curing depth by the light irradiation device on the upper surface of the next layer protrusion, The object is to provide an optical modeling method capable of freely molding a desired three-dimensional layered product.

The stereolithography method according to the present invention is, as a concrete means for achieving the above object, a photo-curing of an amount corresponding to the layer thickness of the laminated cured product in a resin modeling tank having a transparent plate on the bottom. After storing the plastic resin, the molding base plate arranged above the molding tank is brought into contact with the resin liquid surface of the molding tank, and the resin in the molding tank is irradiated with light from below the molding tank to form the molding base plate. In the stereolithography method by the regulated liquid surface method that molds a cured product layer of a predetermined layer thickness on the lower surface of
After supplying the photocurable resin in an amount larger than the layer thickness of the cured product once in the resin modeling tank, the surface of the resin is uniformly adjusted to a predetermined liquid level by a leveling plate or the like, When a cured product layer having a predetermined layer thickness is molded in the modeling tank by light irradiation and then the modeling base plate is moved by a distance corresponding to a layer thickness P for molding the next cured product layer, the modeling base plate is formed. Is moved to a predetermined height position where the height of the resin liquid surface is adjusted by the leveling plate or the like, and then the molding base plate is a position where the cured product layer on the lower surface sinks below the resin liquid surface in the molding tank. It is characterized in that the shaping base plate is raised from the lowered position to a distance corresponding to the layer thickness P at which the next cured product layer is formed.

[0014]

According to the stereolithography method of the present invention, the photocurable resin in an amount larger than the layer thickness of the cured product is once supplied into the resin molding tank, and the surface of the resin is leveled with a leveling plate or the like. Since the height is uniformly adjusted to the height, the resin stored in the modeling tank can always be maintained at a predetermined liquid level at which a desired cured product of one layer can be obtained. Therefore, when molding the next layer with the outer edge protruding more than the front layer under the front layer with the outer edge retracted as described above, the upper surface of the next layer protruding portion is made as a space where no resin exists, It is possible to prevent unnecessary cured products from being generated on the upper surface of the next-layer protruding portion even when subjected to the curing action of the light irradiation device.

Further, after a hardened material layer having a predetermined thickness is formed in the molding tank by light irradiation, the molding base plate is moved by a distance corresponding to a layer thickness P for molding the next hardened material layer. However, at that time, after moving the modeling base plate to a height position Z where the leveling plate or the like does not hinder the adjustment of the height of the resin liquid surface, the modeling base plate is moved to the existing cured product on the lower surface. Since the layer is once lowered to a position where it is submerged below the resin liquid level in the molding tank, it is raised to a distance corresponding to the layer thickness P at which the next cured material layer is formed.
The existing cured material layer and the lower resin liquid surface can be reliably brought into contact with each other without a gap due to the surface tension. Therefore, even when molding the molded article of the special design as described above, the upper surface of the protruding portion of the next layer is formed. It is possible to provide an effective fixing state in which no unnecessary hardened material is generated and the interlayer separation does not occur between the hardened material layers that are sequentially laminated.

[0016]

EXAMPLES Next, the stereolithography method according to the present invention will be described with reference to the examples shown in the drawings. FIG. 2 shows a molding apparatus used for carrying out the stereolithography method, and the resin molding tank 11 is provided in the vicinity thereof. Is a relatively shallow dish shape with a relatively small depth surrounded by a gutter-shaped resin recovery groove 14, and the bottom surface is made of a transparent plate 12 such as transparent glass.
On the lower side of the computer 1, a light irradiation device 15 for irradiating the photocurable resin 13 in the molding tank with light energy is provided.
6 is provided via a drive device 17 that is movable in the X, Y, and Z axis directions by the control of 6, and the liquid level of the photocurable resin 13 is moved in the vertical direction by the control of the computer 16. A possible shaping base plate 18 made of a glass plate or the like is arranged.

Further, the peripheral edge portion 19 which forms the periphery of the transparent plate 12 in the resin molding tank 11 is adjusted to a height corresponding to the thickness of the cured resin layer 20 described later. The resin molding layer 1 on the upper edge of
A skimmer device 22 for uniformly leveling the surface of the photocurable resin 13 that is supplied and filled in the modeling tank 11 by moving from one side to the other side of 1 is provided.
Further, in the resin molding tank 11, the gutter-shaped resin recovery groove 14 provided around the molding tank is used to supply and recover the photocurable resin 13 into and out of the molding tank 11. Is provided.

Circulating device 21 for supplying and recovering the resin
Is operated by the skimmer device 22 and the resin recovery groove 14 that is integral with the peripheral edge portion 19 that forms the periphery of the resin molding tank 11, and the resin recovery groove 14 is removed from the inside of the resin molding tank 11 by the operation of the skimmer device 22.
A resin circulating tank 2 for temporarily storing the resin 13 flowing into the outside of the resin modeling tank 11 via a circuit 24.
3 and the resin 13 in the resin recovery groove 14 are sent to the resin circulation tank 23, and the resin 13 in the resin circulation tank 23 is again supplied to the resin molding tank 11 via the supply nozzle 26.
It is composed of a circulation pump 25 for feeding inward.

