Casting can be divided into gravity casting and pressure casting according to the pouring process of molten metal. Gravity casting refers to the process of injecting molten metal into a mold under the action of the earth's gravity, also called casting. The generalized gravity casting includes sand casting, metal casting, investment casting, mud casting, etc.; the narrow meaning of gravity casting specifically refers to metal casting. Pressure casting refers to the process of injecting molten metal into the mold under the action of other external forces (excluding gravity). In a broad sense, pressure casting includes pressure casting of die casting machine, vacuum casting, low pressure casting, centrifugal casting, etc.; pressure casting in a narrow sense refers to metal die casting of die casting machine, referred to as die casting. These casting processes are currently the most commonly used in non-ferrous metal casting and the lowest relative price.