Die Casting Process Guide — Hot Chamber vs Cold Chamber

Complete guide to die casting: hot chamber vs cold chamber, tooling design, alloys, applications, and quality control.

What is Die Casting?

Die casting forces molten metal under high pressure into a steel mold (die). It produces high-volume, dimensionally accurate metal parts with excellent surface finish.

Hot Chamber Die Casting

Injection mechanism submerged in molten metal. Best for low-melting-point alloys. Cycle times are faster.

• Alloys: Zinc, ZA alloys, magnesium, tin
• Pressure: 1,000-3,000 psi
• Cycle: 1-10 seconds
• Pros: Fast cycle, low porosity, good finish
• Cons: Limited to low-temp alloys

Cold Chamber Die Casting

Molten metal ladled into injection chamber then pushed into die. For high-melting-point alloys.

• Alloys: Aluminum, brass, copper, magnesium
• Pressure: 3,000-15,000 psi
• Cycle: 20-90 seconds
• Pros: Handles high-temp alloys, larger parts
• Cons: Slower cycle, more porosity

Key Alloys

• Zamak 3 (Zinc): Excellent stability, easy to plate. Tensile 283 MPa.
• Aluminum A380: Most common. Good fluidity and strength. Tensile 324 MPa.
• AZ91D (Magnesium): Lightest structural alloy (1.8 g/cm3).

Design Guidelines

• Draft Angles: 1-3 degrees min for Al, 0.5-1 degree for Zn
• Wall Thickness: 1.5-4 mm for Al, 0.8-3 mm for Zn
• Corner Radii: Minimum 0.5 mm