Die casting is a highly efficient liquid metal forming method with less and no cutting. It uses a die-casting machine to press molten liquid or semi-liquid metal into a metal cavity under high pressure to quickly fill the mold, and then shapes and solidifies under pressure to obtain castings.

Characteristics of die casting

Advantage

1) High productivity, easy to implement mechanization and automation, and can produce thin-walled castings with complex shapes. The minimum wall thickness of die-cast zinc alloy is only 0.3mm, the minimum wall thickness of die-cast aluminum alloy is about 0.5mm, and the minimum cast hole diameter is 0.7mm.

2) Castings have high dimensional accuracy and small surface roughness. The dimensional tolerance level of die castings can reach CT3~CT6, and the surface roughness is generally Ra0.8~3.2μm.

3) Parts can be embedded in die-casting parts, which not only saves valuable materials and machining hours, but also replaces the assembly process of components, which can eliminate the assembly process and simplify the manufacturing process.

Shortcoming

1) During die-casting, the filling speed of liquid metal is high, and the gas in the cavity is difficult to completely eliminate. Castings are prone to defects such as pores, cracks, and oxidized debris. Die-castings usually cannot be heat treated.

2) The die-casting mold has a complex structure, long manufacturing cycle, and high cost, and is not suitable for small batch casting production.

3) The die-casting machine has high cost and large investment. It is limited by the clamping force and mold size of the die-casting machine, and is not suitable for the production of large-scale die-casting parts.

Suitable materials for die casting

Die casting is only suitable for metals with higher fluidity. The metals used for die-casting mainly include zinc, copper, aluminum, magnesium, lead, tin and lead-tin alloys. Special die-casting metals include ZAMAK, aluminum-zinc alloy and American Aluminum Association standards: AA380, AA384, AA386, AA390 and AZ91D magnesium. The characteristics of die casting of various metals are as follows:

Zinc: The easiest metal to die cast, economical to manufacture small parts, easy to coat, high compressive strength, plasticity, long casting life.

Aluminum: Light weight, high dimensional stability when manufacturing complex and thin-walled castings, strong corrosion resistance, good mechanical properties, high thermal and electrical conductivity, and high strength at high temperatures.

Magnesium: Easy to machine, has a high strength-to-weight ratio, and is the lightest of the commonly used die-cast metals.

Copper: high hardness, strong corrosion resistance, the best mechanical properties among commonly used die-cast metals, wear resistance, and strength close to steel.

Lead and Tin: High density, extremely high dimensional accuracy, used as special anti-corrosion components.