JPH0318031Y2 - - Google Patents

Description

[Detailed explanation of the idea] (Industrial application field) The present invention relates to a casting model.

(Prior Art) Various types of casting models are used, such as wooden molds, metal molds, and resin molds, all of which have advantages and disadvantages. For example, although wooden molds have the advantage of being inexpensive to manufacture, they have many cellular voids and are made of rough material, making them susceptible to damage such as abrasion from contact with molding sand.
Impossible to use for a long time. The wooden mold is also hygroscopic and expands and contracts, which tends to cause dimensional deviations, resulting in poor dimensional accuracy of the product. On the other hand, molds and resin molds have excellent abrasion resistance and moisture absorption resistance, but have the drawback of increasing production costs. In view of these problems, a casting model has been proposed in which the voids in the wood cells in the surface layer of the wooden pattern are impregnated with a synthetic resin (for example, Utility Model Publication No. 47-27610). However, with this method, the synthetic resin does not sufficiently penetrate into the surface layer parallel to the fiber direction of the wood, which makes it difficult to obtain sufficient abrasion resistance and moisture absorption resistance for wooden molds with complex shapes. I couldn't let him have it.

(Purpose of the invention) The present invention was made in view of the above-mentioned circumstances.A model is molded from paper clay, and the surface layer of the model is impregnated with synthetic resin, thereby making it resistant to wear and moisture absorption. The purpose is to provide a model that has excellent properties and can be manufactured at low cost.

(Structure of the invention) Hereinafter, the invention will be described in detail based on examples. First, a primary model 1 of a rough shape is formed using paper clay as a material, and after drying and hardening this, woodworking is performed. A secondary model (hereinafter referred to as the main body of the model) 3 is obtained by finishing with a cutter 2. (1st
(See Figure and Figure 2).

Second, the model main body 3 is placed in a vacuum container (not shown) with a reduced pressure of 3 mmHg for 1.5 hours to remove air from the porous voids of the model main body 3. Third
Then, a liquid synthetic resin is injected into the reduced pressure container while maintaining the reduced pressure state, and the model main body 3 is injected into the reduced pressure container.
The whole is immersed in the synthetic resin. Fourth, after a predetermined period of time has elapsed, the pressure inside the vacuum container is returned to normal pressure, and the model main body 3 is left immersed in the synthetic resin for about 8 hours.

As a result, the synthetic resin permeates into the voids in the surface layer of the model main body 3. Fifth, the model main body 3 is taken out from the vacuum container and heated at 90° C. for 3 hours. As a result, the synthetic resin that has penetrated into the surface layer of the model main body 3 is cured, and the final model 5 is provided with a wear-resistant and moisture absorption-resistant reinforcing layer 4 on its surface.
is obtained (see Figure 3). In the examples, the entire model is made of paper clay, but if the shape of the model is large, only the necessary parts may be molded with paper clay, and after being impregnated, it may be bonded to the original model.

(Effects of the invention) As is clear from the above explanation, the invention involves molding a primary model from paper clay, applying finishing to it, and impregnating the surface layer with synthetic resin. , a secondary model (mainly model) molded from such materials and subjected to finishing processing
is non-directional porous in nature, and the pores of the material are not aligned in a specific direction, so the synthetic resin reliably spreads over the entire surface layer.
And it penetrates evenly. Therefore, even a model with a complicated shape can be provided with sufficient wear resistance and moisture absorption resistance. In addition, the model of the present invention is cheaper in material cost and easier to process than metal molds and resin molds.

[Brief explanation of the drawing]

1 to 3 are cross-sectional views showing the manufacturing process of the present invention. 1: Primary model, 2: Woodworking cutter, 3: Second
Next model (mainly model), 4: Reinforcement layer, 5: Final model.

Claims (1)

[Scope of utility model registration request] A casting model characterized in that a synthetic resin impregnated reinforcing layer 4 is formed on the surface of a model main body 3 made of paper clay.