JPH07100936A - Photosetting shaping method for obtaining closed skin - Google Patents

Abstract

PURPOSE:To extend an application range of a photosetting shaping method to give the convenience of the photosetting shrping method in various fields by a method wherein an area is calculated based on a boolean operating formula, and in a light emitting process a sight is emitted also to the area calculated in the aforesaid process. CONSTITUTION:In a photosetting shaping method for shaping a three-dimensiolal object provided with a skin of a desired shape by integrally laminating section profile set layers, where the section area of the N-th layer is [N], areas are calculated by a boolean operating formulr [[N-9147-28}-[N-1]] OR [[N]-[N+1]]. To a light emitting process for the N-th layer, a process for emitting a light to the areas calculated in the aforasaid calculating process is added. As a result, areas 40-42 are given for a downward surface by [N]-[N-1]. Areas 43-46 are given for an upward surface by [N]-[N+1]. The area 43 is given for a maximum prokected part by [N]-[N+1]. An area 48 is given for a lowermost section. An area 47 is given for an uppermost section.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photo-curing molding method.

[0002]

2. Description of the Related Art For example, when data showing a three-dimensional shape as illustrated in FIG. 1 is given, a photo-curing molding method for molding a three-dimensional object having a three-dimensional shape determined by the data has been put into practical use. JP-A-56-144478 discloses the basic structure thereof. The photo-curing modeling method uses a photo-curable liquid that has a property of being cured when exposed to light. Of the liquid surface of this photocurable liquid, a region corresponding to the lowermost cross section of the cross section obtained by slicing the desired shaping shape into a number of layers is irradiated with light. Then, a cross-section hardened layer having a planar shape corresponding to the bottom cross-section is formed. After coating the surface of the cross-section cured layer with an uncured photocurable liquid,
The area corresponding to the th section is irradiated with light. Then, a cross-section hardening layer having a plane shape corresponding to the second cross-section from the bottom is newly formed, and at the same time, the cross-section hardening layer is laminated and integrated with the cross-section hardening layer previously formed. By repeating this, a three-dimensional object having a desired shape is formed.

For the purpose of shortening the molding time, a photo-curing molding method for molding a hollow or honeycomb-shaped three-dimensional object whose outer skin has a desired molding shape has been put into practical use.
This will be described with reference to FIGS. 1 and 10. Figure 10
2 shows a molding process by a photo-curing molding method for molding a three-dimensional object having an outer cover having a desired molding shape of FIG. 1. In this case, first, data indicating a cross-section group for slicing a desired shaping shape into a plurality of layers is obtained, and photo-curing shaping is performed based on the cross-section data. FIG. 10 exemplifies a case where the desired shape of FIG. 1 is sliced into 9 layers and then molded. Although the number of slice layers is remarkably reduced in FIG. 10 for simplification of the drawing, it is actually formed by slicing into an extremely large number of layers.

Now, taking the third layer from the bottom as an example, the liquid surface of the photocurable liquid is irradiated with light based on the data showing the cross section 103a of the third layer. At this time, light irradiation is performed along the contour 103b of the cross section 103a. As a result, a layer in which the contour of the third section is hardened (this is referred to as a cross-section hardening layer) 103c is formed. After the cross-section contour hardening layer 103c is formed, the surface thereof is coated again with the uncured photocurable liquid. Then, after coating, light irradiation is performed along the contour of the adjacent cross section, in this case, the cross section of the fourth layer. As a result, the fourth layer cross-section contour hardening layer 104c is formed and laminated and integrated with the cross-section contour hardening layer 103c. In this way, when the light irradiation step and the coating step are set as one cycle and this cycle is repeated, a three-dimensional object having a skin in which cross-sectional contour hardening layers are laminated and integrated is formed. When the cross section handled in the light irradiation step repeatedly executed here is switched to an adjacent cross section each time the cross section is cured, the outer skin formed by laminating and integrating the cross-section contour hardening layers has a desired molding shape. The bottom section 101 and the top section 1
As for 09, not only the contour but also the inner region is irradiated with light to normally close the outer skin. The present invention is an improvement over the conventional photo-curing molding method described above.

