JPH0794149B2 - Laminated flat plate molding method in photo-curing molding method - Google Patents

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, and more particularly to a laminated flat-plate molding method in a photo-curing molding method capable of molding a laminated flat plate without causing warpage.

[0002]

2. Description of the Related Art A photo-curing molding method is used to form a three-dimensional model or a three-dimensional image. In this photo-curing molding method, the area corresponding to the bottom cross section of the three-dimensional image is normally irradiated with light on the liquid surface of the liquid resin that cures when irradiated with light, and the cross-section cured layer corresponding to the bottom cross section is first formed. Form. After that, an uncured liquid resin is introduced thereon, and this time, a region corresponding to the cross section immediately above is irradiated with light to laminate a cross-section cured layer. By repeating this, a stacked stereoscopic image is formed. When a flat plate such as a top plate of a desk is formed by such a technique, as shown in FIG. 10, first, light is irradiated to the entire area within a region corresponding to the flat plate, and the bottom layer 24 in the flat plate is formed. Modeling. Then, uncured liquid resin is introduced and the whole area 25 is irradiated again. By repeating this, the laminated flat plates are formed.

[0003]

When a laminated flat plate is formed by the photo-curing molding method, as shown in FIG. 11 (c), the end of the laminated flat plate is easily distorted into a shape curved upward.
The reason for this is presumed as follows. In this photo-curing modeling method, as shown in FIG. 11A, not only the upper cross-section hardened layer 25 is formed on the lower cross-section hardened layer 24, but the upper hardened layer 25 is integrated with the lower hardened layer 24. Need to be converted. Therefore, during the irradiation for forming the upper hardened layer 25, the lower cross-section hardened layer 24, particularly the upper surface side thereof, is overlapped and irradiated. For this reason, as shown in FIG. 11B, the upper side of one hardened layer is hardened more strongly, and accordingly, it is likely to shrink largely. Since such a tendency applies to all the layers, it is considered that the laminated flat plates are likely to have an unintended distorted shape in which both ends thereof are curved upward (see FIG. 11C). Therefore, the present invention proposes a laminated flat plate molding method in a photo-curing molding method capable of molding a laminated flat plate having a shape faithful to the design without causing warpage.

[0004]

In order to solve the above technical problems, in the present invention, when a laminated flat plate is formed by a photo-curing molding method, a layer in which an uncured portion is left is formed by irradiating with irradiation at a distance. And a step of curing the uncured portion at the time of curing the upper layer, in the photocuring modeling method characterized by forming a laminated flat plate while offsetting the strain associated with curing. Created a laminated flat plate manufacturing method.

[0005]

According to the above-mentioned method, the layer in which the uncured portion remains is interposed, and the uncured portion is cured during the formation of the upper layer, so that the shrinkage stress due to the curing is offset and a flat plate with less distortion is formed. To be done.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will now be described with reference to FIG.
The case where the laminated flat plate 12 shown in FIG.

First, the three-dimensional shape of the laminated flat plate 12 is designed using a three-dimensional CAD system. As a result,
Three-dimensional shape information of the laminated flat plate 12 is defined by the three-dimensional CAD system. Then, the shape of the cross section when the laminated flat plate 12 is horizontally sliced with a constant thickness is defined. By irradiating the surface of the liquid resin with laser light based on this cross-sectional shape, the laminated surface is formed. In the photo-curing modeling method, as shown in FIG. 2, the surface of the liquid photo-curable resin 8 is irradiated with a beam 9 of strong laser light to cure the resin 8 in the irradiated region, By stacking several layers, a three-dimensional cured resin image is created. The resulting shape is determined by the trajectory of the beam 9.

That is, as schematically shown in FIG. 2, a spot of the laser beam 9 is applied to the surface of the photo-curable resin 8 filled in the tank, and the laser beam 9 is two-dimensionally scanned by the scanner 10. By moving, a part of the surface is solidified. Then, the solidified one is made to sink from the liquid surface by the stage 11 by the thickness of one layer, and one layer of the liquid resin 8 is introduced onto the solidified portion. Next, this liquid portion is similarly solidified. This solidified image is layered and integrated on the lower solidified image. By repeating this, the layers are layered one by one. In this case, the laser light 9 is emitted by the scanner 10.
Can be freely scanned on the liquid surface.

