JPS6232009A - Method for forming solid shape - Google Patents

Abstract

PURPOSE:To make it possible to easily form a solid shape with high accuracy, by successively photocuring resin layers with two-layered constitution consisting of an least two kinds of liquid photocurable resin materials different in a photocuring threshold value in a laminated form by using an exposure means comprising laser beam having an exposure energy value proper to said resin materials. CONSTITUTION:At first, a sub-scanning stand 41 is adjusted by raising and falling operation in a vertical direction so that the surface of a first resin layer 21 to be cured by exposure comes to the focal position of laser beam 39. Next, not only the sub-scanning stand 41 is sent at a constant feed speed to start sub-scanning but also the supply of a liquid photocurable resin material B having a required photocuring threshold value in a resin material receiving container 40 from a resin material supply port 42a in a thickness of 250mum is started and, from the point of time when the sub-scanning start 41 moved over an interval l1 or more, the supply of a liquid photocurable resin material A having a characteristic larger in a photocuring threshold value than that of the resin material B onto the resin layer B in the resin material receiving container 40 in a thickness of 250mum from the other resin material supply port 43a is newly started. Thereafter, from the point of time when the sub-scanning stand 41 moved over an interval l2, the irradiation of laser beam 39 is applied to the surface of the first resin layer 21 as main scanning on the basis of the solid shape pattern of the first layer to selectively expose and cure the same.

Description

[Detailed Description of the Invention] [Summary] The present invention selectively exposes and scans a three-dimensional shape that displays three-dimensional stereoscopic information each time a liquid photocurable resin material is supplied in layers. In the method of forming the photocurable resin layer in a laminated form, each supplied resin layer of the liquid photocurable resin material is laminated with at least two types of liquid photocurable resin materials having different photocuring threshold characteristics. When the next resin layer supplied on the resin layer that has already been selectively cured by exposure scanning is exposed and scanned, the exposure light affects the selectively cured resin layer below. By controlling the effect of , the deformation of the shape at the boundary portion of each photocurable resin layer is eliminated, and a highly accurate three-dimensional cured resin shape is formed.

[Industrial application field]

The present invention is a method for forming a three-dimensional model shape that displays three-dimensional stereoscopic information by repeating the process of selectively exposing and curing a liquid photocurable resin material using an exposure scanning means of a laser beam optical system in the stacking direction. In particular, the present invention relates to a method of forming a highly accurate three-dimensional cured resin shape without deterioration of the shape at the boundary portion of each photocurable resin layer formed in a laminated manner.

As methods for displaying three-dimensional stereoscopic information, perspective view display, projection view display, contour line display, stereoscopic display using holography, etc. have been developed and are generally widely used. However, none of these methods are necessarily satisfactory for intuitively grasping and fully understanding the displayed three-dimensional shape, and they also create and display non-existent three-dimensional virtual objects, three-dimensional bird fin diagrams, etc. That is not easy.

For this reason, in recent years, in order to intuitively grasp 3D information and display it in an easy-to-understand manner, methods for relatively easily forming model-like 3D shapes have been developed, such as using photocurable resin and laser beam optical systems. It has been proposed to selectively photocure the photocurable resin based on three-dimensional information using an exposure scanning means to form a complex three-dimensional model shape in a layered manner.

By the way, in such a formation method, the step of selectively photocuring the photocurable resin based on stereoscopic information is repeated in the laminating direction to form sequentially laminated layers of the selectively photocured resin. At this time, when the next resin layer supplied on the resin layer that has already been selectively photocured is exposed and scanned, the exposure light reaches the lower selectively cured resin layer and causes a collision with the lower photocurable resin layer. There is a problem in that the photocured shape at the boundary portion deteriorates, making it difficult to obtain a highly accurate three-dimensionally cured resin shape, and there is a demand for improvement of this problem.

(Prior art) Conventionally, in order to form a model shape that displays three-dimensional stereoscopic information using a photocurable resin and an exposure means using laser beam irradiation, first, as shown in FIG. In a resin material storage container 1 placed on a sub-scanning table 2, a liquid photocurable resin material is placed in a first part corresponding to the thickness of the three-dimensional model shape to be created divided into several slices. At the same time, the sub-scanning table 2 is finely adjusted in the vertical direction so that the surface of the supplied resin material 5 becomes the focal point of the irradiated laser beam 4.

Next, as shown in FIG. 4(b), the surface of the resin material 5 is scanned and reflected by the laser beam optical system based on a three-dimensional shape pattern signal obtained by dividing the three-dimensional model shape to be created into several slices. The reflected laser beam 4 or the sub-scanning table 2 is moved and scanned in the X and Y directions to perform laser beam irradiation, thereby forming a first cured resin layer 5a that is selectively cured by exposure.

