JPH02111530A - Thermosetting stereolithography method - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a thermosetting stereolithography process that uses hot radiation and a thermosetting fluid material to form a solid body of a desired shape.

Conventional technology and its problems Traditionally, models corresponding to the product shape required during mold production, or models for tracing control in cutting or die-sinking electrical discharge machining electrodes, have been produced by hand processing or using an NC milling machine. This was done by NC cutting using, etc. However, when using manual machining, there is a problem in that it requires a lot of time and skill, and when using NC machining, it is necessary to create a complicated machining program that takes into account exchanges to change the shape of the cutting edge, wear, etc. In addition, there is a problem in that additional finishing machining may be required to remove steps formed on the machined surface.

To solve these problems, the present inventor has proposed the following optical modeling method (Japanese Patent Laid-Open No. 60-24
No. 7515, JP-A-62-101408).

In one embodiment of the method, a photocurable fluid material is housed in a container, and the depth is such that a continuous hardened portion extending over the upper and lower surfaces of the fluid material is obtained by irradiating light from above the container, and selectively irradiate light through a light converging device such as a convex lens to form a hardened portion extending over the upper and lower surfaces of the fluid material, and further irradiate light onto the hardened portion to a depth corresponding to the above depth. Adding a curable fluid material, selectively irradiating the fluid material with light to form a cured portion that extends continuously upward from the cured portion, and adding the photocurable fluid material and forming the cured portion. This process is repeated to form a solid in a desired shape.

According to this optical modeling method, a solid body having a desired shape can be formed with high dimensional accuracy, but the light used in this modeling method needs to be short wavelength light such as ultraviolet light. The short wavelength light is, for example, a helium-cadmium laser (wavelength 325 or less).

Argon laser (wavelength 363.8 nm) etc. can be used, but the short wavelength laser has a low conversion efficiency from electricity to light, so the output of the laser must be low (several mW to several tens of milliwatts). mW output).

For this reason, the curing speed of the photocurable fluid material irradiated with the short wavelength laser is inevitably slow.

Furthermore, since the laser oscillator for irradiating the short wavelength laser is large, the entire system becomes large, and furthermore, the oscillator is expensive and has a short lifespan, so there is a problem that the manufacturing cost for solid-state formation is high.

The purpose of the present invention is to solve the above-mentioned problems and to provide a thermosetting method that can form a solid in a short time, further downsize the entire system, and reduce the manufacturing cost of the solid. The objective is to provide a three-dimensional modeling method.

Means for Solving the Problems The above object of the present invention is to house a thermosetting fluid material that hardens by heat in a container, and while irradiating heat rays into the fluid material, irradiating the heat rays onto the container. On the other hand, this is achieved by a thermosetting three-dimensional modeling method, which is characterized by forming a solid body of a desired shape by relative movement in the horizontal and vertical directions according to the shape of the object to be modeled.

As the thermosetting fluid substance, various substances that are cured by heat irradiation can be used, such as phenol resin, urea resin, melamine resin, unsaturated polyester resin, epoxy resin, silicone resin, polyimide resin, and diallyl phthalate. can be mentioned. In addition, it is preferable that the thermosetting fluid material harden very little at room temperature and have a relatively low viscosity.

As the hot wire, depending on the thermosetting fluid material used,
Infrared rays, heat rays emitted from semiconductor light emitting diodes, etc.
A variety of radiant heat wires and radiant heat wires can be used. By using a heating laser with a high energy level as the heating wire, it is possible to shorten the molding time, and it is possible to obtain the advantage that the molding accuracy can be improved by utilizing good heat collecting property. As the infrared ray, for example, a CO2 laser which is highly efficient in being absorbed by the thermosetting fluid material can be used, and a YAG laser, a semiconductor laser, etc. that emit near infrared rays can also be used. Laser oscillators for infrared irradiation have high energy conversion efficiency from electricity to heat, and even laser oscillators that emit infrared rays of several watts, for example, are small and can be obtained at low cost. When irradiating the thermosetting fluid material with visible light or near-infrared rays that are difficult to absorb heat, it is preferable to add a component capable of promoting heat absorption, such as carbon powder, to the fluid material in advance. When the heat absorption promoting component is added to the thermosetting fluid material, a visible light laser such as an argon laser or a helium-neon laser can also be used as the heating source.

Alternatively, the thermosetting fluid substance may be mixed with a modifying material such as pigment, ceramic powder, metal powder, etc. in advance.

