JPH0825487A - Support formation method in stereolithography - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a support forming method in an optical molding method capable of selectively supporting an overhang portion of a molded article and facilitating support removal work after molding. [Configuration] Since a predetermined gap 2a is provided between the modeled article 1 and the support 3 when the unit photo-cured layers 3a, 1a are formed on the XY plane, the upright surface 11 and the inclined surface ( A gap 17 is opened between the support 3 and the slope (not overhanging), and the support 3 is not connected to the model 1. On the other hand, when the angle of the overhang becomes a certain amount or more, the end portion of the unit photo-curable layer 1f of the shaped article rides on the upper part of the unit photo-curable layer 3e of the support which is one layer below. Therefore, the overhanging portion 15 of the modeled article 1 is selectively supported, and the modeled article 1 and the support 3 are not connected at other portions. Therefore, the connecting portion between the modeled article and the support is minimized, which facilitates the support removing work after modeling.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a support for supporting a main body of a modeled article during modeling in a stereolithography method. In particular, since it only contacts the overhanging part of the modeled object, it has the advantage of reliably supporting the part of the modeled object that really needs support and minimizing the work of removing the support after modeling. Regarding the method.

[0002]

2. Description of the Related Art When creating a molded article by a stereolithography method,
There is a technique for performing modeling while simultaneously performing stereolithography on a support that supports the modeled object so that the modeled object does not deform during modeling. As for what kind of support is specifically used, the support is individually designed according to the shape of the modeled object and stereolithography CAD is performed.
There is a method to add to the data (individual design method). However, what is often done is that if an area for forming a support around (or in) the main body of the object is instructed to the dedicated data editing system of the stereolithography apparatus, a thin-walled grid pattern is formed in the area at equal intervals. This is a method of automatically forming the support of (grid method). The lattice method is less troublesome than the individual design method because support design is not required.

[0003]

However, in the lattice method,
Since a support is erected around the modeled object and connected to the modeled object, it is difficult to remove the support from the modeled object after the modeling and care for the surface of the modeled object.

Japanese Unexamined Patent Publication (Kokai) No. 5-301293 proposes a support forming method for solving this problem.
In the method disclosed in Japanese Patent Laid-Open No. 5-301293, when the angle between the surface of the modeled object and the support connected thereto is below a certain degree (the support comes along the surface of the modeled object), the portion of such support is used. The purpose is to improve the above-mentioned problem by taking measures such as not forming (one element of a lattice-shaped thin plate) (not shining light).

However, if the method disclosed in Japanese Unexamined Patent Publication No. 5-301293 is specifically implemented on a dedicated data editing system of a stereolithography apparatus, the amount of calculation of the angle becomes enormous and the support design time is increased. Is a new problem. In addition, returning to the basics of support, what really needs support is the part where the model is overhanging to some extent, and the part where the wall surface of the model is upright does not require support. In most cases. However, there has been no suggestion of support that can selectively support the overhang portion and that is easy to design.

It is an object of the present invention to provide a support forming method in an optical molding method which can selectively support an overhang portion of a molded article and facilitates support removal work after molding.

[0007]

In order to solve the above-mentioned problems, the support forming method in the stereolithography method of the present invention is the same as the stereolithography method for supporting the sculpture when the sculpture is produced by the stereolithography method. A method of forming a support formed by a method;
Axis) and two axes (X axis, Y) on a plane orthogonal to this Z axis
(Axis) in the space defined by the coordinates, the unit photo-curing layers having a certain thickness in the Z-axis direction and a certain shape in the XY plane are formed while being laminated and bonded in the Z-axis direction. A feature is that the unit photocurable layer is formed with a predetermined gap between the modeled article and the support on the XY plane.

