Advantages of investment casting
The dimensional accuracy of investment casting is relatively high, which can generally reach ct4-6 (ct10~13 for sand casting, ct5~7 for die casting). Of course, due to the complexity of the investment casting process, there are many factors affecting the dimensional accuracy of castings, such as mold materials Shrinkage, deformation of investment mold, line amount change during heating and cooling,
The shrinkage rate of the alloy and the deformation of the casting during solidification, so the dimensional accuracy of ordinary investment castings is high, but the consistency still needs to be improved (the dimensional uniformity of high-temperature wax castings in use is much improved). When molding, the surface finish of the mold cavity is high, so the surface finish of the mold is relatively high. In addition, the shell is made of a special adhesive that is resistant to high temperatures and a refractory coating made of refractory materials, with a high surface finish in the cavity that is in direct contact with the molten metal.
Therefore, the surface finish of investment castings is higher than that of general castings, up to ra.1.6~3.2μm. The biggest advantage of investment casting is that the dimensional accuracy and surface finish of investment casting are high, so machining work can be reduced, but some machining allowances should be left for parts with high requirements, and even some castings only leave grinding and polishing allowances. Quantity, can be used without machining.
It can be seen that the investment casting method can save a lot of machine tools and processing time, and greatly save metal raw materials. Another advantage of the investment casting method is that it can be used to cast complex castings of various alloys, especially for casting superalloy castings. For example, the blades of jet engines, with their streamlined outer contours and cooled inner cavities, are difficult to shape with machining processes.
Production by investment casting process can not only realize mass production, ensure the consistency of castings, but also avoid the stress concentration of residual knife lines after machining.