[0005]

FIG. 11 shows an outer skin 11 formed by laminating and integrating the cross-sectional contour hardening layers of FIG.
0 shows the appearance. In the figure, the outer layer 110 is not so close to the desired shape to be formed in FIG. 1 because of the thicker layer, but in reality, since the layer thickness is as thin as about 0.1 mm, it is actually formed. The outer appearance of the outer cover 110 closely resembles the desired shape of FIG.

As well shown in FIG. 11, one of the problems of the conventional method is that the outer skin has holes 111 and 112 and the inner and outer skins communicate with each other.
When the thickness of one layer is reduced as described above, the adjacent cross-sectional shapes become similar and the holes 111 and 112 become smaller. And if made very thin, the holes 111 and 112 should theoretically not be formed. However, in reality, the thickness of one layer is about 0.1 mm, and it cannot be thinned unnecessarily. Even if the thickness is reduced to about 0.1 mm, if the gradient of the desired shape is gentle, the contours of the respective cross sections may not be connected and the holes 111 and 112 may be formed.

Attempts to address this problem have been attempted by the inventors. The first attempt is to perform a Boolean operation formula [N]-when forming the cross-sectional contour hardening layer of the Nth layer.
The area is obtained by [N-1] and the area is also irradiated with light. Here, [N] is the cross-sectional area of the Nth layer, and [N-1] is the cross-sectional area of the N-1th layer. FIG. 2 shows an area calculated by the Boolean arithmetic expression of [N]-[N-1]. Although the display on the depth side of the drawing is omitted in FIG. 2, it is extended to the back side as in FIG. In FIG. 2, reference numeral 20 is [2]-[1], number 2
1 indicates [3]-[2] ..., and number 23 indicates [5]-[4]. On the upward plane, [N]-[N-1] becomes "empty". For example, looking at the 7th layer [7]-
[6] = zero (because [6] is larger than [7], it becomes empty).

Now, FIG. 5 shows a cross-sectional view of the laminated body of the cross-sectional contour hardening layer shown in FIGS. 10 and 11. Note that FIG. 5 exemplifies a case where the thickness of one layer is reduced to half as compared with the cases of FIGS. 10 and 11. Even if the thickness of one layer is reduced,
Because the slope is gentle, the contours are not connected and the hole 5
It is understood that there are 1 to 58. On the other hand, FIG. 6 shows a cross section of the cured layer when light irradiation is also applied to the [N]-[N-1] region described in FIG. As a result of the addition of light irradiation in regions 20-23, holes 55-
It is understood that although 58 is closed, holes 51-54 are still formed.

Therefore, the applicant has made a second attempt as follows.
[[N]-[N-1]] OR [[N-1]-[N]] is determined to be a region based on the Boolean arithmetic expression, and this region is also irradiated with light. FIG. 3 shows [[N]-[N-1]].
The area | region calculated | required by the formula of OR [[N-1]-[N]] is shown. In the case of FIG. 2, since [N-1] is larger than [N] on the upward surface, the [N]-[N-1] area is empty, but in this case, [N-1]- Since the formula [N] is valid, the regions 34 to 37 are calculated even on the upward surface.

FIG. 7 shows that [[N]-
The cross section of the hardened layer when light is also applied to the regions 30 to 37 obtained by the Boolean arithmetic expression of [N-1]] OR [[N-1]-[N]] is shown. Obviously, in FIGS. 5 and 6, the remaining holes are closed. However, this technique still has two problems. The first problem is that, as a result of excessive irradiation to close the holes, the upper surface is excessively hardened upward, and the downward surface is excessively hardened downward, and as a result, the thickness becomes thicker than the desired shape. That is. The second problem is that the bottom section and the top section are not closed, and the bottom section and the top section must be closed by different processing.

The present invention is concerned with the above-mentioned two problems, that is, the treatment for preventing the formation of the holes 51 to 58 and the like in order to close the lowermost section and the maximum section without the thickness of the shaped article becoming excessively thick. By a method that does not require another treatment, in other words, a treatment for preventing the generation of the holes 51 to 58, the holes in the lowermost cross section and the uppermost cross section are closed at the same time.