In this embodiment, the laminated flat plate 12 is formed by irradiating the inside of the contour of the cross-sectional shape based on the data of the three-dimensional CAD system and laminating three layers. The shape of the spot of the laser beam 9 used is circular and its diameter is 0.5 mm. As shown in FIG. 1A, the laser beam 9 can reach the liquid resin 8 in a parabolic shape to a depth of about 1.7 times the thickness of one layer. Further, the laminated flat plate 12 shown in FIG.
It is a laminated flat plate having a thickness of 6 mm and is formed in a three-layer structure including layers each having a thickness of 0.2 mm. First, as shown in FIG. 3B, the beam 9 is scanned by the scanner 10 on the surface of the liquid resin 8 corresponding to the inside of the contour based on the sectional shape information of the first layer 1 of the laminated plate 12. . That is,
The inside of the contour is scanned in a folded shape in parallel with the X direction of FIG. At this time, the distance between the centers of the beams 9 is 0.8 times the diameter, and is actually 0.4 mm. Therefore, the beams 8 are emitted while overlapping each other by 0.1 mm. Therefore, the entire surface of the first layer 1 is irradiated without any gap.

The irradiation state of the cross section of the first layer 1 of the laminated flat plate 12 in the Y direction is shown in FIG. The beam 9 reaches the liquid resin 8 in a parabolic shape and forms an irradiation region 4 in the resin 8. This beam 9 irradiates the entire area of the first layer having a thickness of 0.2 mm, and this region 4 immediately starts to be polymerized by laser light stimulation and is cured. Usually, when a certain amount of liquid resin 8 cures, the volume of cured resin 8 decreases,
Contract. However, since the periphery of the first layer is filled with the liquid resin 8, distortion is unlikely to occur.

Next, when the stage 11 is lowered to lower the first layer 1 by a thickness of one layer (0.2 mm), new resin 8 is introduced onto the first layer 1. Figure 3 (b)
As shown in, the beam 9 is formed on the surface of the resin 8 in parallel with the X direction based on the sectional shape information of the second layer 2.
Are scanned. At this time, the center of the beam 9 has a diameter of 1.
The inside of the contour is scanned in a folded shape at intervals of 5 times.
That is, the distance between the centers of adjacent beams 9 is 0.75.
mm, and the beams 9 are radiated separately from each other without causing the beams 9 to overlap each other. As a result, as shown in the Y direction sectional view of FIG. 1, the irradiation region 5 by the beam 9 is formed in a band shape. The resin 8 in the beam irradiation region 5 in this second layer immediately polymerizes and hardens.

As shown in FIG. 1, the depth of the laser beam of this beam 9 reaches about 1.7 times the layer thickness. For this reason, the laser light of the beam 9 of the second layer 2 partially irradiates 4 to a depth of about 70% above the already cured first layer.
will be a. In such a double irradiation region 4a, the resin once cured is polymerized by receiving a light stimulus again. Therefore, the degree of polymerization of the resin is increased in this portion 4a. However, unlike the first curing, the resin is not newly replenished from the surroundings, so that the surroundings are pulled to cure and shrink. That is, as shown in FIG. 1B, as a whole of the first layer 1, the stress of contracting the upper surface side acts to cause the both ends to warp upward. Although the arrow indicates the Y direction, the contraction stress actually acts in all the surrounding directions.

On the other hand, at the same time, a band-shaped uncured portion 6 having a width (0.25 mm) which is half the diameter of the beam 9 is formed between the irradiation regions 5.

Next, the second layer 2 is further lowered by the stage 11, and new liquid resin 8 is introduced. The surface of the liquid resin 8 is scanned with the beam 9 in parallel with the X direction by the scanner 10 based on the sectional shape information of the third layer 3. The scanning method for the third layer 3 is similar to that for the first layer 1. That is, the beams 9 irradiate the entire surface without gaps while overlapping each other by 0.1 mm. By this irradiation, the irradiation region 7 as shown in FIG. 1 is formed. Since the beam 9 reaches this layer thickness,
The entire third layer 3 is cured by this irradiation.

