Characteristics of investment casting method

Characteristics of investment casting method  

1. It can cast complex castings of all kinds of alloys, especially high temperature alloy castings.  For example, the blade of jet engine, its streamlined outer profile and cooling inner cavity, with machining process almost impossible to form.  Investment casting process can not only achieve mass production, ensure the consistency of castings, but also avoid the stress concentration of residual blade lines after machining.  

2. The dimensional accuracy of investment casting is high, generally up to CT4-6 (ct10~13 for sand casting and CT5 ~7 for die casting). Of course, due to the complex process of investment casting, there are many factors affecting the dimensional accuracy of casting.  Such as shrinkage, deformation of investment casting mould materials, shell in the process of heating and cooling line quantity change, alloy of shrinkage and deformation of the casting during solidification, etc., so ordinary size although higher precision investment castings, but still need to improve the consistency (in medium and high temperature of the wax casting size consistency to improve a lot).  

3. When pressing the investment die, the pressure type with high surface finish of the cavity is used. Therefore, the surface finish of the investment die is relatively high.  In addition, the shell is made of high temperature resistant special binder and refractory material prepared refractory coating coated on the investment mold and made of high surface finish in direct contact with the molten metal cavity.  Therefore, the surface finish of investment casting is higher than that of general casting parts, generally up to Ra.1.6 ~3.2μm.  

4. The biggest advantage of investment casting is that because investment casting has a high dimensional accuracy and surface finish, mechanical processing can be reduced, only a little processing allowance can be left in the parts requiring higher parts, and even some castings only leave grinding and polishing allowance, without mechanical processing can be used.  It can be seen that the investment casting method can greatly save machine tools, processing time and metal raw materials.