Design of Investment Casting Process

1、Definition

Investment casting, also known as “lost wax casting”, usually in the wax mold surface coated with several layers of refractory materials, to be hardened and dried after the wax mold melted away and made of shell, and then after baking, and then pouring, and obtain castings of a method, due to the casting has a high degree of dimensional accuracy and surface finish, so it is also known as “melting precision casting”.

2, features

1) casting size accuracy generally up to CT4-6

2) casting complex shape castings, especially casting of high-temperature alloy castings

3) not subject to the limitations of the casting material

4) casting size can not be too large, the weight is also limited

5)The process is complex, many procedures, so that the production process control is much more difficult

6)The casting cooling speed is slow, the casting grain is coarse when pressing the molten mold, using the cavity surface finish of the high pressure type, therefore, the molten surface finish is also relatively high. In addition, the type shell by high temperature resistant special binder and refractory materials formulated into a refractory coating coated in the molten mold and made, and molten metal direct contact cavity surface finish is high. Therefore, the surface finish of the molten casting is higher than that of the general casting.

The biggest advantage of investment casting is that due to the high dimensional accuracy and surface finish of investment casting, so it can reduce the machining work, just leave a little machining allowance in the parts with high requirements, and even some castings only leave grinding and polishing allowance, no need for machining can be used. It can be seen that the use of investment casting method can save a lot of machine tool equipment and processing time, substantial savings in metal raw materials.