Next, as shown in FIG. 4(C), the liquid photocurable resin material 6 for the second layer is supplied, and the surface of the supplied resin material 6 is adjusted again so that it becomes the focal point of the irradiated laser beam 4. , after finely adjusting the sub-scanning table 2 in the vertical direction, as shown in Fig. 4(d).
As shown in , the surface of the resin material 6 is similarly irradiated with a laser beam based on the three-dimensional pattern signal to form a second cured resin layer 6a that is selectively cured by exposure.

Thereafter, as shown in FIG. 4+13), the liquid photocurable resin material 7 for the second layer is selectively exposed and cured by the same process to form a third cured resin layer 7a. A laminated three-dimensional cured resin image is formed in the liquid photocurable resin material.

By taking out this three-dimensional cured resin image from the liquid photocurable resin material and washing away the attached liquid photocurable resin material with a cleaning solution or the like, the desired image can be obtained as shown in FIG. 4(f). A three-dimensional model shape 8 for displaying three-dimensional three-dimensional information is created.

[Problem that the invention seeks to solve]

However, in the conventional method of forming a three-dimensional shape using an exposure means using laser beam irradiation as described above,
Each liquid photocurable resin layer5. 6. Since the laser beam 4 irradiated onto the resin layer passes through the resin layer while its light energy is absorbed in the depth direction, the value of the exposure energy generally changes as shown in FIG. It has a characteristic of continuously attenuating in the depth direction of the mold resin layers 5 and 6.

In addition, since the liquid photocurable resin layer has the property of being photocured only in the area where exposure energy exceeding the curing darkness value of the liquid photocurable resin material is applied, for example, it has already been selectively cured. When selectively exposing the second liquid photocurable resin layer 6 that has been supplied and formed on the first photocurable resin layer 5a that has been exposed and cured, the liquid photocurable resin layer 6 of the second layer is It is possible to selectively expose and cure only the mold resin layer 6 and precisely control so that exposure energy exceeding the curing darkness value of the resin material does not reach the first photocurable resin layer 58 directly below it. It was difficult.

For this reason, when the output of the laser beam used for exposure changes, the cured thickness of the exposed and cured resin layer changes significantly, which poses a drawback that becomes a major hindrance in forming a highly accurate three-dimensional shape.

In view of these conventional drawbacks, the present invention uses at least two types of liquid photocurable resin materials with different curing threshold characteristics to eliminate deformation of the shape of the cured resin at the boundary portion of each successively laminated resin layer. It is an object of the present invention to provide a novel method for forming a three-dimensional shape that makes it possible to easily form a three-dimensional shape with high precision.

[Means for solving problems]

In order to achieve the above object, the present invention includes laminating at least two types of liquid photocurable resin layers having different curing threshold characteristics in each liquid photocurable resin layer for forming a three-dimensional cured resin shape in a layered manner. When the two-layered liquid photocurable resin layer is exposed to light using a laser beam or the like having a light energy that is approximately an intermediate value between the curing dark values of the two layers, the upper resin layer having different curing threshold characteristics is exposed to light. It utilizes the phenomenon that the lower resin layer remains uncured while the resin layer is cured.

That is, the curing threshold Eth of a liquid photocurable resin material is expressed by the following (Equation 11), where α is the light absorption coefficient, t is the resin curing thickness (resin supply thickness), and Ee is the exposure energy. .

Eth = Ee −exp (−αt) ・・
・fl) Therefore, as shown in Fig. 1, the light absorption coefficient αA
.

A liquid photocurable resin layer A having a resin supply thickness tA having a curing threshold value EthA, a light absorption coefficient αB, and a curing darkness value EthB.

and a liquid photocurable resin layer B having a resin supply thickness tB, and a resin supply thickness LA having a light absorption coefficient α^ and a curing threshold ELhA in the same way.
Liquid photocurable resin layer A, light absorption coefficient αB, and curing darkness value E
thB, and a liquid photocurable resin layer B having a resin supply thickness tB. When exposing and curing only 22, the exposure energies E2A, E2B, and EIA reaching the lower surface portions of the second resin layer 22A, the second resin layer 22B, and the first resin layer 21A are (2), (3), respectively. It is expressed by equation (4).

E28 -Ee -exp (-8 -tA)
・ ・ ・ (2) [2B = Ee
-exp (-(A-tA+ B-tB)) ・
13) EIA = Ee-exp (-(2A -t
A+B-tB) ) 14) Also, in equations (2) to (4), the conditions under which the second resin layer 22 is completely photocured are expressed by the following equation.

E2A > f! thA, EthB...(
5) E2B > EthB...(6)
Furthermore, at this time, the following relational expression is important as a condition for not photocuring the first resin layer 21.

