What is Pressure Die Casting? – Definition, Types, Uses, and more


Pressure die casting is a metal casting process that is commonly used to produce complex products with close dimensional tolerances. In pressure die casting, molten metal is injected under high pressure into a steel mold cavity using a hydraulic piston or plunger. The molten metal is forced into the mold cavity and solidifies to take on the exact shape of the mold. This allows for intricate and precise geometries to be replicated. The ability to fill the mold cavity very quickly allows for rapid solidification and thinner walls compared to other casting methods. Pressure die casting is capable of producing parts with details as small as 2-3 millimeters thick. It is well suited for casting metals with lower melting points like zinc, aluminum, magnesium, and copper alloys. Some common applications of pressure die casting include automotive components, appliances, valves, hardware, and various structural parts that require precision dimensions and surfaces.

Materials Are Used in the Process of High-Pressure Die-casting

The main materials are aluminum and magnesium alloys for the cast parts, with tool/die steel used for the dies and lubricants applied to enhance the casting process.

Aluminum is the most commonly cast material due to its lightweight, corrosion resistance, and ability to take on complex shapes. Common aluminum alloys include Aluminum 380, 390, 356, 443, etc.

Magnesium alloys are also die-cast but to a lesser extent than aluminum due to higher cost. They provide an improved strength-to-weight ratio over aluminum.

Zinc alloys are die-cast for parts that require good detail, strength, and corrosion resistance at a lower cost than aluminum or magnesium.

Die steel (usually heat-treated H-13 tool steel) is used to fabricate the dies due to its high hardness, wear resistance, and ability to withstand the heat and pressures of molten metal injection.

Some thermoplastics like nylon and PBT can also be die-cast but require lower temperatures and pressures than metal casting.

Lubricants like diesel oil or water-soluble oils are applied to the die cavities to aid ejection and reduce die wear during high-speed casting cycles.

Types of Pressure Die Casting

The key types are distinguished by the pressures used, hot/cold die temperatures, and mold materials like sand versus metal dies.

TypePressure RangeDie TemperatureMold MaterialKey Features
High-Pressure Die Casting (HPDC)Above 600 tonsColdMetal diesVery fast cycles, fine details
Low-Pressure Die Casting20-200 tonsColdMetal diesThicker sections, looser tolerances
Cold Chamber Die CastingHighWater-cooled diesMetal diesMinimal shrinkage, accurate parts
Hot Chamber Die CastingHighHeated diesMetal diesContinuous process, low tolerances
Pressure Sand CastingGas pressureN/ASand moldsMade using sand instead of metal dies
Vacuum Die CastingPartial vacuumColdMetal diesEliminates porosity in aluminum

Key Factors Affecting Mold Design in Pressure Die Casting

Applications of Pressure Die Casting

Essentially, any part that needs complex shapes in high volumes is a candidate for pressure die casting. It’s all about speed, precision, and net shape-forming capabilities.