JPH0224126A - Optical shaping method - Google Patents

Abstract

PURPOSE:To constitute the titled method so that a crack is prevented by preventing shrinkage as a whole of a cured body and generation of a distortion or stress by offsetting shrinkage force at the time of curing by containing photofoaming substance into photosetting resin. CONSTITUTION:A base 21 is made elevatable by an elevator 22 by mounting the base 21 within a vessel 11 and an X-Y shifting device 17 and the elevator 22 are controlled by a computer 23. Photosetting resin 12 containing photofoaming substance is held within a vessel, to begin with, the base 21 is positioned slightly upward than a light transmission window 13 and light flux 14 is scanned after a horizontal section of a target-shaped matter, in manufacture of a cured body. After irradiation with light, uncured photosetting resin containing photofoaming substance is caused to flow into a space between the base and a cured matter 24 by raising the base slightly, similar irradiation with light is performed and this procedure is repeated. With this construction, the photofoaming substance generates small bubbles at the time of the irradiation with light, expansion force is imparted to a cured part of the photosetting resin, a distortion or a crack is prevented by reducing or offsetting curing and shrinkage and formal accuracy is made favorable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an optical modeling method for producing a cured product having a desired shape by irradiating a photocurable resin with a light beam. The present invention also relates to an optical modeling method for producing a three-dimensional model by irradiating light onto a photocurable resin discharged from a nozzle to cure the resin and stacking the resin.

[Prior art] A photocurable resin is irradiated with a light beam to cure the irradiated portion, and this cured portion is continued in the horizontal direction, and a photocurable resin is further supplied above it and cured in the same manner. An optical modeling method in which the cured body is made to continue in the vertical direction by repeating this process to produce a cured body in the desired shape is disclosed in Japanese Patent Application Laid-open Nos. 60-247515 and 62-35966.
No. 62-101408. It is also known to use a mask instead of scanning the beam.

In addition, the photocurable resin is flowed out from the tip of the nozzle, the resin is hardened by irradiating the flowed resin with light, and the nozzle is moved along the cross section of the three-dimensional model to stack the cured resin. Methods for manufacturing three-dimensional models have also been developed in recent years.

[Problems to be Solved by the Invention] Since photocurable resins shrink by about 5 to 20% during curing, distortions and cracks are likely to occur in the three-dimensional objects created by the above-mentioned conventional method. Furthermore, the dimensional accuracy of this three-dimensional object was also poor.

[Means for Solving the Problems] The optical modeling method of the present invention is characterized in that a photocurable resin contains a photofoamable substance that foams when irradiated with light.

[Function] In the present invention, since the photocurable resin contains a photofoamable substance, this photofoamable substance generates small bubbles when irradiated with light and applies expansion force to the cured portion of the photocurable resin. Give. This expansion force offsets the shrinkage force of the photocurable resin during curing, thereby preventing the cured product from shrinking as a whole, preventing strain and stress from occurring, and preventing cracks and the like.

[Example] FIGS. 1 to 4 are sectional views showing an example of an apparatus for carrying out the first invention.

In the apparatus of FIG. 1, a container 11 equipped with an agitator 10
A photocurable resin 12 containing a photofoamable substance is housed inside. A light transmitting window 13 made of a light transmitting plate such as glass is provided on the bottom of the container 11, and a light emitting section 15 with a built-in lens and an optical fiber 16. Moving the light emitting unit 15 in the X-Y direction (X and Y are two orthogonal directions) in the horizontal plane x
- An optical system consisting of a yg shift device 17, a light source 20, etc. is provided.

A base 21 is installed inside the container 11, and the base 21 can be raised and lowered by an elevator 22. These X
-Y moving device 17, elevator 22 is computer 23
controlled by

When producing a cured body using the above device, first the base 21
is positioned slightly below the transparent window 13, and the light beam 14 is scanned along the horizontal cross section of the target object. This scanning is performed by a computer-controlled X-Y movement device 17.