E2B <ll+thA...(7)
EIA < EthB (8) [Function] Therefore, various characteristics α of the liquid photocurable resin layers A and B that constitute the first resin layer 21 and the second resin layer 22.

By exposing and curing the second resin layer 22 on the first resin layer 21, the second resin layer 22 on the first resin layer 21 is cured by setting Eth, resin supply thickness tA, etc., and exposure energy He to satisfy the above formulas (5) to (8). - Due to the difference in darkness value in the layer boundary region between the resin layer 21 and the second resin layer 22 and the attenuation phenomenon of the exposure energy He, the second resin layer 22 can be used without affecting the first resin layer 21.
It becomes possible to photocure only the

If a laminated three-dimensional cured resin shape is formed by such a forming method, a highly accurate three-dimensional cured resin shape that does not deform in the layer boundary region even if the output of exposure light changes somewhat can be obtained.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 2 is a schematic perspective view showing an embodiment of a forming apparatus used in the method for forming a three-dimensional shape according to the present invention.

In the figure, 31 is a laser device, 32 is an optical modulator, and 33 is a laser device.
is a reflecting mirror, 34.35 is a lens, 36 is a rotating polygon mirror, 3
7 is an fθ lens, and 38 is a scanning reflector, which constitute a laser beam optical system.

Further, 40 is a resin material storage container in which a liquid photocurable resin material 44 is stored, and the storage container 40 moves and scans in the direction of arrow A, and also has a sub-scanning table that can be raised and lowered in the vertical direction shown by arrow B. It is placed on 41.

Further, on the resin material storage container 40, there are elongated supply ports 42a and 43a for supplying two types of liquid photocurable resin materials A and B having different light absorption coefficients α and photocuring threshold values Eth into the storage container 40, respectively. two resin supply pipes 42.4 with
3 are arranged.

A laser beam 39 emitted from the laser device 31 is modulated by an optical modulator 32, reflected by a reflecting mirror 33, converted to an appropriate beam diameter by lenses 34 and 35, and deflected by a rotating polygon mirror 36. Ru. Furthermore, it is scanned at a constant speed by the fθ lens 37, and the scanning reflector 38
The liquid photocurable resin material 44 in the resin material storage container 40 is
The surface of the resin is irradiated and selectively exposed and cured to form a photocurable resin layer.

Now, in order to form a three-dimensional model shape that displays three-dimensional three-dimensional information using such a forming apparatus, the method shown in FIG. 3 (al.
The supply ports 42 of the two resin supply pipes 42 and 43 as shown in
Assuming that the distance between a and 43a is 'l+the distance between the supply port 42a and the main scanning position of the laser beam 39 is 22, the surface of the first resin layer 21 to be exposed and hardened first is at the focus position of the laser beam 39. The sub-scanning table 41 is vertically moved up and down to adjust the position.

Next, the sub-scanning table 41 starts sub-scanning at a constant speed, and the resin material storage container 40 is opened from the resin material supply port 42a.
For example, the light absorption coefficient α is 18 cm −1 and the photocuring threshold E
The liquid photocurable resin material B having a thin characteristic of 14 mJ/cm2 is started to be supplied to a layer thickness of 250 μm, and from the time when the sub-scanning table 41 is moved to a distance of 11 or more, the other resin material is newly added. For example, the light absorption coefficient α is 6 cm −1 + the light curing threshold E thA is 211 from the supply port 43 a onto the resin layer B in the resin material storage container 40 .
Supply of liquid photocurable resin material A having a characteristic of 1 IJ/Cm2 to a layer thickness of 250 μm is started.

After that, the sub-scanning table 41 is moved at intervals as shown in Fig. 3).
! From the point at which the three-dimensional model shape to be created is divided into several slices, the thickness of which is 500μ in this case.
A three-dimensional shape pattern signal of the first layer obtained by dividing the three-dimensional model shape to be created into several slices on the surface of the first resin layer 21 consisting of the resin layer B and resin layer A corresponding to m). The first cured resin layer 21a is formed by selectively exposing and curing the resin by main-scanning the laser beam 39 based on the above.

Note that the exposure energy Ee of the laser beam 39 at this time is determined by the following equation (5) based on the relationships of equations (5) to (8) above.
)' to (8) are necessary conditions.

Ee〉25IIIJ/cI112, 17IIIJ/cI
112...(5)'Ee > 25mJ/ca+2.
...(6) 'Ee<3811IJ/c112...(
7) Ee < 29n+J/cta2...(8)
``Therefore, the light absorption coefficient α of the above two types of resin layers A and B
, a photocuring threshold IEth, a layer thickness, etc., are set to an exposure energy value Ee in the range shown by the following equation.

