JPS6380940A - Manufacture of master mold - Google Patents

Abstract

PURPOSE:To maintain high dimensional accuracy and to easily manufacture a master mold by forming a model having the same shape as the shape of the master mold to be used as a drag, sticking a flexible material to the surface to form a negative mold and packing a pattern material into the negative mold, thereby manufacturing the master mold to be used as the cope. CONSTITUTION:The model 1 is formed by working wood and is the master mold A to be used as the drag. The flexible member 2 having the same thickness as the wall thickness of a casting is stuck to the surface of the model 1 to form a model B. The resin is poured to the outside of the model B to form the negative mold C. The resin which is the pattern material is poured into the negative mold C and is solidified to complete the manufacture of the master mold D to be used as the cope. The improvement in dimensional accuracy and the reduction of the cost of production are thereby attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a main mold for molding a mold without using a core.

[Prior Art and Problems to be Solved by the Invention] The material of the main mold for molding a mold is appropriately selected from metal molds, wooden molds, resin molds, etc., depending on the number of molds to be manufactured.

In general, it is desirable for castings to have a uniform wall thickness so that the molten metal drips well, prevents potash casting defects from occurring, and does not add unnecessary thickness to the casting. In many cases, this wall thickness is determined by the dimensional difference between the main mold and the core, but when molding a mold that does not use a core, the wall thickness is determined by the dimensional difference between the upper mold and the lower mold. It is decided.

If the wall thickness of the casting is relatively large, this is not a big problem, but as the mechanical properties of castings have improved significantly in recent years, and the weight and thickness of castings have been reduced, the dimensional accuracy of the upper and lower molds has become more important. Improvements are now strictly required.

The upper and lower molds are manufactured separately based on the drawings, so if the shapes of the upper and lower molds are relatively simple, the dimensional accuracy of the casting wall thickness can be maintained, but the curved surface In many complex thin-walled castings, it is extremely difficult to perfectly match the shapes of the upper and lower molds while maintaining a constant wall thickness difference.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a main mold that maintains a high level of dimensional accuracy in the upper and lower molds of a thin-walled casting having a complex shape and that can be manufactured easily.

[Means for solving problems]

The main mold manufacturing method of the present invention is that when manufacturing a main mold for manufacturing a mold that does not use a core, a model with the same shape as the main mold that will be the lower mold is created and used as the main mold A. Create a model B by pasting a flexible member with a desired thickness on the surface of the model, create a negative mold C of the model B, fill the negative mold C with model material, and solidify it to form the main mold that will become the upper mold. It is characterized by the production of ri.

〔Example〕

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

The figure shows the manufacturing process.

Model 1 is made of wood and is the main mold A which is the lower mold.
A flexible member 2 (hereinafter referred to as sheet wax: trade name) having the same thickness as the casting is attached to the surface of this model 1 to create model B.

Next, resin is injected into the outside of this model B and a negative mold C is created.
A resin, which is a model material, is injected into this negative mold C and solidified to complete the production of the main mold that will become the upper mold.

In the embodiment, wood was used for model 1, but the material is not limited to this, and it is of course possible to use urethane, styrofoam, or other materials with good machinability.

As is clear from the above explanation, 1 the present invention first creates a model 1 having the same shape as the main mold A which is the lower mold, and this model 1
Create a model B by pasting sheet wax 2 with the same thickness as the thickness of the casting on the surface of the mold.Resin is injected to the outside of this model B to create a negative mold C, and the model is placed in this negative mold C. The main mold, which will become the upper mold, is manufactured by filling and solidifying the material.

〔Effect of the invention〕

Therefore, even non-skilled workers can easily operate the
Furthermore, the main mold that will serve as the lower mold and the main mold that will serve as the upper mold can perfectly match their shapes while maintaining the difference in wall thickness of the casting, which has a remarkable effect on improving dimensional accuracy and reducing manufacturing costs. It is something.

[Brief explanation of the drawing]

The expletive diagram is an explanatory diagram of the manufacturing process.

Claims (1)

[Claims] When manufacturing a main mold for manufacturing a mold that does not use a core, a model with the same shape as the main mold that will be the lower mold is created and used as main mold A, and a flexible plate of the desired thickness is attached to the surface of the model. A main mold characterized in that a model B is created by pasting parts, a negative mold C of the model B is created, and a main mold D serving as an upper mold is manufactured by filling and solidifying model material into the negative mold C. How to make a mold.