Further, this beam 9 is located at about 7 above the second layer 2.
Since it reaches 0%, the double irradiation region 5a is partially formed above the irradiation region 5 of the second layer 2. In the double irradiation area 5a, as in the case of the first layer 1,
Since the polymerization further proceeds, a contraction stress acts on this region 5a.

Further, by the irradiation this time, the uncured portion 6 of the second layer 2 is newly irradiated, and the irradiation region 6a is formed in the second layer. In the irradiation area 6a, the liquid resin 8 is immediately hardened. In this region 6a, the uncured portion 6
Of these, since there is the liquid resin 8 in the region 6b that has not been irradiated this time, strain stress at the time of curing is not generated.
However, the portion 6b where the beam 9 is still unirradiated
In the above, due to the surrounding polymerization stimulus, the polymerization proceeds slowly but is cured. This portion 6b does not already have sufficient resin 8 and is not newly replenished. Therefore, at the time of curing, the surrounding cured portion is strongly pulled to try to polymerize. That is, a strong contraction stress acts on this uncured portion 6b.

As a result, a contraction stress acts on the upper double irradiation region 5a of the second layer 2 and a stronger contraction stress acts on the uncured portion 6b formed centering on the lower side. Therefore, the second layer 2 as a whole is shown in FIG.
The contraction occurs as shown by the arrow, and as a result, a downward warp is attempted. Although the arrow in FIG. 1B exemplifies the Y direction, it actually contracts in all surrounding directions. Therefore, the stress of the second layer 2 and the stress of the first layer 1 act to cancel each other. As a result, as a whole, the laminated flat plate 12 in which the warps are canceled as shown in FIG. 1C is formed.

In the conventional irradiation method in which the entire surface of each layer 1, 2 and 3 is scanned at equal intervals without any gaps, the upper part of each layer becomes a double irradiation area, and each layer 1, 2 and 3.
The contraction stress was acting on the upper surface side of No. 3. However, in this embodiment, as is clear from the cross-sectional view in the Y direction of the laminated flat plate 12 shown in FIG.
By interposing the layer 2 having the uncured portion 6b on which a contracting stress stronger than that on the second layer 4a having the double irradiation region 4a is interposed, Offset by layer 2 warpage.

By thus forming the separated irradiation layer 2, the uncured portion 6b having a strong shrinking action is formed on the lower side of the layers, and the shrinkage stress of the laminated layers 1 is reduced. Can be corrected and offset. Moreover, this canceling effect acts in all directions, and the entire laminated flat plate 12 is not warped.

Next, as a second embodiment of the present invention, FIG.
Laminated flat plate 13 modeled by the irradiation method shown in (b)
(See FIG. 4A) will be described as an example. In this embodiment, similarly to the first embodiment, a laminated flat plate 13 formed by laminating three layers having a layer thickness of 0.2 mm is formed. The apparatus and the basic operation in the photo-curing modeling method are the same as those in the first embodiment, but the scanning method of the beam 9 is different. First, FIG. 4 (b)
As shown in FIG. 6, as in the first embodiment, the inside of the contour of the cross section of the first layer 14 based on the three-dimensional shape information is parallel to the X direction in the drawing, and the irradiation interval is folded back at 0.8 times the diameter of the beam 9. Are scanned in a circular pattern. For this reason, the first layer 14 is irradiated with the beam 9 so that the entire surface thereof has no gap and the trajectories scanned are partially overlapped (by 0.1 mm).

The irradiation state of the cross section of the first layer 14 of the laminated flat plate 13 in the Y direction is shown in FIGS. 5 (a) and 6 (a). The beam 9 reaches the liquid resin 8 in a parabolic shape,
The irradiation area 17 is formed in the resin 8. This beam 9 irradiates the entire area of the first layer with a thickness of 0.2 mm, and this region 17 immediately starts to be polymerized by photostimulation and hardens.
Normally, when a certain amount of the liquid resin 8 is cured, the volume of the cured resin 8 decreases and shrinks. However, since the periphery of the first layer 14 is filled with the liquid resin 8, no distortion occurs. Therefore, no stress acts on this layer 14.