25+wJ/cs+2<Ee<29sJ/cm2H+
+ (9) When the resin material supply port 42a reaches the other end of the resin storage container 40, the supply of all the resin materials A and B is stopped, and then the second resin layer 22 to be cured by exposure is Adjust the sub-scanning table 41 by vertically raising and lowering it so that the surface is at the focal point of the laser beam 39, and as shown in FIG. 3(C), move the resin material storage container 40 back to its original position. Immediately return to the sub-scanning start position.

Next, as shown in FIG. 3(d), the sub-scanning table 41 starts sub-scanning at a constant speed, and the resin material supply port 42
As in the case of the first resin layer 21, two liquid photocurable resin materials B and A are placed in the resin material storage container 40 from a and 43a.
The supply is started sequentially to the layer thickness of the 50 μm pot, and a second layer is applied to the surface of the second resin layer 22 consisting of the resin layer B and the resin layer A, in which the three-dimensional model shape to be created is divided into several slices. The first cured resin layer 21 is formed based on the three-dimensional shape pattern signal of the layer.
The second cured resin layer 22a is formed by selectively exposing and curing the second cured resin layer 22a by main-scanning irradiation with a laser beam 39 having the same exposure energy value Ee as in forming a.

Thereafter, after stopping the supply of the +n resin material and adjusting the focal position of the next laser beam 39 by the same process operation, as shown in Fig. 3 (el
As shown in , the resin material storage container 40 is quickly returned to the original sub-scanning start position using the sub-scanning table 41, and the above steps are repeated to sequentially form exposed and cured resin layers to form a layered three-dimensional cured resin image. To construct.

In such a laminated three-dimensional hardened resin image, resin layers A and B have a two-layer structure with different light absorption coefficient α and light hardening threshold Eth.
Using the exposure energy value Ee that satisfies the above equation (9)
When the next resin layer on the resin layer formed by the previous exposure operation is selectively exposed and cured by the exposure operation of the laser beam 39 having Since only the next resin layer is selectively exposed and cured, shape changes due to cross-boundary curing at these layer boundary areas are eliminated.

Therefore, the desired three-dimensional stereoscopic information can be obtained by removing the laminated three-dimensional cured resin image from the liquid photocurable resin material and removing the liquid photocurable resin material in the same manner as in the past. It becomes possible to obtain the three-dimensional cured resin shape to be displayed with high precision.

〔Effect of the invention〕

As is clear from the above explanation, according to the method for forming a three-dimensional shape according to the present invention, at least two
A resin layer with a two-layer structure consisting of various types of liquid photocurable resin materials and an appropriate exposure energy value t'e for these resin materials.
By sequentially photo-curing the resin layers in a laminated form using an exposure means consisting of a laser beam having a This has the excellent advantage that a highly accurate three-dimensional shape can be easily formed in a relatively short time, which is only the time required for setting the surface position of each resin layer and for exposure scanning.

[Brief explanation of drawings]

1 is a diagram for explaining the principle of the three-dimensional shape forming method according to the present invention; 1 FIG. 2 is a schematic configuration diagram showing an embodiment of a forming apparatus used in the three-dimensional shape forming method according to the present invention; FIG. 3 is a cross-sectional view of a main part showing an example of the method for forming a three-dimensional shape according to the present invention in the order of steps; FIG. 4 is a cross-sectional view of a main part for explaining a conventional method for forming a three-dimensional shape; FIG. FIG. 2 is a diagram showing the distribution of exposure energy in the depth direction of the resin layer. In FIGS. 1 to 3, A and B are liquid photocurable resin layers having different photocuring threshold characteristics;
21 is a first resin layer, 21a is a first cured resin layer, 22 is a second resin layer, 22a is a second cured resin layer, 31 is a laser device, 32 is an optical modulator, 36 is a rotating polygon mirror, 37 is fθ 38 is a scanning reflector, 39 is a laser beam, 40 is a resin material storage container, 41 is a sub-scanning table, 42 and 43 are resin material supply pipes, 42a and 43a are 1st II Shrimp cover 1 ellipse 2nd figure LvJ

Claims (1)

[Claims] Each time the liquid photocurable resin material is supplied in a laminated form, exposure is scanned to selectively cure each resin layer (21, 22), thereby forming the photocurable resin layer (21a, 22a) in a laminated form. In the method for forming a three-dimensional shape, each supply resin layer (21, 22) of the liquid photocurable resin material is replaced with at least two types of liquid photocurable resin materials (A, B) having different photocuring threshold characteristics.
is a layered unit layer, and when the next unit resin layer (22) supplied on the unit resin layer (21a) which has already been exposed and scanned and selectively cured is exposed and scanned, the exposure light is A method for forming a three-dimensional shape, characterized in that the effect of the selectively cured resin layer (21a) on the selectively cured resin layer (21a) is controlled.