Embodiments Below, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows an example of an apparatus for carrying out the method of the invention. The device consists of a container (1) containing a thermosetting fluid material (A), a base plate (2) supported at the lower end of a vertically extending support rod (3), and a support rod (3). a height control base (4) that can move the base plate (2) vertically; and a position that supports both the container (1) and the height control base (4) and allows them to be moved horizontally and vertically. It is equipped with a control stand (5). Further, the device includes a heat ray source (7) that emits heat rays (L) toward a reflecting mirror (6), and a heat ray (L) that is reflected by the mirror (6).
It is equipped with a heat ray concentrator (8) that converges the fluid material (A) in a dot shape near the upper surface of the fluid material (A) in the container (1), and the fluid material (A) is focused on the heat ray irradiation position based on the movement of the position control table (5). ) can be moved relatively.

In this device, a convex lens and a reflecting mirror (6) were used as the heat ray concentrator (8).
A concave mirror that reflects and converges L) may also be used.

Movement control of the height control table (4) and position control table (5) can be performed as appropriate, such as automatic control such as NC, manual control, etc.

To model a solid in a desired shape using this device, first pour the thermosetting fluid material (A) into the container (1), then lower the support rod (3) to flow the base plate (2). The base plate (2) is immersed in the substance (A) and irradiated with heat rays (L) from above to a depth such that a continuous hardened portion extending from the upper surface of the fluid substance (A) to the upper surface of the base plate (2) is obtained. position. After the positioning, a hot ray (L) with an energy level necessary for curing the fluid material (A) is applied.
) is emitted from a heat ray source (7), and the heat rays (L) are converged into a point shape using a reflecting mirror (6) and a heat ray concentrator (8) and concentrated on the fluid substance (A) on the base plate (2). irradiate. In this state, the container (1) is moved to a location where the heat rays (L) are concentrated, and heat rays are irradiated selectively in accordance with the shape of the shaped solid to be obtained. This allows the fluid substance (A
) A hardened portion can be formed extending from the top surface to the top surface of the base plate (2). Furthermore, on the hardened portion,
Place the base plate (
2) is precipitated in a fluid material (A), and the fluid material (A)
Selective heat ray irradiation is performed from above to form a hardened portion extending continuously upward from the hardened portion, and the settling of the base plate (2) and the formation of the hardened portion are repeated. Thereby, a solid having a desired shape can be formed.

The cured portion (B) shown in FIG. 1 is one in which stepwise curing is repeated during the formation of a solid having the desired shape.

As mentioned above, the heat ray source (7) has high energy conversion efficiency from electricity to heat, and by using high-output heat ray irradiation, the time required for solid formation can be shortened and the running speed based on this can be reduced. Cost reduction can be achieved. Furthermore, even a laser oscillator that emits several watts of heat rays, such as infrared rays, is small in size, and the entire three-dimensional modeling apparatus can be made smaller. Furthermore, such a laser oscillator, even if it is a high output type, can be obtained at a relatively low cost, so it is possible to reduce the equipment cost for forming the solid state.

Experimental Example A Nd:YAG laser oscillator (5L115 type manufactured by NEC ■, wavelength 1.06 μm) was used as a heat ray source. ) was mixed as a heat absorbent in an amount of about 0.5% by weight, and this was used as a thermosetting fluid material. In addition, as a heat ray concentrator, the focal length is 70 mm.
Using a glass convex lens of
．． A 5 mm columnar solid was formed.

In FIG. 2, (α) indicates a non-cured area by the laser irradiation, (β) indicates a locally cured area, and (γ) indicates a wide range cured area.

As a result, the above-mentioned solid formation could be performed about 10 times faster than the above-mentioned optical modeling method.

In such a three-dimensional modeling method, when the fluid material (A) is added onto the hardened portion after first forming a hardened portion based on heat ray irradiation, the downward distance of the base plate (2) is extremely small. Due to the surface tension of the fluid substance (A), the fluid substance (A) may not flow onto the hardened part, and the above-mentioned addition is not reliable. (A) must be introduced. Therefore, the base plate (2) is lowered below the above depth to allow the fluid material (A) to flow onto the hardened portion, and then the base plate (2) is raised to allow the fluid material to flow! (A) If the distance between the upper surface and the upper surface of the hardened portion is set to a distance corresponding to the above-mentioned depth, the fluid substance (A) can be added reliably and no manual labor is required.

Further, the container (1) is configured to overflow the thermosetting fluid material (A) corresponding to the immersion volume increment of the support rod (3) that is lowered to settle the base plate (2).
) Solid formation may be performed while keeping the height of the top surface constant. This has the advantage that it is not necessary to control the movement of the position control table (5) in the vertical direction.

