Die casting is a metal casting process characterized by the use of a mold cavity to apply high pressure to melted metal. Molds are usually made of stronger alloys, in a process somewhat similar to injection molding. Most Die Cast parts are iron-free, such as zinc, copper, aluminum, magnesium, lead, tin, and lead-tin alloys and their alloys. Depending on the type of die casting, either cold chamber die casting or hot chamber die casting is required. The cost of casting equipment and molds is high, so the die casting process is generally only used to produce large quantities of products in bulk. Manufacturing die cast parts is relatively easy, typically requiring only four major steps and with very low incremental cost. Die casting is particularly suitable for the manufacture of large numbers of small and medium-sized castings, so die casting is the most widely used of various casting processes. Compared with other casting techniques, the surface of die casting is more flat and has higher dimensional consistency.
In 1964, the Japanese Die Casting Association defined die casting as "a casting method in which molten alloy is pressed into a precision mold at high temperature to produce a large amount of high precision and a good surface in a short time". The United States called die casting Die Casting, the United Kingdom called die casting Pressure Die Casting, and the most familiar to the domestic general industry is the Japanese term, called die casting. The casting made by Die casting is called Die Cast Part. The tensile strength of these materials is nearly twice as high as that of ordinary cast alloys, which has a more positive significance for aluminum alloy automotive wheels, frames and other components that want to be produced with higher strength impact resistant materials.
Hot chamber die casting, sometimes called gooseneck die casting, consists of pools of molten liquid and semi-liquid metals that are pressed to fill the mold. At the beginning of the cycle, the piston of the machine is contracted, and the molten metal can fill the goose's neck. The pneumatic or hydraulic piston squeezes the metal and fills it into the mold. Advantages of the system include fast cycles (about 15 per minute), easy automation, and easy melting of the metal. Disadvantages include the inability to die cast metals with higher melting points, as well as aluminum, which can draw iron out of the molten pool. Thus, hot - chamber die - casting machines are commonly used for zinc, tin, and lead alloys. Also, hot chamber Die casting is difficult to use for Die casting large die Cast parts, usually this process is die casting small die Cast parts. Cold chamber die casting can be used for metals that cannot be used in the hot chamber die casting process, including aluminum, magnesium, copper, and zinc alloys with high aluminum content. In this process, the metal is melted first in a separate crucible. A certain amount of molten metal is then transferred to an unheated injection chamber or nozzle. The metal is injected into the mold by hydraulic or mechanical pressure. The disadvantage of this process is the long cycle time, since the molten metal needs to be transferred into a cold chamber. Cold chamber die casting machines are also divided into vertical and horizontal. Vertical die casting machines are usually small machines, while horizontal die casting machines have various models.