HPDC

High-pressure die casting (HPDC) is a metal casting process in which molten metal is forced under high pressure into a steel mold, or die, to produce large volumes of parts with good dimensional accuracy and surface finish.

Two principal machine configurations exist: hot-chamber die casting, where the alloy is melted inside the machine and injected directly into the die (commonly used with zinc and magnesium alloys); and cold-chamber die casting, where molten metal is poured into a separate shot chamber and then injected under high pressure (typical for aluminum and copper alloys).

Die casting uses complex, hardened steel dies to form the part. After injection, the metal rapidly cools and solidifies; the part is ejected, trimmed of flash, and further finishing may be applied. The process achieves short cycle times, enabling high production rates.

Common HPDC alloys include zinc, aluminum, and magnesium. Zinc alloys are easy to cast and offer good detail at low costs; aluminum provides higher strength-to-weight ratios; magnesium offers light weight but greater reactivity and processing challenges.

Applications span automotive components (engine and transmission housings, intake manifolds), automotive and consumer electronics housings, power tools, and small mechanical parts requiring tight tolerances and net shapes.

Advantages of HPDC include high production rates, good dimensional accuracy, thin walls, and the ability to produce complex geometries with good surface finish. Disadvantages include high tooling and equipment costs, substantial energy use, and susceptibility to porosity or gas-related defects if process control is not maintained.

Quality and post-processing considerations include controlling porosity, shrinkage, and cold shuts; achieving proper mold temperature, venting, and material cleanliness; and performing trimming, deburring, and optional heat treatment or surface finishing.

HPDC has been widely adopted in mass production since the mid-20th century and remains a core process for producing small to medium-sized parts with tight tolerances.