JPH0790603B2 - Stereolithography device - Google Patents

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 a stereolithography apparatus of a type that molds 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 Maruya, four authors, 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 this regulated liquid level method, for example, as shown in FIG. 6, the first layer cured product already molded in the resin molding tank 1 storing the photocurable resin 3 therein. 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 article of a different design, irradiate light through the transparent plate 2 on the bottom surface to the resin 3a in the tank in the region outside the outer edge 5a of the second-layer cured product 5. Therefore, there arises a problem that the unnecessary hardened material 6c is adhered and molded on the upper surface of the protruding portion 6b of the third hardened material 6 which is projected outward from the outer edge 5a of the second hardened material 5.

In this way, when the next layer having the outer edge protruding more than the front layer is formed below the front layer with the outer edge retracted,
The unnecessary hardened material is attached and molded on the upper surface of the protrusion of the next layer.
Even when an ultraviolet laser is used for light irradiation,
Even when a semiconductor laser is used, there is a difference in the curing depth, but the same occurs.

As shown in FIG. 7a, when the curing profile of the photocurable resin due to the difference between the case where an ultraviolet laser is used and the case where a semiconductor laser is used as a light irradiation device is seen, for example, an Ar (argon) laser, He -C
In the case of an ultraviolet laser such as a d (helium-cadmium) laser, the curing depth is shallow, and the depth h with respect to the width t1.
While the relationship of 1 is about 1: 0.5 to about 3, as shown in FIG. 7b, in the case of the semiconductor laser, the curing depth is deep, and the relationship of the depth h2 to the width t2 is from 1:50. It has a feature of about 200, and the time until the depth h2 reaches about 50 mm is several seconds to ten and several seconds.

Therefore, when an ultraviolet laser is used as the light irradiation when molding the next layer having the outer edge protruding from the front layer under the front layer having the outer edge retracted as shown in FIG. Even if the curing depth is shallower than in the case of a semiconductor laser, as shown in FIG. 8, a third layer cured product 6 having a layer thickness T, which protrudes outside the outer edge 5a of the second layer cured product 5, is formed. An unnecessary hardened material 6c having a thickness t is attached and molded on the upper surface of the protruding portion 6b.

Similarly, when a semiconductor laser is used for light irradiation, since the curing depth is deeper than that of the ultraviolet laser, as shown in FIG. 9, the second layer cured product 5 is harder than the outer edge 5a. On the upper surface of the protruding portion 6b of the third layer cured product 6 having a layer thickness T protruding outward, an unnecessary cured product 6d having a thickness t far greater than the layer thickness T of the third layer cured product 6 is formed. Will be adhered and molded.

On the other hand, in the method of forming a desired shaped article by sequentially laminating a cured material layer having a predetermined layer thickness as in the stereolithography method, as shown in FIG. 8 and FIG. In order to effectively fix the cured product layers 4, 5 and 6 and prevent delamination, for example, a predetermined rooting depth corresponding to the thickness t of the unnecessary cured product 6c shown in FIG. 8 is set. It is necessary to have it.

In this way, considering the necessity of fixing the layers of the laminated cured products to each other with a predetermined depth of penetration, even when the ultraviolet laser having a shallow curing depth is used, as shown in FIG. As shown in FIG. 5, a predetermined depth of penetration corresponding to the thickness t of the unnecessary cured product 6c can be provided between the cured product layers having the layer thickness T, which is preferable in the sense that delamination can be prevented. Can be said.

However, in the conventional regulated liquid surface type optical molding method, as shown in FIGS. 6 and 8, a cured material layer 4 is sequentially formed by a predetermined volume of the resin 2 previously stored in the resin molding tank 1. , 5, 6 are formed, a layered product having a design having the next layer 6 in which the outer edge 6a projects more than the front layer 5 is formed under the front layer 5 in which the outer edge 5a is retracted as described above. In this case, the resin 3a in the molding tank is present on the upper surface of the next layer protruding portion 6b having the outer edge 6a protruding more than the front layer 5,
As long as the resin 3a in this portion is irradiated with light, an unnecessary cured product 6c corresponding to the thickness t is generated on the upper surface of the next layer protruding portion 6b even if an ultraviolet laser having a shallow curing depth is used. Inevitably, there is a fatal defect that causes defective modeling.

[0016]

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 apparatus capable of molding a desired three-dimensional layered product.