Next, when the stage 11 is lowered to lower the first layer 14 by the thickness of one layer (0.2 mm),
New resin 8 is introduced on the first layer 14. Figure 4
As shown in (b), the surface of the resin 8 is further scanned with the beam 9 parallel to the Y direction based on the sectional shape information of the second layer 15. At this time, the inside of the contour is scanned in a folded shape so that the centers of the beams 9 are spaced by 1.5 times the diameter. That is, the distance between the centers of the adjacent beams 9 is 0.75 mm, and the beams 9 are radiated separately from each other without causing the beams 9 to overlap each other. As a result, FIG.
As shown in the second layer 15 in the Y direction sectional view of FIGS. 6A and 6A, the irradiation region 18 by the beam 9 is formed in a band shape. Beam irradiation region 18 in the second layer 15
Immediately polymerizes and hardens.

Further, as shown in FIG. 5A, the second
Partially illuminated by the light of beam 9 illuminating layer 15 to a depth of about 70% above the already cured first layer 14.
7a will be performed. Such double irradiation area 17a
In (1), the resin 8 that has once been cured is polymerized by being again stimulated by light. Therefore, the degree of polymerization of the resin 8 is increased in this portion 17a. Therefore, as in the first embodiment, as shown in FIG.
As shown in (b), the contraction stress acts in all directions on the double irradiation region 17a, that is, on the upper surface side of the first layer 14.

On the other hand, at the same time, as shown in FIG. 6A, between the irradiation regions 18 of the second layer 15, a belt-shaped uncured portion 19 having a width (0.25 mm) which is half the diameter of the beam 9 is formed. Is formed.

Next, as the third layer 16, this second layer 15 is used.
New liquid resin 8 is introduced on top. The entire surface of the cross section of the third layer 16 is again scanned in parallel with the X direction at the same irradiation interval as that of the first layer 14. As shown in FIG. 5A, the third layer 16 is rapidly cured by this irradiation. Further, in the second layer 15, the double irradiation region 18
a is formed, and in the same manner as in the first embodiment, the contraction stress in all directions shown in FIG. 5B acts on the upper side of the second layer 15.
As a result, an upward warp occurs in the b section of the second layer 15, and the b section of the first layer 14 and the second layer 15 combined as shown in FIG. Try to cause a warp.

Further, as shown in FIG. 6 (a), the beam 9 reaches the uncured portion 19 and the resin 8 is cured in the irradiation region 19a. The portion of the second layer centered on the lower portion of the uncured portion 19 is the third layer 16
There is a portion 19b that the beam 9 does not reach even during the irradiation of. In this uncured portion 19b, shortage of the resin 8 occurs as in the first embodiment. That is, curing gradually progresses in a state where there is no sufficient resin 8 that can fill the uncured portion 19b. Therefore, as it cures, it tries to cure while pulling on the surrounding cure zone. That is, as shown in FIG. 6B, a strong contraction stress acts on this portion 19b. As a result, as shown in FIG. 6C, the first layer 14 and the second layer 15 have a combined section c, which tends to cause a downward warp.

As described above, in the first layer 14, the second layer 15, and the third layer 16, even if the scanning directions of the beams 9 in the respective layers are orthogonal to each other, the uncured portion 19b is interposed by the spaced irradiation. For what you can do,
Exactly the same. Therefore, the effect of canceling or correcting the shrinkage stress due to the uncured portion 19b can be similarly obtained. As a result, in this embodiment, the laminated flat plate 1
The upward warping stress generated in the b section of 3 and the downward warping stress generated in the c section cancel each other, so that the laminated flat plate 13 having no warpage is formed as a whole.

