Features of investment casting:
Another advantage of the investment casting method is that it allows the casting of complex castings of various alloys, especially high temperature alloy castings.For example, the streamlined outer profile and cooling cavity of jet engine blades can hardly be formed by machining process.Mass production can be achieved by using investment casting process, which ensures the consistency of casting and avoids the stress concentration of residual cutting marks after machining.
Size precision investment castings, general of CT4-6 (sand casting is CT10 ~ 13, die-casting is CT5 ~ 7), of course, due to the complexity of investment casting process, factors influencing the dimension accuracy of castings is more, such as mold material shrinkage and deformation of casting, shell in the process of heating and cooling line quantity change, alloy of shrinkage and deformation of castings in the solidification process, so the average 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).
When pressing the investment mold, the pressure mold with high surface finish is adopted. Therefore, the surface finish of the investment mold is also relatively high.In addition, the shell is made of high temperature resistant special binders and refractory materials made of refractory paint coated and hung on the investment mold, and the molten metal in direct contact with the surface finish is high.Therefore, the surface finish of investment casting is higher than that of ordinary casting, which can reach ra.1.6 ~ 3.2m in general.
The biggest advantage of investment casting is that the investment casting has a high dimensional accuracy and surface finish, so it can reduce the machining work, just leave a little machining margin in the parts where higher requirements can be left, and even some castings only leave polishing, polishing margin, can be used without mechanical processing.It can be seen that the investment casting method can save a lot of machine tool equipment and working hours, and greatly save metal raw materials.