As a concrete means for achieving the above-mentioned object, the stereolithography apparatus of the present invention has the photocurable resin below the resin molding tank in which the photocurable resin having a transparent bottom plate is stored. A stereolithography by a regulated liquid level method, which includes a light irradiation device that is movable in the horizontal and vertical directions for curing the resin, and a molding base plate for stacking and fixing the molded object above the resin molding tank. In the apparatus, in the resin molding tank, a resin supply and recovery circulation device for uniformly supplying a photocurable resin in an amount corresponding to the layer thickness of the layered molded article into the molding tank, and a resin liquid level A skimmer device is provided.

[0018]

The stereolithography apparatus according to the present invention is a laminated molding product on the upper surface of the transparent plate in the resin molding tank by the circulation device for supplying and collecting resin provided in the resin molding tank and the schema device for the resin liquid level. Since it is possible to stably supply the photocurable resin in an amount corresponding to one layer of the cured product layer, the outer layer protrudes below the front layer and the outer layer protrudes from the front layer. At the time of molding, as the upper surface of the next layer protrusion is a space where no resin exists, an unnecessary cured product does not occur on the upper surface of the next layer protrusion even when subjected to a curing action by a light irradiation device from below, Therefore, it is possible to always form the cured product layer of each layer constituting the layered product to a stable and accurate thickness.

[0019]

EXAMPLE Next, the structure of the optical molding apparatus according to the present invention will be described with reference to the example shown in the drawing. As shown in FIG. 1, the resin molding tank 11 has a gutter-shaped resin recovery groove 14 around its periphery. It has a relatively shallow dish shape surrounded by a relatively small depth, and has a transparent plate 12 such as transparent glass on the bottom surface. Under the resin molding tank 11, a photocurable resin in the molding tank is provided. A light irradiator 15 for irradiating the resin 13 with light energy is controlled by the computer 16 so that X, Y,
It is provided via a drive device 17 that is movable in the Z-axis direction, and further, the liquid surface of the photocurable resin 13 can be moved in the vertical direction by the control of the computer 16.
A modeling 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, and these peripheral edge portions 19 are formed. 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.

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.

FIG. 3 shows another embodiment of the skimmer device. The skimmer device 30 of this embodiment has a lower edge via a bracket 33 in front of a leveling plate 31 that moves from one side to the other side of the modeling tank 11 while contacting the peripheral portion 19 of the resin modeling tank 11. The drainage plate 32 is integrally attached so that the liquid comes in contact with the upper surface of the transparent plate 12, and
The leveling plate 31 is provided with a resin supply nozzle 34 for supplying the resin 13 sent from the resin circulation tank 23 into the modeling tank 11 from between the leveling plate 31 and the drainage plate 32. ing.

In this skimmer device 30, when the leveling plate 31 and the drainage plate 32 are moved in the direction of the arrow at the time when the formation of a predetermined hardened material layer is completed, the drainage plate 32 is placed in the molding tank 11. All the remaining resin 13 is discharged into the resin recovery groove 14. Meanwhile, new resin 13 is replenished into the molding tank 11 from the resin supply nozzle 34 attached to the rear leveling plate 31, and the surplus amount of the replenished resin 13 is fed into the resin recovery groove 14 by the leveling plate 31. The resin in the molding tank 11 is discharged and maintained in an appropriate amount.

The molding process of the laminated cured product by this optical modeling apparatus will be described. As shown in FIG. 4A, the resin 13 is supplied onto the transparent plate 12 in the modeling tank 11, and the skimmer device 22 or 30 is used. When the surface of the resin 13 is adjusted to a position that matches the height of the peripheral portion 19 of the modeling tank, the resin 13 corresponding to one layer of the layering step of the layered model is stored in the modeling tank 11, The molding base plate 18 is brought into contact with the liquid surface of the resin 13, and light energy is irradiated from the light irradiation device 15 below the molding 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 FIG. 4b, the molding base plate 1 is formed.
8 is raised and retracted to a position where there is no hindrance to traveling of the skimmer device 22. When the desired hardened material layer 20a is molded, the resin 13 in the modeling tank 11 consumes the volume corresponding to the hardened material tank 20a. Therefore, new resin 13 is replenished in the modeling tank 11.

When the new resin 13 is replenished into the molding tank 11, the new resin 13 is replenished on the resin 13 remaining after the first cured product layer 20a is molded. However, at that time, for example, by using the skimmer device 30 shown in FIG. 3, all the resin 13 remaining in the tank is once discharged to the outside of the tank, and the resin 13 in the tank is entirely replaced with the new resin 13
It is preferable to replace with.

