Gravity Die Casting - RENYI CASTINGS
With sand casting the mold is broken up after each casting operation, but with the process known as gravity die casting, the mold also called a 'die' is manufactured from metal, and can be used a large number of times. This means that the die is much more expensive to make, than an expendable 'one use only' mold. An intermediate technique makes use of semi-permanent molds, which are made of gypsum plaster or fireclay, which can be used repeatedly for a limited number of castings. With gravity die casting, the most widely used materials for die-making are cast iron, steel, and heat resisting alloys of iron. For some specific purposes other materials are used to manufacture the dies, and these can include, aluminum. Copper or graphite. A metal die can produce smooth castings with a clean surface, and a very high dimensional accuracy. These castings require very little or no final machining or other finishing treatment. The service life of metal dies can vary in terms of