[0008]

When a unit photocurable layer is formed on the XY plane, a predetermined gap is provided between the modeled object and the support, so that the modeled object can be used as an upright surface or an inclined surface (a sloped surface that does not overhang). A gap is opened between the support and the support, and the support is not connected to the modeled object. On the other hand, when the angle of the overhang exceeds a certain level, the end portion of the unit light-cured layer of the shaped article comes to rest on the upper portion of the unit light-cured layer of the lower support. That is, although there is a gap between the modeled article and the support on the XY plane, the unit photo-cured layer of the modeled article and the unit photo-cured layer of the support are connected in the Z direction. Therefore, the overhanging portion of the modeled article is selectively supported, and the modeled article and the support are not connected to each other at other portions. Therefore, the connecting portion between the modeled article and the support is minimized, which facilitates the support removing work after modeling. It is needless to say that the method of the present invention is also useful in a stereolithography system that uses plane polar coordinates instead of the above XY coordinates.

[0009]

Embodiments of the present invention will be described below. Figure 1
FIG. 7 is an explanatory diagram of a modeled object and a support modeled by the support forming method in the stereolithography method according to the embodiment of the present invention. (A) is a perspective view, (B) is a BB sectional view in (A), and (C) is an enlarged conceptual view of a portion C in (B).

As shown in the sectional view (B), the molded article 1 shown in FIG. 1 has a cone whose diameter gradually increases upward on the lower cylindrical shaft. It has a shape like this. Around the modeled article 1, supports 3 in the form of an orthogonal lattice are formed. The point of the present invention is
As shown in (B), the upright wall 11 on the molded article 1
The small overhang portion 13 is not in contact with the support 3 and there is a gap 17 between them. On the other hand, the large overhang portion 15 and the support 3 are in contact with each other, and only the same portion 15 is selectively supported.

FIG. 1 (C) shows such a mechanism.
Will be described with reference to. FIG. 1C is C of FIG.
It is an enlarged conceptual diagram of a part. The modeled article 1 is formed by laminating the modeled unit photocurable layers 1a to 1g. The support 3 is formed by laminating support unit photo-curing layers 3a to 3f. Then, a gap (space) 2a exists between each layer, for example, the support unit photo-curing layer 3a and the shaped object unit photo-curing layer 1a. The width of this gap 2a is S (for example, 0.3 mm), and the unit photocurable layer 1
The thickness of a and 3a is t (for example, 0.1 mm).

The support unit photo-curable layer 3a is formed at the same timing (a series of planar exposure timing) as when the model-formed unit photo-curable layer 1a is photo-formed. After that, a photocurable resin having a thickness t is introduced onto the unit photocurable layers 3a and 1a, and the next unit photocurable layers 3b and 1b are molded. Unit photocurable layer 3
A similar gap 2b exists between b and 1b. In this way, the unit photocurable layers are laminated one after another.

Since the degree of overhang on the wall surface of the modeled object 1 becomes higher as it goes up, the modeled unit photocurable layer 1d is reached, and the lower left end of the modeled unit photocurable layer 3c is the lower support unit photocurable layer 3c. It touches the upper right corner. Further, the lower surface of the left end portion of the shaped object unit photo-curable layer 1f is on the support unit photo-cured layer 3e which is one layer below. Therefore, the molded object unit photo-curing layer 1f and the support unit photo-curing layer 3e are contact-connected in the Z direction.

That is, the inclination of the overhang is SIN
^From the time point over ^-1 t / s, the overhang is selectively supported in contact with the support in the Z direction.
Therefore, it is possible to selectively support only the part of the modeled object that really needs to be supported.

FIG. 2 is an explanatory view of an example of a method for constructing shape data for stereolithography the support shown in FIG.
As shown in (A), a method for constructing the shape data of the support on the line a along the Y axis will be described. The thick line 23 on the line a is the primary unit line of the support on the same line. That is, it is a unit line of a line drawn in a lattice pattern in a region including a constant peripheral portion of the shaped product unit photo-curable layer 21. In the conventional support, the actual support shape data is the rest of the support primary unit line 23 after subtracting the portion that overlaps with the modeling unit photocurable layer 21.

In the present embodiment, the following operation is performed in order to open a proper gap between the support and the shaped article. First, two lines c and b separated from the line a by the assumed gap width S in the X direction are drawn in the Y axis direction. And the lines c, b
Shape data of the modeled object above (modeled object unit lines 25, 2
Calculate 7).