As mentioned above, the method of the present invention is characterized by forming a solid in a desired shape based on heat ray irradiation on a thermosetting fluid material. It is applied to various modeling methods. Therefore, in addition to the modeling method based on heat ray irradiation above the base plate described in the above embodiment, for example, there is a method in which the upper surface of the thermosetting fluid material in the container is slightly raised and a solid is formed by heat ray irradiation from above. It can be applied to a method in which a liquid-tight box-shaped bottomed body having a permeable bottom wall is raised in the fluid material and a solid is formed based on heat ray irradiation from above. Furthermore, part or all of the side wall or bottom wall of the container is made of a material that is transparent to heat rays, a base surface for supporting the cured portion is arranged facing the material, and the base surface is made of a material that is transparent to heat rays. It can also be applied to a method of forming a solid on a substrate surface based on heat ray irradiation through the substance while keeping the substance at a distance.

In the above-mentioned method of adding a thermosetting fluid material onto a hardened part in the solid-state modeling method using a box-shaped bottomed body, the distance to which the bottomed body must be raised is extremely small; It may not be possible to separate the hardened portion, and the reliability of adding the fluid substance is lacking.

For this purpose, the bottomed body is raised above the depth at which a continuous hardened portion is obtained, and the adhesion between the bottom wall of the bottomed body and the hardened portion is peeled off, and then the bottomed body is lowered to connect the lower surface of the bottom wall and the hardened portion. It is preferable that the distance from the upper surface of the portion corresponds to the depth. This also applies to the solid-state modeling method using the above-mentioned base surface. That is, the base surface is moved farther away than the distance that allows a continuous hardened part to be removed, and the adhesion between the hardened part and the heat-transparent material is peeled off, and then the base face is brought closer to the material to reduce the distance between the hardened part surface and the material surface. It is preferable to set it to an appropriate value.

In addition, heat ray irradiation in these methods includes, for example, heat ray irradiation using a thermal conductor, heat ray irradiation in which heat rays emitted from multiple heat ray irradiation sources intersect at one point to form a concentrated high-energy region, and It is possible to employ heat ray irradiation in which high energy portions in a vertical cross section exhibit an annular distribution. By employing heat ray irradiation in which the plurality of heat rays intersect, the thermal energy can be nonlinearly increased at the heat ray irradiation location, and a solid having a desired shape can be quickly formed. Furthermore, if heat ray irradiation with the above-mentioned annular thermal energy distribution is performed, a relatively thick band-shaped solid can be formed with high dimensional accuracy in one scan of the heat ray irradiation, and solids with a desired shape can be formed efficiently. shall be.

In addition, in these above-mentioned modeling methods, in order to prevent deformation of the hardened part during the solid formation process, a reinforcing shape-retaining part is attached to a part where deformation may occur or extends between the part and other parts. It is preferable to perform solid formation while curing and forming at the same time, and to remove the shape-retaining portion as necessary after the formation.

Furthermore, in order to prevent the above deformation, it is also possible to adjust the energy level of the irradiated heat rays according to the moving speed of the heat ray irradiation location, and to perform solid formation while keeping the total amount of heat energy irradiated to the irradiation location substantially constant. .

In addition, in order to facilitate the removal or peeling of the solid from the supporting surface after the solid is formed, a supporting portion having a shape that can be removed after the solid is formed is interposed between the solid having the desired shape and the supporting surface. The support part may be formed based on heat ray irradiation to form the solid, and after the formation, the support part may be removed as necessary, and the support member in a shape that can be removed after the solid formation is used as the solid support surface. The solid state may be formed so as to be supported by the support member, and the support member may be removed as necessary after the formation.

Effects of the Invention As is clear from the above, according to the method of the present invention, the following effects can be obtained.

In other words, the heat ray irradiation point is moved relative to the thermosetting fluid material to form a solid in the desired shape, and the energy necessary for curing is provided by heat, so generally there is a high energy conversion from electricity to heat. An efficient yet small hot wire oscillator can be used. As a result, it is possible to downsize the three-dimensional modeling apparatus capable of forming a solid in the desired shape, and also to form a solid in a desired shape in a short time with high energy conversion efficiency, reducing running costs. Can be placed low. Furthermore, such a laser oscillator, even if it is a high output type, can be obtained at a relatively low cost, so it is possible to reduce the equipment cost for forming the solid state.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an example of an apparatus for carrying out the method of the present invention, and FIG. 2 is a diagram showing the relationship between laser output and feed rate of the laser in a thermosetting three-dimensional modeling method according to an embodiment of the present invention. It is a graph showing a relationship. (1) Container (2) Base plate (7) Heat ray oscillator (A) Thermosetting fluid material (B) ...Hardened part (L) ...Heat wire (above) Fig. L Fig. Laser output (w)

Claims (1)

[Claims] (1) A thermosetting fluid material that hardens with heat is placed in a container, and while heat rays are irradiated into the fluid material, the heat rays are irradiated in horizontal and vertical directions with respect to the container according to the shape of the object to be modeled. A thermosetting three-dimensional modeling method characterized by forming a solid body in a desired shape by relatively moving the solid body.