JP2001009920A - Support forming method in photo fabrication method and designing apparatus therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically form a support at a necessary part so as to match the same with the shape of a solid model by dividing the solid model in a laminar state to form the outer diameter data of each of the divided layers and setting a part where the adjacent layers are separated from the lower layer by a constant distance or more to a support forming region and forming the support at the lower part thereof. SOLUTION: The data of a solid model is devided into layers constant in thickness in parallel to a horizontal surface to form the outer shape data of the respective layers and the distance between the outer peripheral parts of two adjacent layers is measured and a part where the outer peripheral part of the upper layer is separated from that of the lower layer by a constant distance or more is set as a support forming region P. Support forming parts Q1, Q2 are set on the outer peripheral part of the support forming region P and support forming parts Q3 are set to parts, which are present within the support forming region P at a predetermined interval or more, at every predetermined interval and supports are formed at the positions of the support forming parts Q1-Q3 of the lower layer thereof. By this constitution, the supports of the solid model can be formed at accurate positions in a full-automatic manner.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a support in a stereolithography method and a design apparatus using the method. More specifically, when the support is not densely formed at a very small interval and the three-dimensional body is sequentially laminated to produce a three-dimensional model, the end of the thin-layer body may be dropped, The present invention relates to a method of forming a support in a stereolithography method capable of automatically forming a support at a necessary place so that a separation part does not move, and a design apparatus using the same.

[0002]

2. Description of the Related Art Due to recent demands for shortening the product development period and diversifying product designs, a liquid photocurable resin is irradiated with light such as an ultraviolet laser beam, and the cured resin layers are sequentially laminated. A so-called stereolithography (STL) method for producing a three-dimensional resin model by using the method described above is used.

In order to produce a three-dimensional model by stereolithography, different model examples are shown in FIGS. 5A and 5B by a three-dimensional model diagram and a side view, respectively.
First, the three-dimensional data of the three-dimensional model 30 is sliced in the horizontal direction, and each layer is stored as contour data of a thin layer having a thickness of, for example, about 100 to 200 μm. In FIG. 5B, the cross section is shown by a thin horizontal line. Then, as will be described later, the three-dimensional model 30 is produced by sequentially curing only the respective layered portions of the liquid resin from the lower layer.

[0006] However, the hanging portion 30 a distant from the bottom surface of the three-dimensional model 30 (the surface of the modeling table 23).
In FIG. 5B, there is no connection with the table 23, and even if the layer is hardened immediately, it becomes a floating island and floats in the liquid and moves. When the distance from the main body increases, the protruding portion (overhang portion) 30b falls down due to its own weight. for that reason,
As shown in FIG. 5 (c), a support 40 that supports the three-dimensional model is formed in a part that is not related to the three-dimensional model, and the support 40 is also hardened for each layer and manufactured.

FIGS. 6A to 6C show an actual manufacturing method.
As shown in the manufacturing process, a table 23 is set on the surface side of a container 21 filled with a photocurable resin 22, and a laser light source is provided on the table 23 at a portion corresponding to the first layer 31 of the three-dimensional model. 25, the ultraviolet laser light 2
Then, the table 23 is lowered by the thickness of one layer to make the surface a liquid resin layer, the second layer 32 of the three-dimensional model is cured, and this is sequentially repeated. On this occasion,
The support 40 described above is also formed sequentially with the first layer 41 and the second layer 42.

[0006] The curing by the ultraviolet laser beam cures the irradiated portion by irradiating a laser beam. FIG. 7A shows the shape of the cured portion X when the layer 34 is cured by the laser beam irradiation. As shown in the figure, the laser beam is hardened along the wedge shape of about 80 μmφ of the arriving laser beam, and is sequentially hardened at a necessary place by scanning with a laser beam. In this case, as shown in FIG. 7A, for example, when each layer has a thickness of about 100 μm, the reaching depth of the laser beam is set to about 150 μm, and the laser beam is irradiated to the middle of the lower layer 33. By doing, lower layer 3
3 and wedge-shaped and hardened, and both layers 33 and 34 are hardened.
The space adheres and cures.

