The injection molding process for metals is very similar to that for plastics. A distinction is made between cold chamber and hot chamber die casting. Both techniques use a mold in which the material is pressed under high pressure. After the material has cooled, the product is ejected from the mold, after which the mold closes again and the cycle starts again.
The difference between the cold chamber and the hot chamber results from the way in which the material enters the injection chamber. In cold chamber die casting, a measured amount of molten material is poured into the injection chamber from a ladle. The machine itself has no provisions to melt the material. A plunger pushes all material from the injection chamber into the mold. The pressure is between 15 and 70 MPa.
Because the heated material only comes into contact with the parts of the machine and the mold for a short time, this method is very suitable for processing aluminum and aluminum alloys. If the material had been in contact with the injection chamber longer, such as with hot chamber die casting, it would wear much faster. The lifespan of a mold varies between 50,000 and 250,000 shots.