Die casting is the process in which under high pressure molten metal is forced into moulds. Many metals used in the casting of dies are nonferrous unlike other casting processes, such as powder metallurgy. Examples include aluminum, pewter magnesium, zinc, Zamak in Zamak Die Casting and lead. Just about 150 years ago this process was invented so that the printers could make pieces of movable type more easily and quickly than they could do by using older methods.
Types
The two basic categories are the hot-chamber casting and cold-chamber casting. There are also secondary types, such as semi-solid, vacuum and squeeze. Hot-chamber is the most common because in the same apparatus it combines the liquefying and injecting procedures.
The pieces created through hot-chamber casting are more susceptible to corrosion because of variety of reasons. This means that for metals with a low melting point, such as magnesium, lead, and zinc hot-chamber casting is best suited. However, this method works best with single metals and not alloys because of the relatively low temperature that is suited for hot-chamber casting.
The combustion chamber from the injection apparatus is removed in cold chamber casting and uses it what is basically a straw to form the conduit for the molten metal. Its major advantage is that to their melting points it can heat various metals, even if those that are higher than that of others, because with ultra-high melting points the melting chamber can be constructed of material, such as tungsten.
Not only to pump the molten material it takes extra time, but because the material also must be heated in a separate location, it is also more expensive. It is the only method available for metals with higher melting points, such as molybdenum, copper and manganese in order to avoid the corrosion problems later.