After curing to the uppermost layer as shown in FIG. 6 (b), as shown in FIG. 6 (c), the table 23 is pulled up from the liquid photo-curable resin 22 and washed. After that, the support 40 is removed, as shown in FIG.
A three-dimensional model 30 as shown in FIG.

As described above, when a three-dimensional model is manufactured by stereolithography, if the position of the support 40 is not provided at an appropriate place, the main body may be tilted during the manufacturing,
As shown in (b), if the end of the lower layer 33 hangs down without support, the laser beam does not reach the lower layer 33 when the upper layer 34 is cured, and the adhesion between the two layers is insufficient, and the separation between the two layers may occur. As a result, it is impossible to produce a three-dimensional model having an accurate shape. Therefore, the place where the support is formed is very important in the stereolithography. However, this support does not exist as three-dimensional model data, and data forming the support must be added to the three-dimensional model data.

As a conventional method of automatically forming a support, for example, a method of forming a support in a grid pattern at regular intervals within the outermost shape of an image projected on the bottom surface of a three-dimensional model is used. For example, Japanese Unexamined Patent Publication No. Hei 5-301293 discloses a method of forming a support for preventing a model from overturning. In this case, too, a method of forming a support in a specific area in a certain area around a projected image is used. It has been disclosed.

[0010]

As described above, if supports are formed at regular intervals based on the external shape on which the three-dimensional model is projected, complicated shapes that do not appear in the external shape of the projected image cannot be considered. For example, as shown in FIG. 7 (c), even if the support 40 can be formed at the outermost end of the projected view, the support is shifted from the position of the hanging portion 30a or the end of the protruding portion 30b. 40 may be formed. Then, the hanging portion 30a becomes a floating island and moves and cannot be formed, or the end of the protruding portion 30b hangs down as shown by a broken line in FIG. There is a problem that it becomes impossible to form the laminated body that has been made. In this case, in addition to simply providing the support forming portions at equal intervals, there may be a case where a stepped portion is recognized when viewed from the back surface of the three-dimensional model, and provided at the end of the stepped portion. However, a continuously changing portion such as an inclined surface cannot be recognized.

In order to eliminate such a problem, it is necessary to increase the number of supports and to form the supports at a high density, for example, at an interval of about 2 mm even when an interval of about 5 mm is preferable. However, when the number of supports is increased, it is necessary to remove the supports when the hardening of each layer is completed and the three-dimensional model is finished, but it is difficult to remove the supports, and when the supports are dense, the support is removed. In this case, there is a problem that the main body is easily damaged. For this reason, under the current circumstances, after the support is automatically formed roughly at equal intervals, it is necessary for the human to manually add the support to the part deemed necessary while viewing the three-dimensional model. And there is a problem that the cost is greatly increased. This problem becomes more serious as the shape of the three-dimensional model becomes more complicated, and the manual operation becomes more complicated.

The present invention has been made to solve such a problem. When a three-dimensional model is formed by stereolithography, support is automatically provided at a necessary portion according to the shape of the three-dimensional model. It is an object of the present invention to provide a support forming method that can be formed.

Another object of the present invention is to provide a three-dimensional model by stereolithography which can automatically create a three-dimensional model and support data for each layer by inputting three-dimensional data of the three-dimensional model to a computer. It is to provide a design device.

[0014]

According to the present invention, there is provided a method for forming a support in a stereolithography method, comprising the steps of: (a) dividing data of a three-dimensional model into layers with a constant thickness in parallel with a horizontal plane to generate data of the outer shape of each layer; (B) measuring the distance between the outer peripheries of two adjacent layers of each of the divided layers, and supporting a portion where the outer perimeter of the upper layer of the adjacent two layers is at least a certain distance from the outer perimeter of the lower layer; (C) an outer peripheral portion of the support forming region and a support forming portion set at a predetermined interval between the outer peripheral portion and the outer peripheral portion of the lower layer; and (d) the support forming portion is set. A support is formed at a position of the layer and the support forming portion below the layer.

