JPH01237122A - Optical shaping method for thick wall section - Google Patents

Abstract

PURPOSE:To prevent a photoset material from generating cracks because of set shrinkage by connecting photoset points in lines by means of moving on-off light flux, arranging adjacently a plurality of lines, directing a large light flux to a beltshaped section and setting the non-set sections between photoset spots. CONSTITUTION:Spot sections irradiated with light flux 14 are photoset to form photoset spots 60 and photoset spot lines 61 are formed by connecting said sections in lines. Then, light fluxes 14 are directed in spots on a center 51 of a section 50 to form a central photoset line 62 by moving the light flux 14 in the right direction while a mask 19 is revolved. A photoset spot line 63 is formed along one side of the section 50 by revolving the mask 19 and scanning the light flux 14. A mask 18 is revolved in a manner that a large hole 18a of the mask 18 is positioned accurately on the light flux moving direction A to the center of the mask to revolve the mask 19 and scan light flux 14. The large light flux 70 is so scanned as to cover the photoset spot lines 61, 62 and 63, and the light is directed to the non-photoset sections between respective photoset spots 60 of the photoset spot lines 61, 62 and 63 and said sections are set.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to an optical modeling method for manufacturing a cured body with a thick cross section of a desired shape by irradiating a photocurable fluid material with light, and particularly relates to an optical modeling method for manufacturing a cured body having a thick cross section of a desired shape. The present invention relates to an optical modeling method that can alleviate the above problems and improve the manufacturing accuracy of cured products.

[Prior art] A light beam is irradiated onto a photocurable fluid material such as a photocurable resin,
The irradiated part is cured, and this cured part is made to continue in the horizontal direction, and a photocurable fluid material is further supplied above it and cured in the same manner, thereby making the cured body continuous in the vertical direction. An optical modeling method for manufacturing a cured body of a desired shape by repeating the process is disclosed in Japanese Patent Application Laid-Open No. 60-2475.
No. 15, No. 62-35966, No. 62-101408, etc. In addition, light is irradiated through a modeling mask having a slit corresponding to the cross section of the cured product in the desired shape to cure it, and then an uncured photocurable fluid material is placed on the cured layer, and this modeling mask is applied. There is also a known optical modeling method in which a cured body of the desired shape is manufactured by replacing the hardened body with one having a slit corresponding to one cross section adjacent in the height direction of the cured body of the desired shape, and repeating the process of irradiating light again. (For example, the above-mentioned Japanese Patent Application Laid-Open No. 62-35966
issue).

In order to create a thick cross-sectional body, a method is known in which scanning is performed by finely and continuously reciprocating the light beam from side to side (FIG. 2 of the above-mentioned Japanese Patent Laid-Open No. 101408/1983).

[Problems to be Solved by the Invention] Photocurable resins shrink when cured, and when producing models using resin, shrinkage causes accuracy problems.
Solving this problem is extremely important in practice. Also,
There was also a risk that cracks would occur in the cured product due to curing shrinkage.

The method of finely reciprocating the light beam from side to side requires a complicated light beam scanning mechanism and is difficult to control.

[Means for Solving the Problems] The present invention provides an optical modeling method having a step of forming a cured layer of a photocurable fluid material corresponding to a cross section of a cured body having a target shape by scanning a light beam. In the curing step, a moving light beam is interrupted to continuously form a row of hardening points, and a plurality of rows of hardening points are arranged adjacent to each other to form a band-shaped part in which the rows of hardening points are gathered. The second step is to irradiate the strip-shaped portion with a main beam of light that is thick enough to cover the strip-shaped portion in the width direction to harden the uncured portion between the hardening points.

[Function] In the present invention, the photocurable fluid material is cured in the following manner to create a three-dimensional object having a desired shape.

(a) In the first step, when the photocurable fluid material is irradiated with intermittent light flux, curing starts at the point where the light is irradiated.

(b) The hardening spreads outward using the hardened portion in (a) as the core.

(C) Subsequently, in the second step, when the main light beam is irradiated, the uncured photocurable fluid material is also cured, and the core portions produced in (a) are connected to each other and integrated.

In this way, in the first step, hardening cores are first generated, but since these cores are extremely numerous and evenly distributed in the hardened product, the shrinkage stress is dispersed. can be achieved. In addition, when curing and shrinkage are progressing around the core, the surrounding area is surrounded by uncured photocurable fluid material, so no shrinkage stress is generated around the core, and the core shrinks. Almost no stress is generated.

