Advantages Of Investment Casting

Investment casting has high dimensional accuracy, generally up to CT4-6 (sand casting for CT10~13, die casting for CT5~7), of course, due to the complex process of investment casting, there are many factors affecting the dimensional accuracy of castings, such as the shrinkage of the mold, the deformation of the investment casting, the change of the line amount of the shell in the heating and cooling process, the shrinkage rate of the alloy and the deformation of the casting during the solidification process, etc., so the dimensional accuracy of ordinary investment castings is high, but its consistency still needs to be improved (the use of medium and The dimensional consistency of castings of high-temperature waxes is much improved).
When pressing the investment mold, the pressing profile with a high surface finish of the cavity is used, so the surface finish of the investment is also relatively high. In addition, the shell is made of a refractory coating made of a special binder and refractory material that is resistant to high temperatures and is applied to the investment mold, and the inner surface of the cavity in direct contact with the molten metal has a high finish. Therefore, the surface finish of investment castings is higher than that of general castings, generally up to Ra.1.6~3.2μm.
The biggest advantage of investment casting is that because investment casting has high dimensional accuracy and surface finish, it can reduce machining work, just leave a little processing allowance in the parts with higher requirements, and even some castings only leave grinding and polishing margin, which can be used without machining. It can be seen that the use of investment casting method can greatly save machine tool equipment and processing hours, and greatly save metal raw materials.
Another advantage of the investment casting method is that it can cast complex castings of various alloys, especially superalloy castings. For example, the blades of jet engines, their streamlined outline and cooling cavity can hardly be formed by machining. The production by investment casting process can not only achieve mass production, ensure the consistency of castings, but also avoid the stress concentration of residual knife patterns after machining.