The reason is that the resin 13 left after the desired cured material layer 20a is molded is hardened by being exposed to a laser beam to some extent, so that the resin 13 on the old resin 13 is hardened. When new resin 13 is supplied to
This is because a difference in viscosity is caused between the old resin and the new resin, and unfavorable curing conditions are given when the next cured product layer is molded by irradiating light in that state.

As shown in FIG. 4c, when the new resin 13 is replenished in the molding tank 11, the resin 13 is supplied so as to be higher than the peripheral portion 19 of the molding tank, and then the leveling plate 29 of the skimmer device as described above. After discharging the surplus resin by, the modeling base plate 18 is lowered to bring the existing cured material layer 20a into contact with the liquid surface of the resin 13 as shown in FIG.
b is laminated. By repeating the same steps as described above, the next cured product layer 20c is laminated on the lower surface of the existing cured product layer 20b as shown in FIG. 4e.

[0030]

As described above, the optical modeling apparatus according to the present invention has the modeling base plate or the existing hardened material layer in which the resin in the modeling tank is leveled with the skimmer device to the same height as the peripheral portion of the modeling tank. The resin between the molding base plate or the existing cured product 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. 5, the outer layer 5a is below the front layer 20b, and the outer layer 6a is below 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, even if the amount of exposure by the light irradiation device becomes excessive, it is possible to prevent excessive depth hardening and molding defects due to mutual proximity hardening of the resin due to resin retention and the like, and at the same time, molding of resin with a small capacity is possible. Because it can be a tank,
The amount of resin to be supplied into the tank is always limited to the amount necessary for molding the molded article, and the surplus resin can be continuously supplied into the tank by the circulation device, so that there is an effect that the molding operation can be smoothly and efficiently performed.

[Brief description of drawings]

FIG. 1 is a partially cutaway front perspective view showing a configuration of a stereolithography apparatus according to the present invention.

FIG. 2 is a cross-sectional view showing the configuration of the stereolithography apparatus of FIG.

FIG. 3 is a cross-sectional view showing another embodiment of the schema device.

FIG. 4 is an explanatory view showing a molding step of a cured product layer by the stereolithography apparatus of the present invention.

FIG. 5 is a partial cross-sectional view showing a molded state of a cured product layer by the stereolithography apparatus of the present invention.

FIG. 6 is a sectional view showing an example of a conventional stereolithography method.

FIG. 7 is an explanatory diagram showing a difference in curing profile of a photocurable resin when an ultraviolet laser is used as a light irradiation device and when a semiconductor laser is used.

FIG. 8 is a partially enlarged view of a cured product layer when the stereolithography method of FIG. 6 is performed with an ultraviolet laser.

FIG. 9 is a partially enlarged view of a cured product layer when the stereolithography method of FIG. 6 is performed with a semiconductor laser.

[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: Skimmer device 23: Resin circulation tank 24: Circuit 25: Circulation pump 26: Supply nozzle 27: Drive motor 28: Belt 29: Leveling plate 30: Schematic device 31: Leveling plate 32: Drainage Plate 33: Bracket 34: Supply nozzle

Claims (4)

[Claims] 1. A light irradiation device for curing the photocurable resin, which is movable in horizontal and vertical directions, is provided below a resin molding tank having a bottom surface made of a transparent plate and storing the photocurable resin. , Above the resin modeling tank, in the optical modeling apparatus by the regulated liquid surface method, which comprises a modeling base plate for stacking and fixing the molded article, in the resin modeling tank,
A circulation device for supplying and collecting a resin for uniformly supplying the photocurable resin in an amount corresponding to the layer thickness of the layered model into the modeling tank, and a skimmer device for the resin liquid surface are provided. Stereolithography device. 2. A circulating device for supplying and collecting the resin,
A resin recovery groove provided around the molding tank, a resin circulation tank for storing the recovered resin, a resin in the resin recovery groove is sent to the resin circulation tank, and a resin in the resin circulation tank The stereolithography apparatus according to claim 1, further comprising a circulation pump for sending the resin to the resin recovery groove. 3. The leveling plate, wherein the skimmer device is in contact with the peripheral portion of the modeling tank and is moved from one side to the other side of the modeling tank, and the leveling plate disposed on an outer side surface of the modeling tank. The stereolithography apparatus according to claim 1, comprising a driving device for driving. 4. The skimmer device supplies a drain plate for removing unnecessary resin remaining on the transparent plate after forming the front layer in the forming tank, and a resin for forming the next layer into the forming tank. The stereolithography apparatus according to claim 1, further comprising: a nozzle for smoothing and a leveling plate for smoothing the liquid level of the resin supplied from the nozzle to the same level as the height of the peripheral portion of the modeling tank.