Next, as a third embodiment, a case of manufacturing the laminated flat plate 20 shown in FIG. 9B will be described as an example. In this embodiment, as in the first and second embodiments, the layer thickness is 0.
A laminated flat plate 20 formed by laminating three 2 mm layers is manufactured. The apparatus and the basic operation in the photo-curing molding method are the same as those in the above-described embodiments, but the scanning method of the beam 9 is different. First, as shown in FIG. 7A, the inside of the contour of the cross section of the first layer 21 based on the three-dimensional shape information is folded back in parallel with the X direction in the drawing with an irradiation interval of 2.0 times the diameter. To be scanned. That is, the distance between the centers of adjacent beams 9 becomes 1.0 mm, and as shown in FIG. 7B, the irradiation regions 21a of the beams 9 are irradiated separately without overlapping each other. . Further, thereafter, the scanning is performed in a folded shape in parallel with the Y direction in the drawing at the same irradiation interval. As a result, the beam 9 is irradiated in a band shape with a gap having the same interval (0.5 mm) as the diameter left, and a grid-shaped irradiation region 21a is formed. This irradiation area 21a
In, the resin 8 is quickly cured. Then, uncured portions 21b are formed at intervals of the diameter of the beam 9 between the grid-shaped irradiation regions 21a.

Next, the stage 11 is lowered and the first layer 2
1 is lowered by the thickness of one layer, and new resin 8 is introduced on the first layer 21. The inside of the contour is illuminated based on the sectional shape information of the second layer 22. In this irradiation, first, as shown in FIG. 8A, the irradiation interval is set to 1.3 times the diameter of the beam 9 in parallel with the X direction, and scanning is performed in a folded shape. That is, scanning is performed so that the distance between the centers of the beams 9 is 0.65 mm. Further, the scanning is performed in a folded shape in parallel with the Y direction at the same irradiation interval.
That is, on the second layer 22, as shown in FIG. 8B, the beam 9 is irradiated in a strip shape in both the X direction and the Y direction, leaving a gap (0.15 mm) of 0.3 times the diameter. It As a result, the irradiation region 2 is left, leaving a slight uncured portion 22b.
2a is formed. Although most of the area 22a is a double irradiation area, since the irradiation is performed in a state where the resin 8 can be replenished, the area 22a is cured without any contracting stress.

By irradiating the second layer 22, the first layer 22
Also in the layer 21, a double or triple irradiation region is formed above it. In this double or triple irradiation region, although not shown, a contraction stress acts on the periphery like the first and second embodiments. Further, in the uncured portion 21b of the first layer 21, the upper side of the uncured portion 21b is partially cured by the irradiation of the second layer 22, but the unirradiated portion centered on the lower side of the second layer 22 is As in the first and second embodiments, a shortage of the resin 8 occurs. That is,
Curing proceeds gradually without sufficient resin that can fill the uncured portion. Therefore, as it cures, it tries to cure while pulling on the surrounding cure zone. That is, a strong contraction stress partially acts on the lower side of the first layer 21. Since the action of the contracting stress on the lower side is larger than the contracting stress on the upper side of the first layer 21, the stress that tends to warp downward is generated in the first layer 21.

Next, when the stage 11 is lowered and the second layer 22 is lowered by the thickness of one layer (0.2 mm),
New resin 8 is introduced onto this second layer 22. Figure 9
As shown in (a), the surface of the resin 8 is further irradiated with the inside of the contour thereof based on the sectional shape information of the second layer 22. In the irradiation of the third layer 23, first, the irradiation interval is set to 1.1 times the diameter of the beam 9 in parallel with the X direction, and scanning is performed in a folded shape. That is, scanning is performed so that the distance between the centers of the beams 9 is 0.55 mm. Furthermore, Y
The scanning is performed in a folded shape at the same irradiation interval in parallel with the direction. That is, in the third layer 23, as shown in FIG. 9B, the beam 9 has a diameter of 0.1 mm in both the X direction and the Y direction.
Irradiation is performed in a strip shape leaving a double gap (0.05 mm).
As a result, the irradiation region 23a is formed, leaving a very small uncured portion 23b. Although most of the area 23a is a double irradiation area, since the irradiation is performed in a state where the resin 8 can be replenished, the area 23a is cured without any shrinkage stress.

