Precision casting is a metal die casting process performed on a die casting machine. It is currently the most efficient casting process. Die casting machines can be divided into two categories: hot chamber die casting machines and cold chamber die casting machines. The hot-chamber die-casting machine has a high degree of automation, the material loss is small, and the production efficiency is much improved compared to the cold-chamber die-casting machine. However, the hot-chamber die-casting machine is restricted by its heat resistance and can only be used for castings of metals with low melting points, such as zinc alloys and magnesium alloys. At present, aluminum alloy die castings, which are widely used, can only be produced on cold chamber die casting machines due to the high melting point of aluminum alloy. The main feature of precision casting is that the metal hydraulic pressure fills the cavity under high pressure and high speed, and forms and solidifies under high pressure.
The disadvantage of die-casting parts is that during the process of filling the cavity with molten metal at high pressure and high speed, the air in the cavity is inevitably entrapped inside the casting to form subcutaneous pores. Therefore, aluminum alloy precision die-casting parts are not suitable for heat treatment. Zinc alloy die castings are not suitable for surface spraying (but painting can be done). Otherwise, when the pores inside the casting are heated for the above treatment, they will expand when exposed to heat and cause the casting to be deformed or bubbling. In addition, the machining allowance of die-casting parts should also be smaller, generally around 0.5mm, which can reduce the weight of the casting and reduce the amount of cutting to reduce the cost. It can also avoid penetrating the dense layer of the surface and exposing the subcutaneous pores. The artifact is scrapped.