Here, the horizontal plane means a horizontal plane of the liquid resin in a state where a three-dimensional model is manufactured in the liquid resin, and has nothing to do with a state in which a three-dimensional model as a product is placed. The constant distance is different depending on the strength of the resin used, the thickness of each layer to be divided, and the like, but is a distance such that the layer protruding in an eaves-like shape does not bend by its own weight, preferably 1 to 3
mm, for example, about 1.5 mm. The predetermined interval is determined by the number of supports that can support the weight of the three-dimensional model, and varies depending on the shape and the like.
It is about 20 mm, preferably about 3 to 10 mm, and more preferably about 4 to 6 mm.

By using this method, even if a three-dimensional model having a complicated external shape that does not appear in the projection view is compared between the divided layers, all shape changes can be recognized, and The support can always be formed where necessary, such as at the end of the part. Moreover, since this method is performed using contour data (xy coordinates of the outer shape of each layer) divided into each layer required in the stereolithography method, it is only necessary to add the calculation between layers without increasing the number of complicated steps. It can be carried out.

When there is a corner at the outer peripheral portion of the support forming region, the support forming portion is preferentially set at the corner, and the support forming portion is further provided at every predetermined interval between the corners. The setting is preferable because the support is formed at the end of the protrusion. Here, the corner portion means a portion where the outer shape changes discontinuously or the direction largely changes via a small arc.

The upper layer has a portion separated in a plane,
When the separated portion is outside the outer peripheral portion of the lower layer, the support forming portion is further set in the separated portion, so that the support is always formed in the hanging portion regardless of the distance from the outer peripheral portion of the lower layer. Therefore, the hardened layer does not float in the liquid resin like a floating island and is stabilized.

When the upper layer is continuous in a plane but has a bent portion, measuring the predetermined distance and the predetermined interval along the path of the bent portion is performed by measuring a straight line from the outer peripheral portion of the lower layer. Even if the distance is not so large, it is preferable that the support can be surely formed when the route is large.

In addition to the change in shape between the adjacent layers, the addition or deletion of the set support forming portion due to the cumulative change of a plurality of continuous layers corrects the support position while grasping a certain overall picture. It is preferable because it can be performed.

When the distance of the outer peripheral portion between the upper layer and the lower layer is less than a certain distance, but the distance is accumulated toward the upper layer, the support forming portion is provided on the outer peripheral portion for each accumulated layer. For example, in the case of a shape like an inverted pyramid, there is not much difference in the distance of the outer peripheral portion between adjacent layers, and even if the accumulated upper layer becomes larger than the lower layer before accumulation and becomes unstable, , Can automatically add support along the way. In this case, the cumulative distance may be measured and added when the distance reaches a constant value, or may be added for each fixed number of layers.

The support design apparatus in the stereolithography method according to the present invention includes means for slicing the three-dimensional data of the three-dimensional model in the horizontal direction to form two-dimensional data of the outer shape of each layer, Means for measuring the distance between the outer peripheral portions, means for specifying a region sandwiched between the outer peripheral portion of the upper layer and the outer peripheral portion of the lower layer as the support formation region when the distance is equal to or more than a predetermined value, and the outer periphery of the support formation region Means for setting a support forming portion at a predetermined interval between the portion and the outer peripheral portion and the outer peripheral portion of the lower layer, and a support at a position of the layer where the support forming portion is set and the support forming portion below the layer. Means.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, referring to the drawings, a support forming method in a stereolithography method according to the present invention and a support design apparatus using the same will be described with reference to a flowchart shown in FIG.

(A) First, the data of the three-dimensional model is divided (sliced) into layers at a certain thickness in parallel with the horizontal plane to create data (contour line shape data) of the outer shape of each layer (S).
1). This division into layers is performed by slicing the three-dimensional model to a thickness of about 100 to 200 μm in parallel with the horizontal plane in the same manner as in the related art. Thereby, the outer shape data of each layer is obtained as xy coordinates.

