Advantages of investment casting

24-07-2019

The size accuracy of investment casting is high, generally up to ct4-6 (sand casting CT10~13, die casting CT5~7).Of course, due to the complex investment casting process, there are many factors that affect the precision of casting size, such as mold.The shrinkage of materials, the deformation of the melt, the change in the amount of shell during heating and cooling, the shrinkage of the alloy, and the deformation of the casting during solidification, etc., therefore, the size accuracy of the ordinary melt casting is higher, but the consistency still needs to be improved (the size uniformity of the casting using medium and high temperature wax is much higher).

熔模铸件的优点

熔模铸件的优点

When pressing the mold, the use of high-altitude cavity surface smoothness of the mold products, therefore, the investment mold surface smoothness is relatively high.In addition, the shell is made of a refractory coating, which is made of a special adhesive and a refractory material resistant to high temperature, and is applied to the investment mold, and the inner surface of the mold cavity is in direct contact with the molten metal with a high surface finish.Therefore, the surface finish of molten casting is higher than that of ordinary casting, generally reaching Ra.

The biggest advantage of investment casting is that, due to the high dimensional accuracy and surface finish of investment casting, it can reduce machining work, but only a small amount of machining allowance is needed on parts, and even some castings only have grinding and polishing allowance, and 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 investment casting is that it can cast complex castings of various alloys, especially high temperature alloy castings.The blades of a jet engine, for example, have a streamlined profile and cooling chamber that can hardly be machined.The production of investment casting can not only realize mass production, but also ensure the consistency of casting and avoid the stress concentration of residual cutting tools.

The first step in investment casting production is the manufacture of investment molds.The investment mould is used to form a cavity in the refractory shell.Therefore, in order to obtain castings with high dimensional accuracy and surface finish, the first die itself should have a high dimension.Precision and surface finish.In addition, the properties of the investment die itself should be as simple as possible in order to subsequently form the shell process.In order to obtain the above high quality investment, in addition to the good pressure type (used to press the mold mold), also need to choose the appropriate molding materials (called molding materials) and reasonable molding process.