By irradiating the third layer 23, the second layer 23
Also in layer 22, double or triple irradiation areas are formed above it. In this double or triple irradiation region, although not shown, a contraction stress acts on the periphery like the first and second embodiments. Furthermore, in the uncured portion 22b of the second layer 22, the upper side of the uncured portion 22b is partially cured by the irradiation of the third layer 23, but the unirradiated portion centered on the lower side of the second layer 22 is As in the first and second embodiments, a shortage of the resin 8 occurs. That is,
A strong contraction stress partially acts on the lower side of the second layer 22. However, the contraction stress in this layer 22 is
Compared with the layer 21, the laminated flat plate as a whole has a small action. This is because the uncured portion 22b itself is small in the second layer 22, and the portion to which light does not reach even when the third layer 23 is irradiated is small. Therefore, unlike the first layer 21, the second layer 22 is warped upward. As a result, it acts so as to cancel or correct the warp of the first layer 21,
A laminated flat plate 20 having no warpage as a whole is formed.

As described above, in the first layer 21, the second layer 22, and the third layer 23, even when the scanning directions of the beam 9 are made to be orthogonal to each other, the uncured portions 21b and 22b are interposed by the spaced irradiation. Can be made. Further, by changing the irradiation interval in each layer, the ratio of the uncured portion can be adjusted and the degree of the action of the contraction stress can be adjusted.

It is to be noted that how many layers having an uncured portion and how the layers having an uncured portion after being irradiated on the entire surface are intervened to obtain a laminated flat plate having no warp. , Irradiation scanning interval, direction setting, beam intensity, scanning speed, etc. Therefore, in order to obtain a warped laminated flat plate, one layer having an uncured portion may be required for a plurality of irradiation layers, and vice versa. Further, the layer having an uncured portion may be interposed alone or may be laminated and interposed.

[0035]

As described above, according to the present invention, when a laminated flat plate is formed by the photo-curing molding method, a new shrinkage is caused by interposing a layer having an uncured portion which is not irradiated with a beam. It is possible to generate a stress, and the contracting stress can correct and cancel the warping action due to the conventional contracting stress. Therefore, an accurate shape with less distortion can be formed.

[Brief description of drawings]

FIG. 1 is a-a of a laminated board in the first embodiment shown in FIG.
It is the figure which matched the line expanded sectional view, the action figure of contraction stress, and the figure which shows the cancellation state of contraction stress.

FIG. 2 is a schematic diagram of a method for manufacturing a laminated plate by a photo-curing molding method.

FIG. 3 is a diagram showing a beam scanning method for a laminated plate and each layer of the laminated plate.

FIG. 4 is a diagram showing a beam scanning method for a laminated plate and each layer of the laminated plate of the second embodiment.

5 is a diagram in which the bb line enlarged cross-sectional view, the contraction stress action diagram, and the contraction stress cancellation state of the laminated plate of FIG. 4 are associated with each other.

FIG. 6 is a diagram in which the c-c line enlarged cross-sectional view of the laminated plate of FIG. 4, the action diagram of the contraction stress, and the diagram showing the state of cancellation of the contraction stress are associated with each other.

FIG. 7 is a perspective view showing a beam scanning method and an irradiation area of a first layer of a laminated board of a third embodiment.

FIG. 8 is a perspective view showing a beam scanning method and an irradiation area of a second layer of the laminated board of the third embodiment.

FIG. 9 is a perspective view showing a beam scanning method and irradiation area of a third layer of the laminated board of the third embodiment.

FIG. 10 is a perspective view showing a beam scanning method in a conventional modeling method.

FIG. 11 is a diagram in which an enlarged cross-sectional view of a laminated plate by a conventional molding method, an action diagram of shrinkage stress, and a diagram showing a state of offsetting shrinkage stress are associated with each other.

[Explanation of symbols]

 2, 15, 21, 22 ... Layers in which uncured portions remain 3, 16, 22, 23 ... Upper layers 6, 19, 21b, 22b ... Uncured portions 12, 13, 20 ... Laminated flat plate

Claims (1)

[Claims] 1. A step of forming a layer in which an uncured portion is left by irradiating the layered plate in a spaced manner when a laminated flat plate is formed by a photo-curing molding method, and the step of curing the upper layer when the layer is not cured. And a step of curing the cured portion, and forming a laminated flat plate while offsetting the strain due to curing, thereby forming a laminated flat plate modeling method in a photo-curing modeling method.