And even when this hardening of the core spreads to the surroundings,
As long as there is an uncured photocurable fluid material on the outer periphery, almost no shrinkage stress is generated in the curing area. In this way, according to the method of the present invention, the absolute value of the shrinkage stress itself becomes an extremely small value.

In the present invention, since the cured material serving as the core portion is arranged in a plurality of rows, a thick cross-sectional body can be created.

[Example] FIG. 1 is a block diagram of an apparatus for carrying out the present invention.

FIG. 2.3 is a plan view of the mask 18.19.

A photocurable fluid substance 12 is housed in the container 11, and a lens 15 is installed so as to irradiate a light beam 14 toward the liquid surface 13.
, mirrors 16, 17, a mirror moving device 16a for horizontally scanning the mirror 16, a mask 1\8, 19, a mask rotating device 20, and the like.

A table 21 is installed inside the container 11, and the table 2
1 can be raised and lowered by an elevator 22.

These moving device 16a, rotating device 20, elevator 22
is controlled by computer 23.

The masks 18 and 19 each have large holes 18a at equal radial positions,
19a, and the mask 18 has a small hole 18b.
is drilled.

Note that the mask 18 may be a multi-hole mask with different diameters, but the number of holes is limited to two. Further, the mask 19 may also be a porous mask having one or more large holes.

One mask 18 is a fixed mask, and is arranged coaxially with the rotating shaft 20b of the motor 20a of the rotating device 20. This mask 18 is not rotated by the motor 20a, but is pivoted to the machine box 20c of the rotating device 20 by an appropriate drive device such as a step motor (not shown) so that the installation posture of the mask 18 around the shaft 20b can be changed. ing.

The other mask 19 is fixed to the motor rotating shaft 20b.

In this embodiment, the masks 18 and 19 are arranged so as to be centered on the rotating shaft 20b, but the masks 18 can be adjusted as shown in FIGS. 4, 5, and 11 described below. If possible, it is not necessary to arrange them coaxially, and they may be arranged on separate axes.

The light beam 14 is a light source light beam 24 from a light source (not shown) reflected by the mirror 16.17, and passes through the hole 18a or 18b of the fixed mask 18, and the hole 19a of the rotating mask 19 overlaps with the hole 18a or 18b. Sometimes, it also passes through the hole 19a and reaches the liquid level 13.

In the present invention, a solid object having a desired shape is created by, for example, cutting it into a large number of slices by gradually changing the height in the horizontal direction, and stacking these slices. This allows the thickness of the sliced body to be increased. For this purpose, in the present invention, a hardening point array is formed by intermittent irradiation with the light beam 14,
The method also includes a first step of arranging a plurality of rows of hardening points in parallel.

Therefore, an example of a light flux manipulation method when three curing point arrays are arranged in parallel using the above-mentioned apparatus will be described below.

In this case, first, as shown in FIG.
The mask 18 is set so that it is at a position rotated by a small angle a counterclockwise from the traveling direction A of the light beam 14. Then, while rotating the mask 19, the mirror drive device 16
According to a, a mirror 16, a mask rotation device 20. Masks 18 and 19 are moved 6 times to the right in FIG. 1 as one unit.

As a result, the light beam 14 reflected by the mirror 16 also moves to the right in FIG. The light beam 14 is irradiated onto the liquid surface 13.

Therefore, the portion irradiated with the light beam becomes a point, as shown in FIG. 7, and this point is shifted by a required distance d from the center 51 of the cross section 50 where the object shape is to be formed. The part irradiated with the light beam 14 in the form of a point is hardened to a hardening point 6
o, and by continuing in a row, a hardening point row 61 is formed.

Next, turn the mask 18 clockwise by a small angle a, and
The mask 18 is set so that the light beam 8b is positioned exactly on the light flux traveling direction A with respect to the center of the mask 18, as shown in FIG. Then, while rotating the mask 19, the light beam 14 is directed to the first
Move it 8 times to the right in the figure. Then, as shown in Figure 8,
The light beam 14 is irradiated point by point on the center 51 of the cross section 50 to be formed, and a central hardening point array 62 is formed.

Next, the mask 18 is further turned clockwise by a small angle a, and the mask 18 is moved so that the hole 18b is shifted from the traveling direction A by a small angle a clockwise with respect to the center of the mask 18.
Set 8. In this state, the rotation of the mask 19 and the luminous flux 1
4, a hardening point array 63 is formed along one side of the cross section 50 to be formed as shown in FIG.