Further, the skimmer device 22 is connected to the belt 28, which is rotated by a drive motor 27 arranged in parallel with the side surface of the resin molding tank 11 and is connected to the belt 28.
The molding tank 11 is in contact with the peripheral portion 19 of the molding tank 11
Moving from one side to the other side, the surplus amount of the resin 13 supplied from the resin circulation tank 23 into the modeling tank 11 is discharged into the surrounding resin recovery groove 14, and the resin inside the molding tank 10 is discharged. 1
2 and a leveling plate 29 for always matching the height of the peripheral portion 19 of the modeling tank.

Next, the stereolithography method of the present invention will be described with reference to FIG.
As shown in a, the resin 13 is supplied onto the transparent plate 12 in the molding tank 11, and the leveling plate 29 of the skimmer device 22 causes the surface of the resin 13 to match the height of the molding tank peripheral portion 19. When the position is adjusted, the resin 13 corresponding to one layer of the layering step of the layered product is stored in the modeling tank 11. Therefore, the modeling base plate 18 is brought into contact with the liquid surface of the resin 13 to perform modeling. Light energy is irradiated from the light irradiation device 15 below the tank 11 through the transparent plate 12 to form the first cured product layer 20a.

After the hardened material layer 20a is molded in this manner, as shown in FIGS. 1 and 3b, the lower surface 18a of the modeling base plate 18 is moved from the liquid surface position indicated by A to the leveling plate of the skimmer device 22. 29 is lifted and retracted to a height position B having a distance z that does not hinder the adjustment of the height of the resin liquid surface. In FIG. 1, the retreat distance z is based on the lower surface 18a of the molding base plate 18, but in reality, since the cured product layer is sequentially laminated on the lower surface of the molding base plate 18, the molding base plate 18 is formed.
Even when the laminate-molded article of a predetermined length is finally formed on the lower surface of the, the distance is set to a height that does not hinder the adjustment of the resin liquid level by the leveling plate 29.

When the hardened material layer 20a is formed on the lower surface of the molding base plate 18 as described above, the molding tank 1
Since the resin 13 in 1 consumes the volume corresponding to the hardened material tank 20a, new resin 13 is replenished in the modeling tank 11 as shown in FIG. 3c. When replenishing this new resin 13, the resin is supplied so as to be higher than the peripheral portion 19 of the molding tank, and then the excess resin is discharged by the leveling plate 29 of the skimmer device as shown in FIG. The height of the liquid surface corresponds to the layer thickness P for forming a predetermined hardened material layer.

Next, as shown in FIGS. 1 and 3c, the modeling base plate 18 is moved from the height position B to the modeling tank 1 as described above.
1 is lowered in the direction of the liquid level A. At that time, as shown in FIG. 1, the distance for descending the modeling base plate 18 is the position where the lower surface of the existing cured material layer 20a contacts the liquid surface of the resin 13,
That is, when the lower surface 18a of the molding base plate 18 is used as a reference, z is obtained by subtracting the resin layer thickness p from the distance z.
The position of −p may theoretically be acceptable. However, the descending distance of the modeling base plate 18 is set to the lower surface 18 of the plate.
When a is at the z-p position, that is, when the lower surface of the existing cured product layer 20a is in contact with the liquid surface A, there may be a case where the molding of the second cured product layer cannot be reliably performed. .

That is, as described above, when the lowering distance of the modeling base plate 18 is stopped at the position where the plate lower surface 18a is zp, theoretically, the lower surface of the existing cured material layer 20a is the liquid surface A. Since they come into contact with each other, by irradiating light from below the modeling tank 11 in this state, the second cured product layer can be laminated on the lower surface of the existing cured product layer 20a. However, in reality, the resin liquid layer thickness p in the modeling layer is usually a thin layer of about several millimeters, the liquid level accuracy is not uniform, and the fine movement of the modeling base plate 18 requires skill. Under some conditions, it may not be possible to accurately bring the lower surface of the existing cured product layer 20a into contact with the liquid surface A. Under such unfavorable conditions, the light may be irradiated from below to the inside of the modeling layer. Even when the next cured product layer is molded, the cured product layer and the existing cured product layer are not completely fixed to each other, and the layered product may be cut off during the molding.

Therefore, when the modeling base plate 18 is lowered, the modeling base plate 18 is returned to the same distance z as the plate lower surface 18a once moved, that is, the position of the liquid surface A, and then the modeling base plate 18 is moved.
Is raised to a distance where the plate lower surface 18a corresponds to the resin liquid layer thickness p, that is, the position of zp. In this state, the existing hardened material layer 20a on the lower surface of the modeling base plate 18 once descends to a position where the existing hardened material layer 20a completely sinks below the resin liquid level A in the modeling tank, and then the lower surface of the existing hardened material layer 20a is changed to the resin liquid level Since it rises to the position where it comes into contact with, the lower surface of the existing hardened material layer 20a that has been pulled up and the liquid surface A of the resin in the molding tank are surely in contact with each other due to the surface tension of the liquid.

