Die casting is a metal casting process that uses high pressure to rapidly inject liquid or semi-liquid metal into a precise metal mold (Die casting mold), allowing it to solidify and take shape under pressure, thereby obtaining high-precision and well-surfaced castings. The following is a detailed introduction to die casting: Die casting process ■ Mold preparation: Spray lubricant into the mold cavity to control the mold temperature and facilitate the demolding of the casting. ■ Filling: Molten metal is injected into the mold cavity at high pressure and high speed. The pressure is usually between 10 and 175 megapascals. The filling speed is extremely fast, reaching 0.5 to 70m/s, to ensure that the metal fills the entire cavity, including the thin-walled parts. ■ Injection: After filling is completed, continue to maintain the pressure to allow the casting to solidify under pressure. ■ Shakeout: After mold opening, the casting is pushed out through the ejection mechanism, and the excess parts such as the gating system and flash are removed, and the casting is cleaned and trimmed. Die casting type ■ Hot chamber die casting: The injection part is immersed in the liquid metal in the heat-insulating molten crucible. It is suitable for low-melting-point metals such as zinc and magnesium, with high production efficiency, but the injection parts are prone to corrosion. ■ Cold chamber die casting: The metal melting and injection mechanisms are separated. Molten metal is poured into the injection chamber through a spout. It is suitable for high-melting-point metals such as aluminum and copper. The equipment has a longer service life, but the production efficiency is relatively low. Metals for die casting ■ Most die castings are iron-free, such as zinc, copper, aluminium, magnesium, lead, tin, and lead-tin alloys and their alloys.
Advantages and disadvantages: 1. Advantages: High production efficiency, capable of mass-producing small and medium-sized castings, and reducing individual item costs. The castings have high dimensional accuracy, smooth surfaces and good dimensional consistency. It can manufacture castings with complex shapes, reducing subsequent processing. 2. Disadvantages: The cost of molds and equipment is high, making it unsuitable for small-batch production. High-pressure injection may cause defects such as pores inside the castings. Application fields: Widely used in industries such as automobiles, aerospace, electronics, and home appliances, for instance, in manufacturing engine blocks, wheels, transmission cases, and laptop casings for automobiles. Development Trend • With the advancement of technology, large-scale integrated die-casting is gradually becoming a trend. For instance, the Carat920 large-scale integrated die-casting machine launched by Buhler can produce large and integrated automotive parts, enhancing production efficiency and reducing production costs. New die-casting processes are constantly emerging, such as hole-free die-casting, precision die-casting, and semi-solid die-casting, to improve the quality of castings and reduce defects. In conclusion, die casting, as an efficient and precise metal forming process, plays a significant role in modern manufacturing. With the continuous innovation and development of technology, its application prospects will be even broader.
