High-pressure die casting

In this process, the liquid metal is injected at high speed and high pressure into a metal mould. A schematic view of high pressure die casting is given in Figure.This equipment consists of two vertical platens on which bolsters are located which hold the die halves. One platen is fixed and the other can move so that the die can be opened and closed. A measured amount of metal is poured into the shot sleeve and then introduced into the mould cavity using a hydraulically-driven piston. Once the metal has solidified, the die is opened and the casting removed.

In this process, special precautions must be taken to avoid too many gas inclusions which cause blistering during subsequent heat-treatment or welding of the casting product.

Both the machine and its dies are very expensive, and for this reason pressure die casting is economical only for high-volume production.

 

Advantages of die casting:

  • High precision and capability.
  • Little or no machining required.
  • Smooth surfaces; surface treatment made redundant or more attractive and economical.
  • Thin-walled, less weight, without the loss of strength.
  • Holes, ribs, grooves, letters and figures are already cast.
  • Excellent electromagnetic shielding and electrical and thermal conductivity.
  • Manufacture of complex parts, allowing the integration of several parts and functions in one die cast part.
  • Inserts (axes, screws,…) of other materials (steel, bronze, copper,…) can be cast into the part.
  • Scientific process control and guaranteed high quality.
  • Less controls and assembly costs.
  • Rapid and flexible delivery: customers require less or no stock