JP2671534B2 - 3D shape forming method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for molding and producing an article having a three-dimensional three-dimensional shape by using a photocurable resin that is cured by irradiation with light.

[Conventional technology]

The method of forming a three-dimensional shape using a photo-curable resin,
As a method that can easily and accurately form a complicated three-dimensional shape without using a molding die or special processing tools, it is considered to be used for manufacturing various product models and three-dimensional models. And is disclosed, for example, in JP-A-62-35966.

FIG. 14 shows an example of a conventional general method for forming a three-dimensional shape using a photocurable resin.
A resin table 81 accommodating 82 is provided with a vertically movable molding table 83, and above the resin tank 81 is provided a light beam 85 irradiation device including an optical system such as a lens 88. When the light beam 85 is applied to the liquid surface of the photocurable resin liquid 82, the photocurable resin liquid from the liquid surface in the vicinity of the focal point of the light beam 85 to a certain thickness
82 is cured to form the photocured layer 90. Since the photo-curing layer 90 is placed on the molding table 83, when the molding table 83 is lowered, the photo-curing layer 90 sinks below the liquid surface and the photo-curing layer 90
The upper part is covered with the uncured photocurable resin liquid 82. afterwards,
When the liquid surface of the photocurable resin liquid 82 is irradiated with the light beam 85 in the same manner as described above, the second photocurable layer 90 is formed. By repeating such formation of the photocurable layer 90 by irradiation of the light beam 85 and supply of new photocurable resin liquid 82 onto the photocurable layer 90 by lowering the molding table 83, a plurality of photocurable resin liquids 82 are formed. Article having a three-dimensional shape in which the photo-curing layer 90 of two layers is laminated
80 is formed.

In the method for forming a three-dimensional shape using a photo-curable resin as described above, in order to improve the shape accuracy of the molded article 80 having a three-dimensional shape, a light beam for forming the photo-curable layer 90.
The penetration depth and movement range of the 85 are accurately controlled using a computer or the like.

[Problems to be solved by the invention]

However, even when the irradiation of the light beam is precisely controlled as described above, when the photocurable resin that is cured by the light beam causes shrinkage deformation during curing, the shape accuracy of the photocured layer that is formed deteriorates, There is a problem that the shape accuracy of a molded product having a three-dimensional shape formed by stacking the photo-curable layers also deteriorates. Further, if the shrinkage stress at the time of curing remains in the photocurable layer as residual stress, there is a problem that the residual stress is gradually released after curing and the photocurable layer or the molded product is deformed with time.

In the conventional three-dimensional shape forming method, in order to improve work efficiency, a light beam having a strong curing action is rapidly moved to irradiate the photocurable resin to rapidly cure the photocurable resin. However, when curing is rapidly performed with a light beam having a strong curing action in this way, the amount of curing contraction increases and residual stress also easily occurs. That is, when the curing is performed slowly, the curing proceeds while the surrounding resin liquid is supplied so as to supplement the curing shrinkage amount during the irradiation of the light beam, so that the curing shrinkage as a whole is small, and the curing Since the shrinkage stress is released during the progress, the occurrence of residual stress is reduced. However, if the curing is rapid, the supply of the resin liquid that compensates for the curing shrinkage amount will not be in time, a large curing shrinkage will remain, and the curing will be completed before the shrinkage stress is released, so residual stress may occur. It becomes. Furthermore, when the photo-cured layer is formed while moving the irradiation position of the light beam, the difference in curing shrinkage between the first cured portion and the later cured portion causes local deformation and uneven distribution of residual stress. As a result, there is a high possibility that locally large distortion or nonuniform residual stress will occur in the formed product.

Therefore, an object of the present invention is to provide a molded product of high quality, which is excellent in shape accuracy, does not deform with time due to residual stress and is not deteriorated in the method for forming a three-dimensional shape using a photocurable resin as described above. It is to provide a method that can be obtained and that has high work efficiency.

[Means for solving the problem]

Among the means of the present invention for achieving the above object, the method for forming a three-dimensional shape according to claim 1 is to irradiate a photocurable resin with light to form a photocurable layer, and to form the photocurable layer. In the method of stacking a plurality of layers to form a desired three-dimensional shape, from the first photo-curable layer cured to the final stage by irradiating light over the entire surface of the photo-curable resin forming the photo-curable layer. The lowermost photocured layer is formed, and the main cured part obtained by curing the photocurable resin to the final stage on the lowermost photocured layer, and the uncured part not irradiated with light or the intermediate stage is cured. A plurality of second photo-curing layers having the semi-cured part formed thereon are stacked, and the first photo-curing layer is formed as the uppermost photo-curing layer forming the three-dimensional shape, and then the three-dimensional shape is formed. To cure the entire uncured or semi-cured part to the final stage It is obtained by a method of forming a three-dimensional shape to symptoms.

