JP2002347125A - Optically molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optically molded article which is reduced in fluctuations of strength depending on portion as the optically molded article with its thickness part being made hollow, wherein a high shape accuracy is obtained in the optical molding without any collapse in shape, and which can be applied as a suitable lost pattern for casting. SOLUTION: Respective layers obtained by parallel slicing a three-dimensional model of a design product into compound high density layers are laminately formed as a cured layers of photocurable resin in the optically molded article M. The thickness part of the design product is formed hollow, the hollow inside 1 is sectioned by a reinforcing wall 2 into a honeycomb shape seen from the direction of the optical molding, the sectioned small spaces 10 are communicated with each other through lacking parts 3 of the reinforcing walls 2, making the whole of the hollow inside 1 of the thickness part be in a communication condition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optically molded product obtained by laminating layers obtained by parallel slicing a three-dimensional model as a cured layer of a photocurable resin by optical molding, and is particularly suitable as a burn-out prototype for casting. It relates to a stereolithography.

[0002]

2. Description of the Related Art In recent years, automobiles, aircraft, buildings, home appliances,
2. Description of the Related Art Techniques for designing and designing products and parts in various industrial fields such as toys and daily necessities on computers such as CAD, CAM, and CAE are widely used. And, as the latest means for producing a real model that embodies a three-dimensional model designed on such a computer, the design model was sliced in parallel into a number of layers of several tens to hundreds of μm thick on a computer. A stereolithography method that creates data of each cross-sectional pattern at the time and directly obtains a three-dimensional resin model from this data has appeared.

In this stereolithography method, data of the cross-sectional pattern is input to a control device of the stereolithography apparatus, and a lift pedestal placed in a molding tank containing a solution of a photocurable resin such as an ultraviolet-curable resin is used as a liquid. The surface is set to a depth corresponding to the thickness of the sliced layer, and a laser beam emitted from a laser head equipped with an XY scanner is irradiated on the liquid surface along the cross-sectional pattern of the lowermost layer, whereby Form a cured resin layer in a pattern shape, then lower the elevating pedestal by the thickness of the one layer, spread the solution over the cured resin layer with a recoater, and similarly irradiate a laser beam to cross-sectional pattern of the second layer By forming a cured resin layer corresponding to the above, and then lowering the elevating pedestal one by one in order in the same manner and irradiating a laser beam, finally the parallel slices Cured resin layer corresponding to all of the cross-sectional pattern making resin model integrally laminated.

It has been proposed that such a resin model by stereolithography is used not only for confirming the form of a design model, but also as a prototype to be used as a prototype for burning out in addition to being subjected to various characteristic tests (see, for example). For example, Patent No. 2930
354, JP-A-2000-141498).

[0005] In the casting using a burnt-out mold, a mold of a cast product is made of resin, the mold is buried in a mold material, and the mold is heated to burn off the mold to form a mold space in the mold material. After the mold is formed, the molten metal is poured into the mold space, or the mold is buried in the mold material while the mold is embedded in the mold material. It is to be replaced with molten metal. However, according to stereolithography, even a burnt-out prototype having a complicated structure can be easily manufactured in a short time, and the hollow portion of the flesh reduces the amount of resin, thereby reducing the amount of combustion gas generated due to burnout. This has the advantage that the mold can be prevented from cracking due to this gas pressure.

[0006]

However, in the case of a hollow burnt-out mold manufactured by stereolithography, the strength of the mold itself is insufficient. There is a drawback that the shape accuracy is easily reduced. Therefore, in the past, reinforcing walls are provided at important points inside the hollow, but the variation in strength due to the site becomes large, and since the hollow inside is partitioned by the reinforcing walls, the optical molding is used. During the molding process, a plurality of closed areas surrounded by a cured resin layer are formed on the liquid surface of the photo-curable resin solution, and a difference in the liquid surface level occurs between these closed areas due to surface tension, etc., and reinforcement is formed. There was a problem that the shape of the wall was easily caused.

[0007] In view of the above-mentioned circumstances, the present invention provides a stereolithographic object having a hollow meat portion, which has a small variation in strength depending on the part, and which can obtain a high shape precision without collapse in stereolithography. It is an object of the present invention to provide a burnable prototype that can be suitably applied.

[0008]

In order to achieve the above-mentioned object, a stereolithographic object according to claim 1 of the present invention has a multi-layered three-dimensional model of a designed article as shown by reference numerals in the drawings. Is an optical molded article M in which each layer when sliced in parallel is laminated as a cured layer of a photo-curable resin, wherein the meat portion of the designed article is formed hollow, and the hollow interior 1 is a reinforcing wall 2
Are divided in a honeycomb shape when viewed from the optical molding direction, and the divided small spaces 10 communicate with each other by the lacking portions 3 of the reinforcing wall 2 and the hollow portion of the meat portion is formed through these lacking portions 3. It is characterized in that the entire interior 1 is in communication.