[0012]

According to the present invention, a liquid surface of a photocurable liquid is irradiated with light along a contour of one cross section based on data indicating a cross section group for slicing a desired shaping shape into a plurality of layers. By repeating the step and the step of coating the surface of the cross-sectional contour hardening layer formed in the light irradiation step with an uncured photocurable liquid while switching the cross section handled in the light irradiation step to an adjacent cross section. , A modification of the conventional photo-curing molding method for molding a three-dimensional object having an outer skin exhibiting a desired molding shape in which cross-sectional contour hardening layers are laminated and integrated,
When the cross-sectional area of the Nth layer is [N], [[N] −
[N-1]] OR [[N]-[N + 1]] calculating a region based on a Boolean arithmetic expression, and a light irradiation process for the Nth layer, in the region calculated in the calculating process. Is also characterized by adding a step of light irradiation. Here, [N-1] is the cross-sectional area of the (N-1) th layer, and [N + 1] is the cross-sectional area of the (N + 1) th layer.

[0013]

Now, FIG. 4 shows [[N]-[N-1]] OR.
The area | region calculated | required by the Boolean arithmetic expression of [[N]-[N + 1]] is shown. [N] is [N-1] on the downward surface
[N] because it is larger and [N] is smaller than [N + 1]
-[N + 1] becomes "empty". As a result, [N]-[N-
1] areas 40 to 42 are provided. On the upside, conversely, [N]-[N-1] becomes "empty" and [N]-[N +
1] provides areas 43-46. [N] at maximum overhang
The larger one of-[N-1] and [N]-[N + 1],
In this case, [N]-[N + 1] gives the area 43. Of particular note is that the bottom section is also provided with a region 48 and the top section is also provided with a region 47. In the calculation of [N]-[N-1] in the bottom cross section, [N-1] is "empty", so it becomes [N], and in the top cross section, [N]
This is because in the calculation of − [N + 1], [N + 1] is “empty” and thus becomes [N].

Now, in FIG. 8, in addition to the cross-sectional contour hardening layer, light is also irradiated to the area obtained by the Boolean arithmetic expression of [[N]-[N-1]] OR [[N]-[N + 1]]. The cross section of the laminated hardened layer formed at this time is shown. As a result, the following can be seen. (1) All the holes 51 to 58 formed in FIG. 5 are closed. Although it is shown in the drawing that a minute gap is left, the hardened portions are actually connected to each other, and no hole is formed. (2) The thickness of the overhang does not become too thicker than the desired shaping shape. (3) The bottom section and the top section are naturally closed. It should be noted that the above phenomenon is not sometimes observed for the example of FIG. 1, but applies to all cases. The figure is merely an example.

[0015]

FIG. 12 shows an example of a procedure for carrying out the method of the present invention. First, in step S2, three-dimensional shape data designed by the three-dimensional CAD system is input to the photo-curing modeling apparatus. And after step S4, it is performed by a computer or an actuator in the photo-curing modeling apparatus. 12
The procedure (1) shows a procedure for forming a three-dimensional object by stacking M layers in total. In step S4, 1 is designated as N. Here, N represents the layer number, 1 corresponds to the bottom cross section, and M corresponds to the top cross section. In step S4, the bottom cross section is designated. Note that steps S6 to S12 are repeatedly executed for N = 1 to M by the process of returning from step S14 and step S16 to step S6.

In step S6, the cross-sectional area [N] of the Nth layer is calculated. A step S8 calculates the contour based on [N]. The calculated data is stored as L (N). Step S10 is [[N]-[N-1]] OR
The operation is performed based on the Boolean operation expression of [[N]-[N + 1]], and the solution is stored as P (N). Step S12
Designates a grid-like region Q (N) inside [N]. This is a process for reinforcing the interior of the three-dimensional object in a lattice shape, and when forming a hollow object, this step S12 is omitted. The above processing is executed for N = 1 to M, and then waits for a command to start modeling in step S18.