Thereafter, as shown in FIG. 11, the mask 18 is rotated so that the large hole 18a of the mask 18 is positioned precisely on the light flux traveling direction A with respect to the center of the mask, and the mask 19 is rotated and the light flux 1
4 scans are performed. Or the large hole 19a of the mask 19
is aligned with the large hole 18a of the mask 18 and fixed, and scanning with the light beam 14 is performed without rotating the mask 19. Then, the main light beam 70 is scanned so as to cover the hardening point arrays 61, 62, 63, and the uncured portions between the hardening points 60 of the hardening point arrays 61, 62, 63 are also irradiated with light and hardened.

In this way, one thick cross-section of the target shape is formed.

Next, a method of creating a three-dimensional object by stacking each cross section (circular slice) will be explained.

First, the table 21 is positioned slightly below the liquid level 13, and the light beam 14 is scanned along the horizontal cross section of the target object. This scanning is performed by a computer-controlled mirror 8 movement device 16a.

By irradiating the entire horizontal cross section of the target shape (in this case, the part corresponding to the bottom surface) with light, a plurality of rows of hardening points 61, 62, 63 are formed as described above, and the unhardened portion is cured by the main beam. After irradiation, the table 21 is lowered slightly to allow the uncured photocurable fluid material to flow onto the cured material 26, and then the same light irradiation as above is performed. By repeating this procedure, a cured product having the desired shape can be obtained.

In this way, the curing points 60 are uniformly distributed and curing starts, so even in the case of a thick-walled cross-section, the shrinkage stress generated during curing becomes small, as explained in the section of the above-mentioned effect. It becomes uniformly dispersed throughout the cured product.

In the above embodiment, the table 21 is gradually lowered, but conversely, by adding more photocurable fluid material, the liquid level increases.
3 may be gradually increased. Further, the optical system may employ an optical fiber. Furthermore, the optical system may be kept stationary and the light beam 14 may be moved relative to the liquid surface 13 by moving the container 11.

In the above embodiment, the irradiation light is irradiated onto the liquid surface from above, but in the present invention, at least the required portions of the container 11 are made into transparent parts, and the light is irradiated from the bottom and side surfaces of the container. You can also do it. In this case, the table may be gradually pulled upward or driven sideways during the molding process.

In the present invention, various substances that are cured by light irradiation can be used as the photocurable fluid substance, such as modified polyurethane methacrylate, oligoester acrylate, urethane acrylate, epoxy acrylate, photosensitive polyimide, and amino alkyd. Can be done.

As the light, various types of light such as visible light and ultraviolet light can be used depending on the photocurable material used. Although the light may be ordinary light, using laser light has the advantages of increasing the energy level, shortening the modeling time, and improving the modeling accuracy by utilizing good light focusing. can.

[Effects of the Invention] As described above, according to the present invention, it is possible to reduce the shrinkage stress generated in the cured body in the optical modeling method and to uniformly disperse the shrinkage stress throughout the cured body. Therefore, even if the cross section is thick, a highly accurate model without cracks and with almost no dimensional errors due to shrinkage can be manufactured.

Furthermore, the device configuration is simple and its control is easy.

[Brief explanation of the drawing]

Figure 1 is a longitudinal cross-sectional view of the device employed in the example method;
Figures 3 and 3 are explanatory diagrams of the structure of the mask, Figures 4 and 5,
6 and 11 are explanatory diagrams of the posture of the mask 18, and FIGS. 7, 8, 9, and 10 are explanatory diagrams of the light irradiation process. 12... Photocurable fluid substance, 14... Luminous flux, 16... Mirror, 18
...Porous mask, 21...Table, 22...Elevator, 5o...Cross section of target shaped body, 60...Curing point, 61.62.63...Curing point array. Agent Patent Attorney Tsuyoshi Shigeno Figure 1 Figure 4 Figure 5 Figure 6 Figure 7 Figure 11

Claims (1)

[Claims] (1) In an optical modeling method that includes a step of irradiating a photocurable fluid material with a moving light beam so as to draw a cross section of a desired shape, and curing the portion irradiated with the light beam, the curing step includes: moving. a first step of forming a continuous row of hardening points by intermittent light flux therein, and forming a band-shaped part in which the hardening point rows are assembled by adjoining a plurality of hardening point rows; a second step of irradiating the strip-shaped portion with a main beam having a thickness that covers the strip-shaped portion in the width direction to harden the uncured portion between the hardening points. Optical modeling.