In the stereolithographic object M having the above structure, since the hollow interior 1 is partitioned in a honeycomb shape by the reinforcing wall 2, the entire hollow meat portion is uniformly reinforced from the inside, and
When embedded in a mold material as a burnt-out prototype for casting, local deformation is unlikely to occur, so that a mold space with good shape accuracy and dimensional accuracy can be formed. Further, in the manufacture of the optical molding M by optical molding, the small spaces 10 divided in a honeycomb shape by the reinforcing wall 2 communicate with each other by the lacking portions 3 of the reinforcing wall 2. Are in communication with each other, so that there is no difference in hydraulic pressure between the small spaces 10... Throughout the entire process of optical molding, and there is no difference in the level of the liquid surface due to surface tension or the like. .

Thus, the hollow interior 1 is partitioned in a honeycomb shape by the reinforcing wall 2, and the partitioned small spaces 10 are communicated with each other by the lacking portions 3 of the reinforcing wall 2, and these lacking portions are connected to each other. There is no particular limitation on the configuration for bringing the entire hollow interior 1 of the meat portion into a communication state through the intermediary, but when the reinforcing wall 2 forms a hexagonal honeycomb wall, the configuration according to claims 2 to 4 Is a preferred specific example.

That is, in the configuration of the second aspect, the first cross-sectional portion 11 lacking the one-way wall portion 2b of the three-directional wall portions 2a, 2b, 2c constituting the hexagon, The second cross-sectional portion 12 consisting of only the one-way wall portion 2b missing in the cross-sectional portion 11 is alternately and repeatedly arranged along the stereolithography direction. Further, in the configuration of claim 2, the three-directional walls 2a, 2b, 2 constituting the hexagon.
c first section 13 lacking one-way wall 2c
And the one-way wall portion 2 which is not missing in the first section 13
c and the third cross-section 15, which lacks the one-way wall 2 a that is not absent in the first and second cross-sections 13, 14, are sequentially formed along the stereolithography direction. They are arranged repeatedly. Further, in the configuration of the third aspect, the first cross-section 16 in which the small spaces 10 are separated from each other by the reinforcing wall 2 and the three-directional wall portions 2a, 2b, and 2c forming the hexagon are formed in two directions. The wall sections or the second cross-section sections 17a to 17d lacking the wall sections in all three directions are alternately and repeatedly arranged along the stereolithography direction.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of an optically molded object according to the present invention will be specifically described below with reference to the drawings. FIG. 1 shows an example of a cast product C obtained by using the stereolithographic product of the present invention as a burnout prototype. This casting C is a substantially rectangular thick plate curved so as to bulge to one surface side, and has a U-shaped notch D at the center of one side edge thereof.

The stereolithography M of the first embodiment shown in FIG. 2 is obtained by stereolithography from bottom to top in an upright posture with the cutout D side down, using the casting C of FIG. 1 as a design model. It is entirely hollow. The hollow interior 1 of the stereolithography object M is partitioned into a hexagonal honeycomb shape when viewed from the stereolithography direction, that is, the vertical direction, by the reinforcing wall 2 integrated with the surface wall portion 4 corresponding to the entire surface of the casting C. 3A shown in FIG. 3A and FIG.
The second cross-sections 12 shown in (b) are alternately arranged along the stereolithography direction.

Thus, in the first section 11, the three-directional walls 2a, 2 of the reinforcing wall 2 forming the hexagon of the honeycomb are provided.
Among the b and 2c, the two-way walls 2a and 2b are connected in a zigzag manner to be continuous with the surface wall 4, but the remaining one-way wall 2c is missing. The hexagonal small spaces 10 communicate with each other only in the thickness direction of the modeled object. On the other hand, in the second section 12, only the one-way wall 2c that was missing in the first section 11 is present, and the walls 2a and 2b are missing.
, All of the hexagonal small spaces 10 communicate with each other. Accordingly, the entire hollow interior 1 of the optical molding M is also in communication. Each of the walls 2c of the second section 12 is integrated with the bent portions of the walls 2a and 2b in the upper and lower first sections 11 at the left and right ends of the upper and lower edges.

In order to manufacture such a stereolithographic object M, when a three-dimensional model is created on a computer, the first cross section 11.. Designed as a structure in which and are alternately arranged, this design model is created on a computer to create cross-sectional pattern data that is sliced in parallel into multiple layers, and this data is input to the controller of the stereolithography machine, and the data is processed according to a standard method. What is necessary is just to perform stereolithography by automatic operation. The stereolithography operation is shown in FIG.

