The essence of die casting (referred to as die c […]
The essence of die casting (referred to as die casting) is a method of filling the die-casting mold cavity with liquid or semi-liquid metal at a high speed under the action of high pressure, and forming and solidifying under pressure to obtain castings.
High-pressure and high-speed filling of die-casting molds are the two major characteristics of die-casting. Its commonly used injection specific pressure is from thousands to tens of thousands of kPa, or even as high as 2×. The filling speed is about 10~/s, and sometimes it can even reach above/s. The filling time is very short, generally in the range of 0.01~0.2s. Compared with other casting methods, die casting has the following two advantages:
Good product quality
Castings have high dimensional accuracy, generally equivalent to grade 6~7, or even up to grade 4; good surface finish, generally equivalent to grade 5~8; high strength and hardness, the strength is generally 25~30% higher than that of sand casting, but the extension The rate is reduced by about 70%; the size is stable, and the interchangeability is good; it can die-cast thin-walled and complex castings. For example, the current minimum wall thickness of zinc alloy die castings can reach 0.3mm; aluminum alloy castings can reach 0.5mm; the minimum casting hole diameter is 0.7mm; the minimum pitch is 0.5mm.
The machine has high productivity. For example, the domestic JIII3 horizontal cold air die-casting machine can die-cast ~ times every eight hours on average, and the small hot-chamber die-casting machine can die-cast ~ times every eight hours on average; The lifespan can reach hundreds of thousands of times or even millions of times; it is easy to realize mechanization and automation.