(B) Next, the distance between the outer peripheral portions of two adjacent layers of each of the divided layers is measured (S2), and the outer peripheral portions of the upper layers of the two adjacent layers are separated from the outer peripheral portions of the lower layers. A portion separated by a certain distance or more is defined as a support formation region P (S
3). For example, as shown in FIGS. 2A and 2B, the lower layer 35 and the upper layer 36 are viewed from below, and the distance A (A1 to A4) between the outer layers of the lower layer 35 and the upper layer 36 is set over the entire circumference. Measure evenly or at regular intervals. This measurement can be calculated by, for example, the xy coordinates of the outer shape of each layer described above.

An area where the distance A is equal to or more than a predetermined distance, for example, 1.5 mm or more is defined as a support formation area P (shaded area). This constant distance is set to such a value that the free end does not hang down by its own weight,
Depending on the characteristics of the resin, the thickness of each layer, etc., an epoxy acrylate resin, for example, SCR701 manufactured by Demec Co., Ltd. is used as the resin, and the thickness of each layer is 100 to
In the case of about 200 μm, it is set to about 1.5 mm as described above. In the example shown in FIG.
Is a distance of about 1.5 to 5 mm, and A3 to A4 are 5 to 10
This is an example of a distance of about mm. Therefore, all the portions P protruding from the lower layer 35 are formed as support forming regions P. Further, the example shown in FIG. 2B shows that the portion of the upper layer 36 which is not shaded is 1.5 mm or less. In FIG. 2A, the white circle Q0 indicates the lower layer (first
The position of the support provided on the layer 35 is shown.

(C) Next, as shown in FIG. 2C, the support forming portion Q is formed on the outer peripheral portion of the support forming region P.
1, Q2 is set, and the support forming section Q3 is set at predetermined intervals where the interval is equal to or more than the predetermined interval inside the support forming area P (S4). The support forming section first sets the support forming section Q1 prior to the corner, and then sets the support forming section Q2 at a predetermined interval between the corners on the outer periphery. The outer peripheral portion and the lower layer 35
If the distance from the outer peripheral portion is longer than a predetermined interval, the support forming portion Q3 is set at a predetermined interval.

The predetermined interval is an interval that does not cause deflection while both ends are supported, and can be set wider than the above-mentioned fixed distance (corresponding to a cantilever). And, for example, about 3 to 20 mm, preferably 3 to 1 mm.
About 0 mm, more preferably about 4-6 mm spacing,
For example, it is set to be about 5 mm. When the interval between the support forming regions does not become an integral multiple of the predetermined interval set in advance, the predetermined interval is equally divided so that the interval is equal to or less than the predetermined interval, and the support forming unit is provided. That is, when the portion protruding from the lower layer 35 is 1.5 mm or more, a support forming portion is set at a corner on the outer periphery, and a predetermined interval (for example, 5 m) is set between the corners on the outer periphery.
m) The support forming section is set so as to be less than or equal to or less than a predetermined interval.

The corner portion may be one in which the outer peripheral portion changes discontinuously and forms an angle of about 120 ° or less, for example.
As shown in, even if the arc is formed in an arc and changes continuously, a portion C whose extension is a corner or a portion D formed in a projection shape is also treated as a kind of a corner. be able to.

(D) Thereafter, the layer 36 on which the support forming portion is set and the layer 35 below the layer 36 (only one lower layer is shown in FIG. 2 but all the layers below it are targeted). ) Of the support forming part Q (Q1 to Q
A support is formed at the position 3) (S5).

The support design apparatus in the stereolithography method of the present invention is formed so that this step can be executed by a computer. The support design apparatus slices three-dimensional data of a three-dimensional model in the horizontal direction and outputs two-dimensional data of the outer shape of each layer. Means for forming, and means for measuring the distance between the outer peripheral portions of the sliced adjacent two layers, and a region sandwiched between the outer peripheral portion of the upper layer and the outer peripheral portion of the lower layer when the distance is a certain value or more Means for specifying the support forming region, means for setting the support forming portion at a predetermined interval between the outer peripheral portion of the support forming region and the outer peripheral portion and the outer peripheral portion of the lower layer, and the support forming portion is set. Means for forming a support at a position of the support forming portion below the layer and the layer. The specific contents of each means are the same as those described with reference to the above-described flowchart.

