Precision casting is a casting method relative to the traditional casting process. It can obtain relatively accurate shape and high casting precision. A more common practice is to first make the required blank (can be left with a very small residual or no residual) of the electrode, and then with the electrode corrosion mold specific, forming a cavity. The original wax mould is obtained by casting the wax by casting. Brush the wax mold with high temperature resistant liquid sand. After the sufficient thickness is obtained, dry it and heat it up to melt the wax mold inside, so as to obtain a cavity consistent with the required blank. Cast iron in the mold cavity, solidify after the shell is removed, can be precisely manufactured products.
Wax loss method is now called investment casting, is a less cutting or no cutting casting process, is an excellent casting technology in the casting industry, its application is very wide. It is not only suitable for casting of all kinds of types and alloys, but also can produce castings with higher dimensional accuracy and surface quality than other casting methods.
The application of modern investment casting method in industrial production was in the 1940s. At that time, the development of aerojet engines required the manufacture of heat-resistant alloy parts with complex shapes, precise dimensions and smooth surfaces, such as blades, impellers and nozzles. Due to heat resistant alloy materials difficult to machining, complex shape parts, so that can't or difficult to use other methods, therefore, need to find a new precision forming technology, then draw lessons from the ancient tradition of lost wax casting, after improvement of materials and technology, modern investment casting method on the basis of ancient technology for the development of the important. Therefore, the development of aviation industry promotes the application of investment casting, and the continuous improvement and perfection of investment casting also creates favorable conditions for the aviation industry to further improve the performance.
China began to apply investment casting to industrial production in 1950s and 1960s. Since then, this advanced casting process has been greatly developed, and has been widely used in the manufacturing industries of aviation, automobile, machine tools, ships, internal combustion engines, steam turbines, telecommunications instruments, weapons, medical instruments and cutting tools, etc., as well as in the manufacturing of arts and crafts.
Another advantage of the investment casting method is that it can cast complex castings of various alloys, especially high-temperature alloy castings. For example, the streamlined outer profile and cooling chamber of the blades of a jet engine can hardly be formed by the machining process. Mass production can be achieved by using investment casting process, which guarantees the consistency of casting and avoids the stress concentration of residual cutters after machining.
The sprue cup is the basic component of foundry technology, especially the development of iron and steel industry. Sprue cup is one of the components of smelting equipment.
Sprue cups are mainly used to guide the passage of liquid metal into the cavity. If the pouring cup arrangement is not reasonable, the casting may produce porosity, trachoma, iron bean, slag eye, shrinkage cavity, crack and underpouring defects. Therefore, it is an important task to correctly select the structure and size of the spout cup and to properly place it on the casting.