After irradiating the entire horizontal cross section of the target shape (in this case, the part corresponding to the bottom or top surface), the base 2
1 is slightly raised to flow an uncured photocurable resin containing a photofoamable substance between the cured product 24 and the base 21, and then the same light irradiation as above is performed. By repeating this procedure, a cured product having the desired shape can be obtained as a multilayer laminate.

In the above embodiment, a transparent window is provided on the bottom of the container so that light is irradiated from below the container, but in the present invention, a transparent window is provided on the side of the container 11, and light is emitted from the side of the container 11. It is also possible to irradiate. In this case, the base may be gradually moved laterally during the molding process.

In the above embodiment, the light is scanned by moving the optical fiber in the X-Y direction, but as shown in Figure 3 below, the light from the light source is reflected by a mirror and then converged by a lens. An optical system that irradiates the photocurable resin may also be used. In this case, the light beam can be scanned by rotating the mirror.

Further, the present invention may be applied to a known mask method, and a mask 26 having a slit 25 corresponding to the cross section of the target shape may be used, for example, as shown in FIG. Reference numeral 27 indicates a parallel light beam, and other reference numerals in FIG. 2 indicate the same members as in FIG. 1.

The apparatus shown in FIGS. 1 and 2 is configured to irradiate light from below the container, but in the present invention, light may be irradiated from the upper opening of the container.
The apparatus shown in the figures and FIG. 4 is of a type that irradiates light from above the container.

In the apparatus shown in FIG. 3, the liquid level 12 of the photocurable resin 12 is
An optical system including a lens 28, a mirror 29, a mirror rotation drive device 29a, a light source 20, etc. is provided so as to irradiate the light beam 14 toward the direction a. The base 21 is inside the container 11.
is installed, and the base 21 can be raised and lowered by an elevator 22. These driving devices 29a1 and elevators 22 are controlled by a computer 23.

When producing a cured body using the above device, first the base 21
The upper substrate 21a is positioned slightly below the liquid level 12a, and the light beam 14 is scanned along the horizontal cross section of the target object. This scanning is accomplished by computer-controlled mirror 290 rotation.

After irradiating the entire horizontal cross section of the target shape (in this case, the part corresponding to the bottom surface), the base 21 is lowered slightly, and an uncured material containing a photovoltaic material is placed on the cured material 24. After the photocurable resin is introduced, the same light irradiation as above is performed. By repeating this procedure, a cured product having the desired shape can be obtained.

In the above embodiment, the base 21 is gradually lowered, but the liquid level 12a may be gradually raised by pouring more curable resin.

The apparatus shown in FIG. 4 uses a mask 26 having a slit 25 corresponding to the cross section of the object. Reference numeral 2f indicates a parallel light beam, and other reference numerals in FIG. 4 indicate the same members as in FIG. 3.

FIG. 5 is a perspective view illustrating the second method of the present invention. Reference numerals 30 and 31 are storage tanks for storing uncured photocurable resin and photovoltaic material, respectively, and metering feeders 32.3
The photocurable resin and the photovoltaic substance can be supplied to the mixing tank through the tank.

This mixing tank 34 is equipped with an agitator 35. The mixing tank 3
4 is connected to a nozzle 38 via a pipe 36 and a pump 37, and a photocurable resin containing a photofoamable substance can be supplied to the nozzle 38. The nozzle 38 is attached to the tip of a robot arm 40 of a robot device 39, and is movable eight times in each of the X, Y, and Z directions. Note that X, Y%Z indicate orthogonal three-dimensional coordinate axes.

Reference numeral 41 denotes a light source, which is connected to the nozzle 38 via an optical fiber 42 and is capable of irradiating light onto the photocurable resin flowing out from the tip of the nozzle 3B. Reference numeral 43 indicates quantitative feeders 32, 33, pump 37, and robot device 39.
and a computer that controls the light source 41.

Next, a method for manufacturing a three-dimensional model using the apparatus configured as described above will be described.

First, horizontal cross-sectional data of the three-dimensional model 44 to be manufactured is input into the computer 43.

