There are several metals commonly used for die casting, the most common of which are zinc, aluminum, magnesium, copper, lead and tin. Each metal has its own advantages and disadvantages, and each meets the corresponding industry requirements.

Aluminum

· Low density/lightweight

· High corrosion resistance

· High casting temperature

· Very stable in nature

· High electrical conductivity, which makes it widely used in the electrical industry

· High thermal conductivity

· Recyclable

· Relatively easy to cast

· Requires a cold chamber die casting machine to die cast, unlike the other metals on this list, which can be cast in a hot chamber die casting machine.

Zinc

· High density

· Good ductility

· Good impact strength

· Very good surface smoothness

· Can die cast very thin or delicate parts

· Low melting point, casting molds will last much longer than molds for some other metals

· Susceptible to corrosion, usually requires additional spray coating or plating before use

Magnesium

· Very low density

· Very high strength to weight ratio

· Easy to cut

· Shows excellent machinability even after casting and machining, and can be machined in hot or cold chamber machines

Susceptible to creep or cold flow, generally not suitable for use in very high temperature or high stress environments, but as magnesium becomes more popular in global industry, various magnesium alloys are now available to overcome this weakness

Copper

·High toughness and strength

·Resistant to corrosion and wear

·High stability

·High electrical conductivity

·Very high melting point, so molds and die casting machines used to cast copper tend to have shorter lifespans than those used to process other metals

Lead and Tin

·Both have high density

·Both have high dimensional accuracy of die castings

·For public health reasons, lead and tin are not allowed to be used in any product that comes in contact with food. However, they are often used in combination with some of the metals listed above to improve corrosion resistance.

Die Casting Process

Each die-cast metal part is formed in a mold, and each mold is specially designed. The die-casting pressure is several MPa to tens of MPa, the initial filling speed is 0.5-70m/s, and the filling time is very short, only 0.01-0.03s. Therefore, high pressure and high speed are important characteristics of the die-casting process, which also make the die-casting process, the structure and performance of die-casting parts and the design of die-casting molds have their own characteristics.

Common closed die castings use a two-piece mold, which is cut into two separate metal blocks. When the mold blocks are placed together and the cavities are aligned, a complete mold can be formed. During the use of the mold, it is necessary to spray it with lubricant to help control its temperature and help the part demold after the casting is completed.

When the die casting starts, the mold is closed, the metal solution is poured into the injection sleeve and injected into the mold under high pressure through the plunger. The pressure is maintained in the mold until the casting solidifies, then the mold is opened and the ejector pushes out the solidified die casting.