Further, the method for forming a three-dimensional shape according to claim 2 is characterized in that a part of the second photo-curable layer forming the three-dimensional shape is replaced with the first photo-curable layer. The method for forming a three-dimensional shape is as described in the first item of the above range.

[Action]

According to the first and second aspects of the invention, the lowermost layer and the uppermost layer of the photocurable layer are the first photocurable layer which is cured to the final stage by irradiating the entire surface of the photocurable resin with light. Since it consists of a three-dimensional skeleton or outer shell, it is formed between them and the main cured part where the photo-curable resin is cured to the final stage and the uncured part that does not irradiate light or the intermediate stage is cured. It is possible to prevent the uncured portion or the semi-cured portion of the second photo-cured layer having the formed semi-cured portion from flowing out or collapsing before being cured to the final stage. Further, replacing a part of the second photo-curable layer constituting the three-dimensional shape of the claim 2 with the first photo-curable layer is carried out in order to make the skeleton of the three-dimensional shape stronger. It is a thing.

The uncured portion or the semi-cured portion that does not cure the photocurable resin can move or deform the resin, and can absorb the deformation and shrinkage stress due to the curing shrinkage of the main cured portion. Therefore, first, if the main cured part of the skeleton or outer shell of the three-dimensional shape is formed by slow curing, the three-dimensional shape can be accurately formed and the partial main cured part cures. The shrinkage amount and the shrinkage stress are relatively small, and can be absorbed by the uncured portion or the semi-cured portion. After that, when curing the uncured part or the semi-cured part to the final stage, by uniformly irradiating the whole with light, good quality and slow curing can be achieved, and the photocurable resin can be locally applied to the final stage at a time. The curing shrinkage is much smaller than that of curing it. In addition, there is little influence on the main cured portion that has already been cured. Therefore, the finally formed three-dimensional shape has high shape accuracy and there is no fear of time-dependent deformation or reduction in strength due to residual stress. That is, by not hardening the entire three-dimensional shape at once, but hardening a part of the three-dimensional shape uniformly from an uncured or semi-cured state, it is possible to suppress hardening shrinkage and release shrinkage stress.

〔Example〕

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 12 is a diagram showing the overall configuration of an apparatus for forming a three-dimensional shape of the present invention, and FIG. 13 is a sectional view of the resin liquid tank 11 thereof. The device is a photocurable resin liquid 12
It is provided with a resin liquid tank 11 for storing, a vertically movable lifting arm 13 for vertically moving the formed photo-curing layer 14, and an optical system. The optical system generates a light beam 15, for example, a light beam generator 10 such as a He-Cd laser generator, a shutter 19 for the light beam 15, a liquid surface of the photocurable resin liquid 12 in the resin liquid tank 11 It is provided with a condenser lens 18 for focusing on and mirrors 16, 17 for scanning the light beam 15 in the X-axis and Y-axis directions.

In the method for forming a three-dimensional shape of the present invention using the apparatus as described above, first, the forming table 21 of the elevating arm 13 is raised to near the liquid surface, and the liquid surface is irradiated with the light beam 15 in a predetermined shape to be photocured. The resin solution 12 is cured to form the first-layer photocurable layer 14. After that, the process of lowering the elevating arm 13 to cure the photocurable resin liquid 12 between the first-layer photocurable layer 14 and the liquid surface to form the next-layer photocurable layer 14, is repeated, A molded article (20) having a three-dimensional shape in which a plurality of photocurable layers (14) are stacked is formed.

