What is vacuum precision casting
Vacuum casting is a casting process in which metals are melted, poured and crystallized in a vacuum chamber. Vacuum casting can minimize the gas content in metal and prevent metal oxidation and trachoma. The casting with high requirements can be produced by this method. The cost of vacuum casting is high, so it is usually used for high quality castings, and the mold should not contain volatiles.
Vacuum casting is a casting method in which the mold gate (or riser) is inserted into the molten metal, and then the mold is vacuumed to make the mold cavity negative pressure. Under the negative pressure, the molten metal rises along the gate (or riser) and fills the mold and solidifies to form a casting method.
The process principle of vacuum casting is to put the investment mold in the sealing chamber, the sealing chamber drops, the sprue is immersed in the liquid metal, and then the vacuum pump is started to pump the sealing chamber into vacuum, and the liquid is cast at the same time. After solidification, the vacuum state of the castings in the mold shell is relieved, and the residual metal liquid in the runner flows back to the furnace, and the vacuum casting casting casting is obtained by sand cleaning.
The characteristics of vacuum precision casting are as follows
(1) High yield, good quality of casting, smooth filling of liquid metal, less oxide slag inclusion and splash, reducing porosity and slag inclusion and other defects, and improving the yield. In addition, the lower pouring temperature can be used to refine the grain size and improve the mechanical properties.
(2) Good filling performance. When casting, the back pressure in the mold cavity is small and the filling speed is adjustable, so the filling ability is strong, and the thinnest part of the casting can reach 0.3 mm.
(3) The utilization rate and process yield of molten metal are greatly improved.
(4) Simplify the process and reduce the cost.
(5) It is easy to realize mechanization and has high labor productivity. Compared with the conventional investment casting process, each module can assemble more wax patterns, and the output can be increased by 85% - 135%.