Die casting is a kind of metal mold pressure casting on die casting machine, which is the current casting process. Die casting machine is divided into hot chamber die casting machine and cold chamber die casting machine. The hot chamber die casting machine has the advantages of high automation, less material loss and higher production efficiency than the cold chamber die casting machine. However, restricted by the heat resistance of the parts, it can only be used in the casting production of low melting point materials such as zinc alloy and magnesium alloy. Because of the high melting point, die casting parts widely used nowadays can only be produced on cold chamber die casting machine.

The main feature of die casting is that the liquid metal fills the mold cavity under high pressure and high speed, and forms and solidifies under high pressure. The disadvantage of die casting is that the air in the cavity is inevitably wrapped in the inner part of the casting to form subcutaneous blowholes during the filling process of liquid metal under high pressure and high speed. Therefore, the die casting parts are not suitable for heat treatment, and the surface of die castings is not suitable for plastic spraying (but can be sprayed) Paint). Otherwise, the air hole in the casting will expand with heat and cause deformation or bubbling. In addition, the machining allowance of die casting parts should be smaller, generally about 0.5mm, which can not only reduce the casting weight, reduce the cutting amount and reduce the cost, but also avoid penetrating the surface dense layer and exposing the subcutaneous pores, resulting in the scrapping of the workpiece.

Die casting is a process in which the metal is melted into the required liquid and poured into the mold. After cooling, solidification and cleaning, the castings with predetermined shape, size and performance can be obtained. Because the casting blank is nearly formed, it can achieve the purpose of no machining or a small amount of processing, which reduces the cost and reduces the production time to a certain extent. Casting is one of the basic technologies in modern device manufacturing industry.