However, in the conventional method of forming a three-dimensional shape, when the photocurable resin liquid is irradiated with a light beam, the curing is completed up to the final stage.
As shown in FIG. 1 and below, it has a second photo-curing layer 34 in which a main curing portion 34A that is cured to the final stage as in the conventional case and an uncured portion 34B that is not irradiated with the light beam 15 are separately formed. It is what

FIG. 1 and FIG. 2 show the irradiation pattern of the light beam 15 in the method for forming a three-dimensional shape according to the present invention. That is, a three-dimensional shape is formed into a plurality of photo-curing layers (4 in FIG. 1).
(The case of a layer is shown as an example), and the lowermost layer (first layer) and the uppermost layer (fourth layer) are the first photocured layer 24 composed of a main cured portion irradiated with the light beam 15 on the entire surface, and the inner layer portion. In the second layer and the third layer, the outermost shell is irradiated with the light beam 15 to form the main curing portion 34A, and then the inside thereof is not irradiated with the light beam 15 and the uncured portion 34B and the light beam 15 are not irradiated. The second photo-curable layer 34 having the main cured portion 34A is formed. As shown in FIG. 1A, when the spot diameter of one irradiation is set to d, the first photo-curable layer 24 has the following irradiation and irradiation parts. The irradiation spot diameter and irradiation pitch are determined so that they overlap by a width t and irradiation is performed. Also second
As shown in FIG. (A), the light beam 15 is irradiated to the outermost shells of the lowermost layer and the uppermost layer of the photocurable resin in such a setting,
After that, the light beam 15 is radiated into the interior of the first light-curing layer 24 so that the first light-curing layer 24 is fully cured.

Hereinafter, examples of division patterns of the second photo-curable layer 34 forming the main cured portion 34A and the uncured portion 34B of the inner layer portion will be described.

FIG. 2 (b) shows a method of forming a divided pattern, which is formed by a pattern of an irradiated portion and a non-irradiated portion that are substantially similar to the outer shell shape of the layer. Similarly, FIG. 3 is formed by the irradiation and non-irradiation patterns that are substantially similar to each other. However, by forming a sharp irradiation pattern by reducing the irradiation spot diameter in at least a part thereof, a similar shape can be obtained. It corresponds to the part that cannot be done. Further, FIG. 4 shows a case where the second photo-curable layer 34 is formed by drawing scanning lines in a radial or potential streamline shape from the central portion when the scanning line spacing is large.

FIG. 5 shows a method of forming a division pattern for the inner layer portion when the three-dimensional shape has a cavity 72 therein. That is, the outer shell 73 and the inner shell 74 are irradiated with a light beam so as to form a closed loop to form a main cured portion, and the uncured portion 34B and the main cured portion 34A are formed between the closed loops to form the second light. The hardened layer 34 is used. When the cavity reaches the lowermost layer or the uppermost layer, the outer shell portion and the inner shell portion are similarly irradiated with the light beam 15 so as to form a closed loop to form a main cured portion, and a gap is formed between the closed loops. Instead, a scanning line is drawn to form a first photo-cured layer, which is entirely hard-cured. FIG. 5 (a) is a view showing a cross section of a three-dimensional shape.

Figure 6 shows. By the method of forming the divided pattern of the inner layer, the outer shell and the inner shell are irradiated with a light beam so as to form a closed loop to form a main cured portion, and a honeycomb-shaped light beam scan is performed between the closed loops to form a second light beam. The hardened layer 34 is formed.

FIG. 7 shows a method of forming a second photo-curing layer 34 by forming an outer shell portion as a method of forming a divided pattern of the inner layer portion, and then performing concentric light beam scanning around the center of gravity of the cross-sectional shape, for example. is there. Similarly, FIG. 8 shows a case where the spiral light beam scanning is performed to form the second photo-curable layer 34. Furthermore,
FIG. 9 shows that the second photo-curable layer 34 is formed by further performing radial scanning in addition to the concentric circular light beam scanning shown in FIG.

Figure 10 shows. After forming the outer shell as a method of forming the divided pattern of the inner layer, in forming the partial main curing portion in the closed loop of the outer shell, the light per irradiation area in the irradiation portion of the light beam for curing the photocurable resin is By changing the irradiation amount partially, a dumpling-like portion is formed on a part of the scanning line. As a method of partially changing the light irradiation amount per irradiation area, in raster scanning, the scanning speed is changed by slowing the speed in the dumpling-like part and increasing it in the straight part, and entering the light beam with a shutter etc. It is possible to turn it on / off, change the focal position of the light beam 15, and the like.

Further, as shown in FIG. 11 (FIG. 11 exemplifies a case where the photo-cured layer is composed of 5 layers), a part of the second photo-cured layer 34 of the inner layer constituting the molded article 20 having a three-dimensional shape is formed. By substituting the first photo-curable layer 24, the skeleton of the three-dimensional molded article 20 can be made stronger. The embodiment shown in FIG. 11 shows an example in which the second photocurable layer 34 is replaced with the first photocurable layer 24 in the middle layer.