According to the support forming method and the design apparatus of the present invention, the rate of shape change between adjacent layers is checked based on contour line data obtained by slicing a three-dimensional model in parallel to a horizontal plane. Even a part that cannot be seen as a shadow in the projection view can be grasped reliably. Therefore, the support can be reliably formed at the center or the end even in the hanging portion or the overhanging portion. Therefore, the support forming operation can be automatically performed without unnecessarily increasing the number of supports and without having to manually check and add a support forming place. As a result, even for a complicated three-dimensional model, the support can be easily formed, and the operation of removing the support after the resin is cured becomes easy, and the three-dimensional model can be manufactured at low cost by the optical molding method.

In the above-mentioned example, it is assumed that the upper layer is formed continuously, but in the case of the hanging portion 30a shown in FIG. 5B, it is shown in FIG. 3B. As described above, the hanging portion 36a appears in a portion away from the lower layer 35. In such a case, since the separation portion 36a can be recognized from the outer shape data of the upper layer 36, the lower layer 35
Regardless of the distance to the outer peripheral portion, the support forming portion is set at the central portion or the outer peripheral portion of the separation portion 36a, and if the region is large, the support forming portion is set at the above-described predetermined interval therebetween. By doing so, it will not be a floating island.

As shown in FIG. 3 (c), when the upper layer 36 is not separated but has a bent portion 36b, even if the distance E to the outer peripheral portion of the lower layer 35 is small,
The distance along the edge of the bent portion is E + F, and it is preferable that the sagging force be taken into account in E + F. Therefore, when there is such a bent portion, it is preferable to consider the above-mentioned fixed distance and predetermined interval in the distance along the bent portion. In this case, cut the bent part appropriately,
It can be easily obtained by adding the distance on the center line. It is to be noted that the same applies to the case where the bent portion is not angularly bent and is formed in an arc shape.

In each of the above-described examples, only the change between adjacent layers is considered. However, even if the change between the layers is small, the change may increase when accumulated. In such a case, it is preferable to add or delete the support forming portion set as described above based on the cumulative change of a plurality of continuous layers.

For example, in the case of a three-dimensional model 30 having an inverted pyramid shape as shown in FIG. 4A, the distance between the outer peripheral portions between adjacent layers is smaller than 1.5 mm, and the support forming portion for the protruding portion is set. Not done. But this is 10
When the number of layers is increased to 20 layers, the distance of the protruding portion from the lowermost layer becomes considerably large and becomes unstable. In such a case, the support forming portion is set at a position where the protruding portions are accumulated to have a predetermined size, or 10 layers or 2 layers are formed.
It is preferable to form the support 40a and 40b by setting the support forming portion for each of a fixed number of layers such as every zero layer. In this case, the surrounding locations and intervals are formed so as to be equal to or less than a predetermined interval with priority given to the corners as described above.

FIG. 4B shows an example in which, when there is a thin layer protruding portion between considerably thick layers, even if the protruding portion 36c from the outer peripheral portion of the lower layer 35 is larger than the predetermined distance A, The sagging problem is gone. That is, there is no problem up to about 3 mm if the thickness is about one layer even if it is larger than about 1.5 mm. Therefore, depending on the state of the layers to be laminated, the support forming portion formed in such a protruding portion can be eliminated. In particular, in the case of such a thin layer, if the support is formed, the thin layer of the main body is easily damaged when the support is removed, so it is preferable that the support is not provided as much as possible,
It is preferred that such a cumulative consideration be taken.

Note that these preferred methods can be added to the above-described design apparatus in the same manner, and a design apparatus that adds support with even higher precision can be obtained.

