The minimum cross-sectional area and minimum draft angle corresponding to various materials are listed in the following table, and the thickest cross-section should be less than 13 mm [4]
metal
Minimum cross-sectional area
Minimum draft angle
Aluminum alloy
0.89 mm (0.035 in)
1:100 (0.6°)
Brass and bronze
1.27 mm (0.050 in)
1:80 (0.7°)
magnesium alloy
1.27 mm (0.050 in)
1:100 (0.6°)
Zinc alloy
0.63 mm (0.025 in)
1:200 (0.3°)
Metals used for die casting mainly include zinc, copper, aluminum, magnesium, lead, tin, and lead-tin alloys. Although die-cast iron is rare, it is also feasible. Relatively special die-casting metals include ZAMAK, aluminum-zinc alloys, and Alcoa Standards: AA380, AA384, AA386, AA390, and AZ91D magnesium. The characteristics of various metals during die casting are as follows:
Zinc: the most easily die-cast metal, it is economical when manufacturing small parts, easy to coat, high compressive strength and plasticity, and long casting life.
Aluminum: light weight, complex manufacturing and thin-wall castings, high dimensional stability, strong corrosion resistance, good mechanical properties, high thermal conductivity and electrical conductivity, and high strength at high temperatures.
Magnesium: easy to machine, high strength-to-weight ratio, the lightest of commonly used die-cast metals.
Copper: High hardness and strong corrosion resistance. Among the commonly used die-cast metals, it has the best mechanical properties, wear resistance, and strength close to steel.
Lead and tin: high density and extremely high dimensional accuracy, can be used as special anti-corrosion parts. Due to public health considerations, this alloy cannot be used as a food processing or storage facility. An alloy of lead, tin, and antimony (sometimes containing a little copper) can be used to make manual typefaces and bronzing in letterpress printing.
The upper mass limits for die casting using aluminum, copper, magnesium, and zinc are 70 lb (32 kg), 10 lb (4.5 kg), 44 lb (20 kg), and 75 lb (34 kg), respectively.