Incidentally, the uncured portion 34B forming the second photo-curable layer 34 in these examples is replaced with a semi-cured portion obtained by curing the photo-curable resin halfway while irradiating the light beam only halfway. Can also achieve the purpose.

After forming the three-dimensional shape by these methods, the three-dimensional shape is completed by curing the uncured portion of the entire three-dimensional shape to the final stage. In the curing up to the final step, it is possible to irradiate light from four directions so that the entire three-dimensional shape is simultaneously and uniformly cured, or to irradiate light while rotating the three-dimensional shape. If this is done, it will be a short-time cure as a whole, but a slower cure will be possible in a partial view.

〔The invention's effect〕

According to the method for forming a three-dimensional shape in claims 1 and 2 of the present invention described above, a photo-curable resin is applied to the inner photo-curable layer forming the three-dimensional shape. After forming a main cured part that has been cured to the final stage and an uncured part that does not irradiate light or a semi-cured part that has been cured to a mid-stage, the uncured part or semi-cured part of the entire three-dimensional shape is evenly finalized Since it is cured up to, it is possible to absorb the curing shrinkage and shrinkage stress caused by curing the photocurable resin of the main cured part which is the skeleton in the uncured part or the semi-cured part, and the uncured part or the semi-cured part. When the parts are uniformly hardened to the final stage, the hardening shrinkage and shrinkage stress generated by hardening are small, and the hardening shrinkage of the uncured or semi-hardened part is suppressed by the already hardened part, so the entire three-dimensional shape The curing shrinkage of Lost command, does not cause a reduction in strength or cause worry little over time variant residual stress remains.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a three-dimensional shape formed by the method of the present invention for each photo-curing layer, a light beam irradiation diagram and a longitudinal sectional view of the curing layer, and FIG. 2 is a formation of the three-dimensional shape of the present invention. Scanning pattern diagrams for irradiating a light beam on the first photo-curing layer and the second photo-curing layer, showing examples of the method, FIGS.
FIG. 10 is a pattern diagram showing different second photocurable layer division pattern examples, and FIG. 11 is a three-dimensional configuration and first and second photocurable layer examples showing different examples of the present invention. Perspective view, FIG. 12 is an overall configuration diagram of an apparatus for forming a three-dimensional shape of the present invention, FIG. 13 is a sectional view of the resin liquid tank,
FIG. 14 is a schematic configuration diagram showing a conventional example. 10 …… Light beam generator, 11 …… Resin liquid tank 12 …… Light curable resin liquid, 14 …… Molded product, 15 …… Light beam, 16,17 …… Mirror, 18 …… Lens, 24 …… First photo-curing layer, 34 …… Second photo-curing layer, 34A …… Main curing part, 34B
...... Unhardened part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shungo Ozawa 1048 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Works Co., Ltd. (72) Yoshiyuki Uchino, 1048 Kadoma, Kadoma City, Osaka Matsushita Electric Works Co., Ltd. (72) Inventor Yoshizen Higashi 1048, Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Works Co., Ltd. (56) Reference JP-A-2-24123 (JP, A) JP-A-2-111528 (JP, A) Japanese Patent Laid-Open No. 2-24124 (JP, A)

Claims (2)

(57) [Claims] 1. A method of forming a photocurable layer by irradiating a photocurable resin with light to form a photocurable layer and stacking a plurality of the photocurable layers to form a desired three-dimensional shape, wherein the photocurable layer is formed. Form the lowermost photocurable layer consisting of the first photocurable layer cured by irradiating the entire surface of the photocurable resin with light, and the photocurable layer on the lowermost photocurable layer. A plurality of second photo-cured layers, each of which has a main cured part obtained by curing the resin to the final stage and an uncured part not exposed to light or a semi-cured part cured to an intermediate stage, are laminated to form the three-dimensional shape. After forming the first photo-curable layer as the uppermost photo-curable layer constituting the three-dimensional shape characterized by curing the uncured portion or semi-cured portion of the entire three-dimensional shape to the final stage Method. 2. The method for forming a three-dimensional shape according to claim 1, wherein a part of the second photo-curable layer forming the three-dimensional shape is replaced with the first photo-curable layer.