When modeling is started, first, step S20.
Specifies the bottom section. As a result, step S2
At 2, the area of Q (1) OR P (1) OR L (1) is irradiated with light. As described in FIG. 8, in this case P (1)
Since Q (1) and L (1) are included in the area, the area 48 is eventually entirely irradiated with light. After irradiation, step S24 in FIG.
The uncured photocurable liquid is coated on the cured surface 48. Then step S22 is executed again, this time Q
(2) OR P (2) OR L (2) is irradiated. In this case, P (2) is "empty", the contour is illuminated by L (2) and the interior of the contour is illuminated by Q (2) in a grid pattern.

The above processing is executed for all layers, and
The outer skin with the hole shown in FIG. Further, in this case, since step S12 is added, a lattice is formed inside the outer skin, and a three-dimensional object in which the outer skin is reinforced by the lattice from inside is formed. If the internal grid is unnecessary, step S12 need not be executed.

The present invention is also useful for modeling a solid three-dimensional object. FIG. 9 shows contours and [[N]-[N-1]] OR.
All the layers are illuminated with light in the area calculated by the Boolean arithmetic expression of [[N]-[N + 1]] (hatched portion in the figure), and the interior of the cross section (portion surrounded by the hatch) is alternated. Illuminated (see arrow 90)
The case is shown. Since the outer layer is irradiated with light for each layer, the outer shape is shaped accurately and firmly. On the other hand, the inner region is roughly illuminated and does not harden strongly. By doing so, the modeling time of the solid model can be shortened, and if the interior is hardened strongly, the internal stress becomes strong and the tendency of distortion can be suppressed.

[0020]

EFFECTS OF THE INVENTION According to the present invention, since the outer skin is securely closed, for example, when a three-dimensional object formed by this method is used as a casting model, casting sand etc. does not leak and casting It is possible to reliably model the model. In this way, the application range of the photo-curing modeling method is expanded, and the convenience of the photo-curing modeling method can be enjoyed in various fields.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a desired shaping shape.

FIG. 2 is a diagram showing a region obtained by [N]-[N-1].

FIG. 3 [[N]-[N-1]] OR [[N-1]-
The figure which shows the area calculated by [N]

FIG. 4 [[N]-[N-1]] OR [[N]-[N +]
1]] showing the area determined by

FIG. 5 is a view showing a cross section of a cross-section contour hardening layer.

FIG. 6 is a diagram showing a cross section when light is irradiated to a region [N]-[N-1] in addition to the cross-section contour hardening layer.

FIG. 7: [[N]-[N-1]] in addition to the cross-sectional contour hardening layer
The figure which shows the cross section when light is irradiated to the area | region of OR [[N-1]-[N]].

FIG. 8: [[N]-[N-1]] in addition to the cross-sectional contour hardening layer
The figure which shows the cross section when light is irradiated to the area | region of OR [[N]-[N + 1]].

FIG. 9 is a diagram showing a cross section when the outer skin is irradiated with respect to all layers and the inside is irradiated with respect to the septum.

FIG. 10 is a view showing a cross-sectional contour hardening layer.

FIG. 11 is a view showing a state in which cross-sectional contour hardening layers are laminated.

FIG. 12 is a processing procedure diagram of one embodiment.

[Explanation of symbols]

 S22 light irradiation step S24 coating step S25, S26 processing for switching cross sections 101C to 109C cross section contour hardening layer 40 to 42, 48 [N]-[N-1] 43 to 47 [N]-[N + 1]

Claims (1)

[Claims] 1. A step of irradiating a liquid surface of a photocurable liquid with light along a contour of one section based on data showing a group of sections for slicing a desired shaping shape into a plurality of layers, and the light irradiation step. By repeating the step of coating the surface of the cross-sectional contour-cured layer to be formed with a photocurable liquid in an uncured state, by repeating the section of the light irradiation step while switching the section to an adjacent section,
In the photo-curing molding method for molding a three-dimensional object having a skin having a desired shape, the cross-sectional contour hardening layers are laminated and integrated, and when the cross-sectional area of the Nth layer is [N], a Boolean arithmetic expression [[ N]-[N-1]] OR [[N]-[N +
1]] is added to the step of calculating the region based on the formula and the step of irradiating the light for the Nth layer, and the step of irradiating the region calculated in the calculating step is also added. A photo-curing molding method that provides the outer skin.