JPS63120611A - Method for casting synthetic resin - Google Patents

Abstract

PURPOSE:To prevent a casting mold from deflecting and consequently obtain a cast article with uniform wall thickness by a method wherein synthetic resin liquid is poured in a casting mold under the state that pins having the same length as the wall thickness of the cast article are arranged in the casting mold made of silicone rubber. CONSTITUTION:After a master form made of metal or the like is surrounded by frame plates, liquid silicone rubber is poured in a demain surrounded by the frame plates, and it is hardened at room temperature. After that, the frame plates are removed and the silicone rubber casting mold is divided so as to draw the master form out of it in order to obtain a casting mold. Next, pins 14, which are made of the same synthetic resin material as a cast article, are arranged at proper positions of the casting mold 12. The length L of the pin 14 is made to be equal to the wall thickness of the cast article. After that, two-pack synthetic resin liquid 10 such as epoxy resin or the like is poured in the casting mold 12. After the hardening through the reaction of the liquid, the casting mold 12 is divided so as to remove the cast article from the mold. Since the deflection of the casting mold is prevented from occurring by arranging the pins having the same length as the wall thickness of the cast article in the casting mold, the cast article with a uniform wall thickness can be obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to casting in which a synthetic resin liquid such as a two-component epoxy resin is injected into a mold and cured by reaction, and more specifically, it relates to a casting method in which a synthetic resin liquid such as a two-component epoxy resin is injected into a mold and cured by reaction, and more specifically, it relates to a method for obtaining a uniform wall thickness. Concerning a casting method for.

[Prior art and its problems]

In casting, a mold is made from metal, etc., and then liquid silicone rubber is injected into the mold and cured at room temperature to obtain a mold. Next, a synthetic resin liquid such as epoxy resin is injected into the casting mold and cured by reaction to obtain a cast article.

Silicone rubber is the material for casting molds because it is easy to manufacture molds because accurate molding is performed using a master mold, and silicone rubber has excellent mold releasability and mechanical properties such as tear strength. It is used as.

In a mold with a relatively thin wall thickness and a large flat area,
The casting mold bends due to the weight of the silicone rubber, for example, when the wall thickness is 3.
The cast product i has a problem in that the wall thickness becomes approximately 100% thinner at the center of the plane. This phenomenon occurs regardless of whether the thin wall portion is arranged vertically or horizontally.

An object of the present invention is to provide a casting method that prevents deflection of a casting mold and obtains a uniform wall thickness.

[Means for solving problems]

For the above purpose, in the present invention, a pin having the same length as the wall thickness of the cast product is placed in advance in a casting mold made of silicone rubber, and then a synthetic resin liquid is injected into the casting mold and cast. get goods.

〔Example〕

The present invention will be described in detail below based on the drawings.

FIGS. 1 and 2 are cross-sectional views showing embodiments of the present invention. A prototype is made from a metal material, etc., and after surrounding the prototype with a frame plate, liquid silicone rubber is injected into the frame plate and allowed to harden at room temperature. After that, the frame plate is removed, the silicone rubber casting mold is divided, and the original mold is pulled out to obtain the casting mold.

Next, as shown in FIG. 1, pins 14 made of synthetic resin of the same material as the amount to be cast are placed at appropriate locations on the mold 12.

The length L of the pin 14 is the same as the thickness of the casting amount. Thereafter, a two-component synthetic resin liquid 10 such as an epoxy resin is injected into the casting mold 12, and after reaction and hardening, the casting mold 12 is divided and the cast amount is taken out.

In addition to the shape shown in FIG. 1 with flanges formed on both ends, the pin 14 has the shape shown in FIG. Drum-shaped, Fig. 2 (b
), or make a notch in the center of the pin in Figure 2 (
Possible shapes include forming a flange in the center of the pin in C).

The above example was explained in which the thin parts were placed horizontally, but
Even if the thin walled portion is arranged vertically, deflection of the casting mold can be prevented by placing pins in the casting mold.

〔Effect of the invention〕

As is clear from the above explanation, the bending of the casting mold, which has a relatively thin wall thickness and a large flat area, can be prevented by placing a pin in the casting mold with the same length as the wall thickness of the casting amount. By doing this, it is possible to obtain a casting amount having a uniform thickness.

[Brief explanation of the drawing]

Both Figures 1 and 2 are drawings for explaining the present invention in detail, with Figure 1 being a sectional view showing a state in which pins are placed in a casting mold and casting is performed, Figure 2 ^, b, (This is a cross-sectional view of ゝmy.) 10...Synthetic resin liquid, 12...Casting mold, 14...Pin.

Claims (1)

[Claims] A pin having the same length as the wall thickness of the cast product is placed in a silicone rubber casting mold, and a synthetic resin liquid is injected into the casting mold to prevent the casting mold from warping. A synthetic resin casting method characterized by obtaining the cast article having a uniform wall thickness.