Next, as shown in FIG.
Modeling unit lines 31, 25, 27 on the lines a, b, c
On the other hand, an offset corresponding to the gap amount to which the assumed gap width S is added is performed. Then, the total shape data on the line C (model object unit line 27 + cap offset 37, 3
7 ′), the total OR on the Y-axis of the total shape data on the line a and the total shape data on the line b is calculated (each line is superposed on the line a).

Next, from the support primary unit line 23 of (A), the line of superimposition of the unit line of the shaped article and the gap offset on the lines a, b and c obtained by the process of (B) is subtracted. The rest, as shown in FIG. 2 (C),
It is reconstructed as the final support shape data. By doing so, it is possible to construct the support CAD date in which the gap offset in the Y-axis direction is performed in consideration of the interference on the X-axis.

Using the method of the present invention and the conventional method described above, a test for making a model of a mouse cover for operating a personal computer was conducted. FIG. 3 is a diagram showing the shape of a mouse that was test-molded. (A) is a perspective view of the outer surface, and (B) is a bottom view. The mouse cover 41 is thin (about 2 mm)
It has a roof-like shape with dimensions of 100 mm in length, 60 mm in width and 31 mm in height.

Supports 47 are formed on the inside 45 of the mouse cover 41 in the form of a rectangular lattice. At this time, 0.3 mm is given as a parameter of the gap, and the thickness of the lattice is 0.2
mm. For the stereolithography, a stereolithography device SOLIFORM manufactured by Teijin Seiki Co., Ltd. was used. Also, the photocurable resin is S
OMOS3100 was used. Also, the main modeling data specifications are stacking pitch 0.15 mm, laser power 170 m.
W and scan pitch were 0.0508 mm.

After the completion of modeling, the support was removed as post-treatment, cleaning with alcohol and surface finishing were performed. While the post-processing time in the prior art was 2 hours 15 minutes, the post-processing time in this embodiment and examples, 1:00
The time was 5 minutes , and the time required for the post-treatment process could be shortened. In addition, since unnecessary contact with the support is avoided, the surface roughness is 45 compared to that of the conventional technology.
I was able to improve it.

[0022]

As is apparent from the above description, the support forming method in the stereolithography method of the present invention exhibits the following effects. At the time of modeling, when the cross-sectional shape change of continuous sections of the modeled object is small (when the overhang is small), unnecessary contact between the modeled object main body and the support is avoided by the gap existing between the two. The amount of traces of the support remaining on the model body after removing the support from the model body is reduced, and the surface roughness of the model is improved. Since the main body of the modeled object and the support are in contact only in the Z-axis direction, it is easy to separate the support from the main body and perform the surface repair work.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a modeled object and a support modeled by a support forming method according to an embodiment of the present invention.
(A) is a perspective view, (B) is a BB sectional view in (A), and (C) is an enlarged conceptual view of a portion C in (B).

FIG. 2 is an explanatory diagram of an example of a method of constructing shape data for stereolithography the support of FIG.

FIG. 3 is a diagram showing the shape of a mouse that was test-molded.
(A) is a perspective view of the outer surface, and (B) is a bottom view.

[Explanation of reference numerals] 1 model 3 support 11 upright wall 13 small overhang part 15 large overhang part 17 skimmer 1a to g model unit photocurable layer 2a to f gap 3a to f support unit photocurable layer 21 model unit Photocuring layer 23 Support primary unit line 25 Modeling unit line 27 Modeling unit line 31 Modeling unit line 33 Gap offset 35 Gap offset 37 Gap offset 39 Support final unit line 41 Mouse cover 43 Side wall 45 Internal 47 support

Claims (1)

[Claims] 1. A method of forming a support, which is also formed by the stereolithography method, for supporting the molding object when forming the molding object by the stereolithography method; Z axis) and a space defined by coordinates on two axes (X axis, Y axis) on a plane orthogonal to the Z axis and having a thickness in the Z axis direction and XY
A unit photo-curing layer formed to have a certain shape in a plane is laminated and bonded in the Z-axis direction; a unit photo-curing is performed with a predetermined gap between the modeled article and the support on the XY plane. A method of forming a support in a stereolithography method, which comprises forming a layer.