The horizontal cross-sectional data is the shape of a cross-section of the three-dimensional model 44 taken along the horizontal direction so as to perform so-called round slices at each required thickness in the height direction (Z direction). The three-dimensional model 44 in FIG. 1 is a model of a car, and the shape of a cross section 45 having a required thickness near the roof of the car body is one piece of horizontal cross-sectional data. The three-dimensional model 44 as a car model is formed as a stack of many thin cross sections, and the shapes of all the cross sections are input to the computer 43.

Based on the horizontal section data input to the computer 43, the computer 43
control. (Note that the quantitative feeders 32 and 33 are controlled so as to always simultaneously feed materials to the mixing tank 34 at a set rate.) In the embodiment shown in FIG. The upper portion of the tire 47 and the bottom portion of the vehicle body 48 are sequentially formed thereon, and the upper portions are stacked one after another.

When forming a closed loop-shaped cross section indicated by reference numeral 45, the nozzle 38 is moved eight times so as to draw a loop-shaped locus.

The resin flowing out from the nozzle 38 is irradiated with light from a light projection part at the tip of the nozzle 38. As a result, the resin that has flowed out immediately starts to harden and is stacked on the cross section 45 of the model 44 that has already been laminated and hardened to the required hardness.

In the present invention, various substances that are cured by light irradiation can be used as the photocurable resin, such as modified polyurethane methacrylate, oligoester acrylate, urethane acrylate, epoxy acrylate, photosensitive polyimide, and amino alkyd. I can do it.

As the light, various types of light such as visible light and ultraviolet light can be used depending on the photocurable resin used. The illumination may be regular light, but laser light has the advantage of increasing the energy level, shortening the molding time, and improving the molding accuracy by utilizing good light focusing. .

The photofoamable substance is not particularly limited as long as it foams to generate small bubbles when irradiated with light, but photofoamable liquids such as polyvinyl acetate, polystyrene, and saturated polyester are suitable, for example. be. Two or more of these photofoamable substances may be used in combination.

By mixing such a photofoamable substance with a photocurable resin, the shrinkage of the photocurable resin during curing can be offset by the expansion force of small bubbles generated from the photofoamable substance. play. Of course, photofoamable substances also act as fillers and reduce the amount of photocurable resin used, so if they are inexpensive, material costs can be reduced.

The mixing ratio of the photofoamable substance is preferably such that foaming generates an expansion force that can offset the shrinkage force of the photocurable resin during curing and make it almost equal to zero. Although it varies depending on the type of photocurable resin and photofoamable substance used and the curing conditions, the photocurable resin is usually 100! For example, the ratio of 1 to 30 fi parts to i parts, especially 1 to 10! ! It is preferable to add it in parts by weight.

In addition, in the present invention, by using a photofoamable substance, a three-dimensional object that is cloudy due to air bubbles is produced in -a.

[Effects of the Invention] As described above, according to the present invention, curing shrinkage is reduced or offset, distortion and cracking are prevented, and a three-dimensional object with good dimensional accuracy and shape accuracy can be manufactured.

[Brief explanation of the drawing]

1, 2, 3, and 4 are the first embodiments of the present invention, respectively.
FIG. 5 is a sectional view of an apparatus for carrying out the method according to the second invention, and FIG. 5 is a perspective view of the apparatus for carrying out the method according to the second invention. 2... Photocurable resin, 6... Optical fiber part... base, 4... Mixing a, 14... Luminous flux, 20... Light source, 22... Elevator, 38... nozzle.

Claims (2)

[Claims] (1) In an optical modeling method that includes a step of irradiating a photocurable resin with light, curing the portion irradiated with the light, and stacking the cured material, the photocurable resin contains a photofoamable substance. An optical modeling method characterized by (2) Letting the photocurable resin flow out from the tip of the nozzle, and irradiating the resin that has flowed out with light to harden the resin,
and a method for manufacturing a three-dimensional model by moving the nozzle along the cross section of the three-dimensional model and stacking the cured resin, the method comprising using a photocurable resin containing a photofoamable substance. Modeling method.