[0039]

According to the present invention, even when a three-dimensional model having a complicated shape different from a projected view is manufactured by stereolithography, the support is formed at a very accurate position and almost fully automatically. can do. As a result, a manual operation by human intuition is not required, and even for a three-dimensional model having a complicated shape, a support position is easily designed, and a three-dimensional model can be produced in a short time at low cost.

[Brief description of the drawings]

FIG. 1 is a flowchart of an embodiment of a support forming method according to the present invention.

FIG. 2 is an explanatory diagram of an example of setting a support forming unit according to the present invention.

FIG. 3 is an explanatory diagram in the case of a special shape between adjacent layers obtained by slicing a three-dimensional model.

FIG. 4 is an explanatory diagram of an example of adding or deleting a support forming unit by adding a judgment based on the accumulation of sliced layers.

FIG. 5 is a conceptual explanatory diagram in the case of producing a three-dimensional model by an optical shaping method.

FIG. 6 is an explanatory diagram of a specific process when a three-dimensional model is produced by a stereolithography method.

FIG. 7 shows a case where a three-dimensional model is produced by an optical molding method.
It is an explanatory view of an adhesion state between adjacent layers and an explanatory view of a problem that occurs when there is no support at an appropriate position.

[Explanation of symbols]

 30 solid model 35 lower layer 36 upper layer 40 support

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Michihiko Hasegawa 2-5-5 Keihanhondori, Moriguchi-shi, Osaka F-term in Sanyo Electric Co., Ltd. 4F213 AA44 WA25 WB01 WL03 WL12 WL62 WL93

Claims (7)

[Claims] 1. A data of a three-dimensional model is divided into layers at a constant thickness in parallel with a horizontal plane to create data of an outer shape of each layer. (B) An outer periphery of two adjacent layers of each of the divided layers By measuring the distance between, the outer peripheral portion of the upper layer of the two adjacent layers,
A portion that is at least a predetermined distance from the outer peripheral portion of the lower layer is defined as a support forming region, and (c) an outer peripheral portion of the support forming region and a support forming portion at a predetermined interval between the outer peripheral portion and the outer peripheral portion of the lower layer. (D) forming a support at a position of the layer on which the support forming portion is set and the position of the support forming portion below the layer. 2. When there is a corner at the outer peripheral portion of the support forming region, the support forming portion is set preferentially at the corner, and the support forming portion is provided at a predetermined interval on the outer peripheral portion sandwiched between the corners. The support forming method according to claim 1, further comprising setting a support forming unit. 3. The method according to claim 1, wherein the upper layer has a part separated in a plane, and the separated part is outside the outer peripheral part of the lower layer, the support forming part is further set in the separated part. 2. The support forming method according to 2. 4. Although it is continuous in a plane with the upper layer,
4. The support forming method according to claim 1, wherein when there is a bent portion, the support forming portion is set at the predetermined distance and the predetermined interval along the path of the bent portion. 5. The addition or deletion of the set support forming portion by a cumulative change of a plurality of continuous layers in addition to a shape change between adjacent layers.
The support formation method described. 6. When a distance of an outer peripheral portion between the upper layer and the lower layer is less than a predetermined distance, but the distance is accumulated toward the upper layer, a support is formed on the outer peripheral portion for each accumulated layer. The support forming method according to claim 5, wherein the support is set. 7. A means for slicing three-dimensional data of a three-dimensional model in a horizontal direction to form two-dimensional data of an outer shape of each layer, and a means for measuring a distance between outer peripheral portions of the two adjacent sliced layers. Means for specifying, as the support formation area, a region sandwiched between the outer periphery of the upper layer and the outer periphery of the lower layer when the distance is equal to or more than a predetermined value; and an outer periphery of the support formation region and an outer periphery of the lower periphery and the outer periphery of the lower layer. A stereolithography method comprising: means for setting a support forming portion at a predetermined interval between the support forming portion, and means for forming a support at a position where the support forming portion is set and at a position of the support forming portion below the layer. Support design equipment.