1. Theory

Investment casting is a special casting method compared to traditional casting technology. It can obtain relatively accurate shape and high casting precision. The more common method is: first design and manufacture the mold according to the product requirements (with a very small or no allowance). Cast wax by casting method to obtain the original wax pattern; repeat the coating and sanding process on the wax pattern, harden the shell and dry it; then melt the internal wax pattern and obtain the cavity as dewaxing; bake the shell To obtain sufficient strength and air permeability; pour the required metal materials; remove the sand after shelling, so as to obtain high-precision finished products. According to the needs of the product, heat treatment and cold processing are carried out.

2.Advantages

A. Easy production for complex parts: with complex shapes and inner cavities

B. Wide range of application: 1)Casting materials areunlimited. It’sthe only molding process for materials with poor plasticity (such as cast iron, etc.).2)The size and wall thickness of castings are almost unlimited.3)Thelargebatch is not limited.

3. Principles of Casting Method Selection

(1) Sand casting is preferred, and wet casting is preferred

(2) The casting method should be compatible with the production batch.

A. Factories that mass-produce castings in large quantities should create conditions to adopt technologically advanced molding and core-making methods.

B. Castings produced in small batches of one piece - heavy castings produced in small batches of one piece. Hand shaping is still an important method. Manual modeling can adapt to various complex requirements and is more flexible, and does not require a lot of process equipment.

C. Special casting low pressure casting, die casting, centrifugal casting and other casting methods. Due to the high price of equipment and molds, it is only suitable for mass production.

(3) The molding method should be suitable for the factory conditions.

(4) Take into account the accuracy requirements and cost of castings.