JPH04366619A - Optical shaping method - Google Patents

Abstract

PURPOSE:To prevent generation of a distorsion on a shaped body by low freedom of contraction of a contacting surface between base and the first cured layer, in a method where a target form body is shaped by laminating in order the cured layers by repeating a process in which the cured layer is formed on a base by applying a beam to photosetting resin, the base is moved at a fixed pitch, after the cured layer is covered with the photosetting resin, the beam is applied to the same. CONSTITUTION:A pedestal layer 10, which is contraction-deformable in the direction of a base face is provided between a base 21 and a cured layer 24a. With this construction, curing and contraction in the direction of the base face are allowed by a pedestal layer 10 and a distortionless shaped body is obtained. It does not happen that a cured matter is peeled off from a base in the middle of shaping.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention 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 beam of light.

0002

[Prior Art] A light beam is irradiated onto a photocurable resin to cure the irradiated portion, and this cured portion is continued horizontally, 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 JP-A No. 60-247515, 6.
It is publicly known from No. 2-35966, No. 62-101408, etc. It is also known to use a mask instead of scanning the beam.

This type of optical modeling method includes a container containing a photocurable resin, a device for irradiating light into the container,
Some have a base that is movable within the container. This optical modeling method will be explained with reference to FIG.

In FIG. 3, a photocurable resin 12 is contained in a container 11. As shown in FIG. A transparent window 13 made of a transparent plate such as quartz glass is provided on the bottom of the container 11.
The light emitting part 15 with a built-in lens, the optical fiber 16, and the light emitting part 15 are moved in the X-Y direction (X, Y are two orthogonal directions) in a horizontal plane so as to irradiate the light beam 14 toward the transparent window 13. X-Y moving device 17 and optical shutter 18 to move the
, 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 moving device 17 and elevator 22 are controlled by a computer 23.

When producing a cured body using the above-mentioned apparatus, first, the base 21 is positioned slightly above the light-transmitting window 13, and the light beam 14 is scanned along the horizontal cross section of the object. This scanning is carried out by a computer-controlled X-Y moving device 1.
7.

[0007] After irradiating the entire horizontal cross section of the target shape (in this case, the portion corresponding to the bottom or top surface), the base 21 is raised by a predetermined pitch, and the cured layer 24
After flowing an uncured photocurable resin between the light-transmitting window 13 and the light-transmitting window 13, the same light irradiation as described above is performed. By repeating this procedure, a cured body (shaped body) having the desired shape is obtained as a multilayer laminate.

In contrast to the method shown in FIG. 3 in which the luminous flux 14 is irradiated from the bottom side of the container 11, a method is also known in which the luminous flux 14 is irradiated from above the liquid level of the photocurable resin. In this method, as shown in FIG. 4, a photocurable resin is interposed between the base 21 or the cured layer 24 on it and the liquid surface 12a to a predetermined thickness, and then a light beam 14 is irradiated to form the desired shape. After forming the hardened layer 24 on one horizontal section of the object, the base 21 is lowered by a predetermined pitch, and other operations are the same as those in FIG. 3.

A method is also known in which the light beam is scanned by tilting a mirror that reflects the light from the light source toward the modeling section, instead of moving the light emitting section 15 in the X-Y direction.

0010

[Problems to be Solved by the Invention] In the conventional method described above, depending on the shape of the object to be formed, distortion may occur due to curing shrinkage of the photocurable resin, resulting in poor dimensional accuracy and shape accuracy of the object. In some cases, the base and the cured product in the middle of modeling may peel off, disrupting the modeling accuracy, and in severe cases, it may become impossible to continue modeling.

That is, due to the contraction of the photocurable resin during curing, the cured layer laminated on the base tends to shrink, but the cured layer that adheres to the base, that is, the first cured layer (hereinafter referred to as , this hardened layer is called the "first layer", and the hardened layers that are sequentially laminated after the first layer are called the "second layer" and the "third layer".
Sometimes referred to as "layer"... ), the base adhesive side is
Restricted by the base, which is a rigid body, it is not possible to sufficiently contract in the direction of the base surface. Due to the insufficient shrinkage of the first layer in the direction of the base surface, there is a difference in shrinkage in the direction of the base surface among the first layer, second layer, third layer, and even higher layers. Distortion occurs in the modeled object. In this case, if the shrinkage stress is greater than the adhesive strength between the first layer and the base, the first layer and the base will separate.

[0012] Such a phenomenon occurs frequently especially when solid objects that undergo large curing shrinkage are to be modeled. Further, even if the shaped body is hollow or lattice-like or contour shaped, if the size thereof is large, the above phenomenon occurs because the shrinkage due to hardening is large.

The present invention solves the above-mentioned conventional problems, prevents the occurrence of distortion due to shrinkage of the cured layer, and prevents separation of the cured product from the base during modeling, thereby producing a shaped object having a desired shape with high precision. The purpose is to provide an optical modeling method that allows for

[0014]

[Means for Solving the Problems] The optical modeling method of the present invention provides a movable base in a container, and hardens the photocurable resin housed in the container by scanning and irradiating it with light. A layer is formed on the base, and then the base is moved at a predetermined pitch to cover the cured layer with a photocurable resin, and then light is irradiated. By repeating this process, the cured layers are sequentially laminated to form the desired shape. In the optical modeling method, a pedestal layer that can be contracted and deformed in the direction of the base surface is provided between the first hardened layer of the target-shaped body and the base, and the target-shaped body is modeled on the pedestal layer. This is characterized in that curing and shrinkage of the target shaped body in the direction of the base surface is allowed.