Therefore, in this state, by irradiating the resin 13 in the tank from the lower surface of the molding tank with light, as shown in FIG. 3d, the lower surface of the first cured material layer 20a is covered with the second cured material. The layer 20b can be laminated and formed, and the subsequent cured product layer 20c is laminated and formed on the lower surface of the existing cured product layer 20b as shown in FIG.

[0027]

As described above, the optical modeling apparatus according to the present invention has the modeling base plate or the ready-made cured material layer in which the resin in the modeling tank is leveled with the skimmer device at the same height as the peripheral portion of the modeling tank. The resin between the transparent base plate or the preformed cured material layer and the transparent plate is irradiated with light from below through the transparent plate on the bottom surface, so that the shape of each lamination step to be formed is as shown in FIG. 4, the outer layer 5a is below the front layer 20b that is retracted, and the outer layer 6a is next to the front layer 20b.
Even in the case of molding, the upper surface of the next layer projecting portion 6b can be a space where no resin exists, and therefore, even if the next layer projecting portion 6b is cured by the light irradiation device from below.
It is possible to realize modeling that is not affected by the curing depth of the light irradiation device without generating an unnecessary cured product on the upper surface of b, and it is possible to increase the practical possibility of this type of optical modeling device. .

Further, after the hardened material layer in the molding tank is molded, the molding base plate is moved to such a height position that the leveling plate of the skimmer device does not hinder the leveling of the resin liquid surface. After that, the molding base plate is once lowered to a position where the existing hardened material layer on the lower surface sinks below the liquid surface of the resin in the molding tank, and then rises to a distance where the lower surface of the existing hardened material layer contacts the liquid surface. By doing so, the existing cured material layer and the lower resin liquid surface can be reliably contacted with each other without a gap due to the surface tension. Therefore, even when molding the shaped article of the special design as described above, the next layer It is possible to provide an effective fixed state in which no unnecessary cured product is generated on the upper surface of the protruding portion, and moreover, delamination does not occur between the cured product layers that are sequentially laminated due to the depth of rooting.

[Brief description of drawings]

FIG. 1 is a partially enlarged cross-sectional view of a modeling tank illustrating a molding step of a cured product layer in a stereolithography method of the present invention.

FIG. 2 is a partially cutaway perspective view showing a configuration of a modeling apparatus used in the optical modeling method of the present invention.

FIG. 3 is an explanatory view showing a molding step of a cured product layer in the stereolithography method of the present invention.

FIG. 4 is a partially enlarged cross-sectional view showing a molded state of a cured product layer by the stereolithography method of the present invention.

FIG. 5 is a sectional view showing an example of a conventional stereolithography method.

[Explanation of symbols]

11: Resin modeling tank 12: Transparent plate 13: Photocurable resin 14: Resin recovery groove 15: Light irradiation device 16: Computer 17: Driving device 18: Modeling base plate 19: Modeling tank peripheral part 20a, 20b, 20c: Hardened material Layer 21: Circulation device 22: Schematic device 23: Resin circulation tank 24: Circuit 25: Circulation pump 26: Supply nozzle 27: Drive motor 28: Belt 29: Leveling plate z: Modeling base plate moving distance p: Resin liquid layer thickness A : Liquid level B: Modeling base plate rising position

[Procedure amendment]

[Submission date] August 3, 1993

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 1]

[Fig. 2]

[Figure 3]

[Figure 4]

[Figure 5]

Claims (1)

[Claims] 1. A resin molding tank whose bottom surface is a transparent plate stores a photocurable resin in an amount corresponding to the layer thickness of a laminated cured product, and then a molding base plate arranged above the molding tank is used as the molding tank. Of the resin in the molding tank by irradiating the resin in the molding tank with light from below the molding tank to form a cured product layer having a predetermined thickness on the lower surface of the molding base plate. In the above, once a photocurable resin in an amount larger than the layer thickness of the cured product is supplied into the resin modeling tank, and the surface of the resin is uniformly adjusted to a predetermined liquid level by a leveling plate or the like. From the above, when a cured product layer having a predetermined layer thickness is formed by irradiation with light in the modeling tank, and then the modeling base plate is moved by a distance corresponding to a layer thickness P for forming the next cured product layer, Apply the modeling base plate to the leveling plate, etc. After moving to a predetermined height position where the height of the resin liquid level is adjusted, then the molding base plate is once lowered to a position where the cured product layer on the lower surface sinks below the resin liquid level in the molding tank, A stereolithography method, characterized in that the shaping base plate is raised from the lowered position to a distance corresponding to a layer thickness P at which a next cured material layer is formed.