That is, the upper surface position of the elevating pedestal 5 in the molding tank is set to a depth corresponding to the thickness of the sliced one from the liquid surface 6a of the solution 6 of the photocurable resin such as the ultraviolet curable resin, The liquid surface 6a is irradiated with a laser beam L along the lowermost layer cross-sectional pattern to form a cured resin layer having the cross-sectional pattern shape, and then the lifting pedestal 5 is lowered by the thickness of the one layer to form a recoater (shown in the figure). The solution 6 is spread over the previously formed cured resin layer in (omitted), and similarly irradiated with a laser beam L to form a cured resin layer,
Thereafter, similarly, by sequentially lowering the elevating pedestal 5 by one layer and irradiating the laser beam L, a resin model M in which a cured resin layer is integrally laminated as shown by a virtual line in FIG. . In the drawing, a support section 7 on the lower surface side for facilitating removal of the optical molded article M from the elevating pedestal 5 and liquid drain holes 8 on both sides at the lower end for draining the liquid entering the hollow interior 1. , 8 are provided in advance in the design stage.

In this optically shaped object M, the hollow interior 1 is partitioned into a hexagonal honeycomb by the reinforcing wall 2. For example, during the shaping of the second section 12 shown in FIG. The entire hollow interior 1 is in horizontal communication with each other by the parts 3. Since the small spaces 10 divided by the reinforcing wall 2 have the same liquid pressure, the liquid level between these small spaces 10 is equal. Of the wall 2
c ... is precisely formed without collapse. Also, during the formation of the first cross-section 11, the hollow interior 1 is fractionated by a zigzag series of the walls 2a, 2b in a horizontal plane.
Due to the flow of the liquid in the second section 12 immediately below, there is no difference in the level of the liquid surface between the divided areas, and thus the wall 2
Thus, a and 2b can be precisely formed without shape collapse. In addition, 9 in FIG. 5 indicates a modeling tank.

The hollow interior 1 of the stereolithographic object M of the first embodiment.
Is a first section 1 where the walls 2a and 2b of the reinforcing wall 2 are present.
1 and the second section 12 having only the wall portion 2c are alternately arranged along the stereolithography direction. However, the small space in the stereolithography process is formed by the cut-out portions 3 of the reinforcing wall 2. 10 ...
Various configurations are possible for preventing a difference in liquid level between the two. For example, as shown in FIG. 6A, the first cross-sectional portion 13 in which only the wall portions 2a and 2c of the reinforcing wall 2 exists, and the second cross-sectional portion in which only the wall portions 2a and 2b exist as shown in FIG. A configuration in which the two cross-sectional portions 14 and the third cross-sectional portion 15 having only the wall portions 2b and 2c as shown in (c) are sequentially and repeatedly arranged along the stereolithography direction (second embodiment). However, since the three cross-sections 13 to 15 combine to form a communication state as a whole, the divided small spaces 10 have the same liquid pressure and do not generate a difference in liquid level.

Further, as shown in FIG. 6 (d), the first section 16 in which the small spaces 10 are completely separated from each other by all the walls 2a, 2c, 2c, and FIG. (G) A configuration in which the second cross-sections 17a to 17c having only one direction wall of the walls 2a to 2c as shown in (g) are sequentially and repeatedly arranged along the stereolithography direction (third embodiment) For example, even when the first cross-section 13 is formed, the small spaces 10 that are separated from each other have the same hydraulic pressure due to the overall communication state of the second cross-sections 17a to 17d, and the liquid level is higher or lower. No difference. Further, as in the stereolithographic object M of the fourth embodiment shown in FIG. 7, the first cross section 16 in which the small spaces 10 are completely separated from each other by all the walls 2a, 2c, 2c, Walls 2a, 2c,
2c, that is, the second cross-sectional portion 17d where the reinforcing wall 2 does not exist is also sequentially and repeatedly arranged along the stereolithography direction.
Again, due to the overall communication state at the second section 17d,
There is no difference in the liquid level between the small spaces 10 when the first section 13 is formed.

Thus, even if such a stereolithographic object M has a recess 3 in the reinforcing wall 2, since the hollow interior 1 has a uniform honeycomb structure as a whole, it is hollow and lightweight. Despite being high in pressure resistance and rigidity, and because there is no variation in strength as a whole, local deformation is unlikely to occur when embedded in a mold material as a burnt-out prototype for casting, Thus, a mold space having good shape accuracy and dimensional accuracy can be formed. In addition, since the reinforcing wall 2 has a high strength even if it is thin due to the honeycomb structure, the thin reinforcing wall 2 reduces the amount of resin, reduces the amount of combustion gas at the time of burning, and reduces cracks in the mold due to gas pressure. It is possible to make damage less likely to occur.