[0015]

[Operation] In the optical modeling method of the present invention, the first
The pedestal layer provided between the layer and the base acts as a stress relaxation layer, thereby allowing curing shrinkage of the first layer, the second layer, or more in the direction of the base surface. That is,
Since the pedestal layer is capable of shrinking and deforming in the direction of the base surface, the first layer (or the second or higher cured layer) can be cured and shrunk in the direction of the base surface relatively freely. Therefore, the generation of shrinkage differences between the cured layers is prevented, and uniform curing and shrinkage over the entire shaped body results in a distortion-free shaped body.

[0016]

[Embodiment] An embodiment will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a base portion showing an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line 1--2 in FIG.

In the method of this embodiment, as the base layer 10,
Solid first pedestal layer 10A and grid-like second pedestal layer 10
Modeling is performed with B interposed between the base 21 and the first layer 24a.

The second pedestal layer 10B has a square lattice-like horizontal cross section and is elastically deformable in the direction of the base surface.

The first pedestal layer 10A is a solid portion, and the first pedestal layer 10A has a large adhesive area between the base 21 and the pedestal layer 10, so that the bond between the base 21 and the pedestal layer 10 is increased. Improves adhesive strength. Note that the second pedestal layer 1
If sufficient adhesion between 0B and the base can be secured,
The first pedestal layer 10A may be omitted. Alternatively, the aperture ratio of the lattice in the cross section on the base surface side of the second pedestal layer 10B may be reduced.

In this embodiment, the effect of improving the adhesive strength to the base by the first pedestal layer 10A and the effect of the second pedestal layer 10B
In order to fully obtain the effect of relieving shrinkage stress due to
The dimensions of each part in FIG. 2 are preferably as follows. Note that in the following, the cross-sectional area refers to the cross-sectional area of a plane parallel to the base surface.

Pedestal layer cross-sectional area: Approximately 1 to 2 times the cross-sectional area of the hardened layer Length L and width W: 1 to √2 of the hardened layer length and width, respectively
Double first pedestal layer thickness d1: n1 x PZ mm, n1
=2~5 Second pedestal layer thickness d2: n2 × PZ mm
, n2 = 10-25, second pedestal layer Z-direction lattice pitch PZ = 0.1-0.
4mm Second pedestal layer X, lattice pitch in Y direction PX, PY =
Approximately 0.5 to 3 mm Cross-sectional area Am of the second pedestal layer excluding the lattice openings: A/Am≦1.5-3 with respect to the cross-sectional area A of the hardened layer
The pedestal layer shown in the figures and FIG. 2 is an example of the pedestal layer according to the present invention, and the pedestal layer of other shapes,
For example, an overall grid-like pedestal layer 30 as shown in FIG. 5 can be employed. It goes without saying that the opening of the pedestal is not limited to a square shape, but can also be circular, hexagonal, or the like.

Although the method of the present invention is effective for forming shaped objects that undergo large shrinkage due to curing, generally, the shaped objects for which the present invention is effective in preventing distortion due to curing shrinkage are as follows: It is as follows. ■ A solid object with a simple shape. For example, one side is about 30mm
The above rectangular bodies ■ Hollow or lattice shaped bodies or contour shaped bodies. For example, the pedestal layer used in the present invention is a rectangular body with a side of about 150 mm or more.
It is also possible to use a product manufactured by injection molding or cutting, and glue it to the base.
First, the pedestal layer portion may be formed using an optical modeling method.

[0023] Such an optical modeling method of the present invention is based on the third
It is possible to apply not only to the optical shaping apparatus shown in the figures and FIG. 4 but also to any optical shaping apparatus. In addition to the XY moving device, a tilting mirror can also be used to scan the light beam. Instead of scanning the light beam, a mask may be used to irradiate the light.

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

[0025] As the light, various types of light such as visible light and ultraviolet light can be used depending on the photocurable resin used. The light may be normal light, but by using laser light, the energy level can be increased and the molding time can be shortened.
It is possible to obtain the advantage that modeling accuracy can be improved by utilizing good light convergence.

[0026]

Effects of the Invention As detailed above, according to the optical modeling method of the present invention, the curing shrinkage in the direction of the base surface of the cured layer is equalized over the entire modeled object, resulting in distortion-free dimensional accuracy and shape accuracy. An excellent shaped object is manufactured. Furthermore, peeling of the cured product from the base during modeling due to uneven curing shrinkage is also prevented.

[Brief explanation of drawings]

FIG. 1 is an enlarged cross-sectional view of essential parts showing one embodiment of the present invention.

2] FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1.

FIG. 3 is a sectional view of an optical shaping device applicable to the present invention.

FIG. 4 is a sectional view of an optical shaping device applicable to the present invention.

FIG. 5 is a perspective view showing another example of the pedestal layer.

[Explanation of symbols]

10 Pedestal layer 10A First pedestal layer 10B Second pedestal layer 12 Photocurable resin 13 Translucent window 14 Luminous flux 15 Light output part 16 Optical fiber 20 Light source 21 Base 22 Elevator 24 Hardened layer

Claims (1)

[Claims] Claim 1: A movable base is provided in a container, a cured layer is formed on the base by scanning and irradiating the photocurable resin housed in the container with light, and then the base is moved at a predetermined pitch. In an optical modeling method in which the cured layer is covered with a photocurable resin, the cured layer is covered with a photocurable resin, and the process is repeated to sequentially stack the cured layers to form a target shape. A pedestal layer that can be contracted and deformed in the direction of the base surface is provided between the first hardened layer and the base,
An optical modeling method characterized in that by forming the target shape on the pedestal layer, curing and shrinkage of the target shape in the direction of the base surface is allowed.