Die casting is a metal casting process that is characterized by forcing molten metal under high pressure into a mold cavity. The mold cavity is created using two hardened tool steel dies which have been machined into shape and work similarly to an injection mold during the process.
Depending on the melting point of metal being cast, there are two main types of die casting machines-hot chamber die casting machines (used for alloys with low melting point, such as zinc alloy, magnesium alloy) and cold chamber die casting machines (used for alloys with high melting point, such as aluminum alloy).
Most die castings are made from non-ferrous metals, specifically zinc, copper, aluminium, magnesium, lead, pewter, and tin-based alloys.
The die casting process cycle is relatively simple, involving only four main steps: clean, lubricate and clamp the two die halves, inject molten metal into the die, cool and solidify, open the die halves and push the castings out), which keeps the incremental cost per item low.
Die castings are characterized by a very good surface finish and dimensional consistency.
Two variants are pore-free die casting, which is used to eliminate gas porosity defects; and direct injection die casting, which is used with zinc castings to reduce scrap and increase yield.