In order to perform casting using the burnt-out prototype made of such a stereolithographic object M, for example, as shown in FIG. The resin component 22 and the wax component of the sprue 21 and the feeder 22 are burned and vaporized by adhering the whole 22 and embedding the whole in the mold material 20 and heating in this embedding state. As a result, the mold material 20 is hardened, and a mold space 23 having the same shape as the burned-out optically shaped object M is formed therein, as shown in FIG. A mold communicating with 22 passages is obtained. Thus, a casting C is obtained by pouring a molten metal such as an aluminum alloy into the mold space 23 from the gate 21 of the mold and cooling and solidifying the molten metal.

In the above-described embodiment, a relatively simple form of the optically formed object is illustrated so as to be easily understood by the drawings. However, there is no limitation on the form of the optically formed object which is an object of the present invention. The more complicated the configuration, the greater the application effects of the present invention. Further, the optical molded article of the present invention is particularly suitable as a burn-out prototype for casting, but is also lightweight, high-strength, and precise optical molded article provided for other uses such as simple shape confirmation. Being able to shape is a great advantage.

[0023]

According to the first aspect of the present invention, an optically formed object having a hollow body portion has a high pressure resistance and rigidity, a small variation in strength depending on a portion, and an optically formed object. Thus, the present invention can provide a high shape accuracy without shape collapse, and can be suitably applied especially as a burnt-out prototype for casting.

According to the second to fourth aspects of the present invention, there is provided, as the above-mentioned stereolithography object, a stereolithography product which can be stereolithographically formed with high shape precision without breaking down.

[Brief description of the drawings]

FIG. 1 is a perspective view of a casting as a design model of an optical molded article according to one embodiment of the present invention.

FIG. 2 is a vertical sectional front view of the optically formed object according to the first embodiment of the present invention.

3A and 3B show a cross-sectional structure of the stereolithographic object, wherein FIG. 3A is a cross-sectional view taken along the line II in FIG. 2, and FIG.

FIG. 4 is a front view of a main part showing a stereolithography operation of the stereolithography object.

FIG. 5 is a plan view showing a stereolithography state of a first cross section of the stereolithography part.

FIG. 6 shows a cross-sectional configuration of a stereolithography according to the present invention;
(A) is a first section in the second embodiment, (B) is a second section, (C) is a third section, and (D) is a first section in the third embodiment. (E) to (g) are cross-sectional views respectively showing the second section.

FIG. 7 is a longitudinal sectional side view of an optical molded article according to a fourth embodiment of the present invention.

8A and 8B show a casting method using a burn-off mold made of a stereolithographic product of the present invention, wherein FIG. 8A is a longitudinal sectional view showing a state where the burn-off mold is embedded in a mold material, and FIG. Is a vertical cross-sectional view of a mold obtained by burning off the mold, and FIG. 3C is a vertical cross-sectional view of a state in which a molten metal is poured into the mold.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hollow interior 2 Reinforcement wall 2a-2c Wall part 3 Missing part 4 Surface wall part 6 Photocurable resin solution 10 Small space 11,13,16 First cross-section part 12,14 Second cross-section part 15 Third cross-section part 17a- 17d 2nd section C casting M stereolithography L laser beam

Claims (4)

[Claims] 1. A three-dimensional model of a design article, which is obtained by slicing a three-dimensional model in parallel into a plurality of layers, wherein each of the layers is formed by lamination as a cured layer of a photocurable resin. The hollow interior is partitioned by a reinforcing wall into a honeycomb shape as viewed from the stereolithography direction, and the partitioned small spaces communicate with each other through a missing portion of the reinforcing wall, and the meat is formed through the missing portion. A stereolithographic object characterized in that the entire hollow interior of the part is in communication. 2. A first cross-section in which the reinforcing wall forms a hexagonal honeycomb wall body and one of three-way walls constituting the hexagon lacks a wall in one direction, and a first cross-section thereof. The stereolithographic object according to claim 1, wherein the second cross-sectional portion consisting of only the one-way wall portion missing in the portion is alternately and repeatedly arranged along the stereolithography direction. 3. A first cross-section in which the reinforcing wall forms a hexagonal honeycomb wall body and lacks a one-way wall among three-way walls constituting the hexagon, and a first cross-section thereof. The second cross-section without the one-way wall not missing in the part and the third cross-section without the one-way wall not missing in the first and second cross-sections along the stereolithography direction The stereolithographic object according to claim 1, wherein the stereolithographic object is arranged repeatedly and sequentially. 4. The reinforcing wall forms a hexagonal honeycomb wall body, and the reinforcing wall forms a first cross-sectional portion in which the small spaces are isolated from each other, and two of the three-directional wall portions forming the hexagon.
The stereolithography object according to claim 1, wherein a wall portion in one direction or a second cross-section portion lacking a wall portion in all three directions is alternately and repeatedly arranged along the stereolithography direction.