2008-Jun-19 - About Metal Casting

Die-casting: Die casting can be defined as a process of ‘forcing molten metal’ into cavities of mold under high pressure. These castings comprise of nonferrous metals, especially-alloys of aluminum, copper, and zinc. It is even possible to make die castings of metal. The method of die casting is used where finer parts are needed.

‘Permanent Mold Casting’: This casting is made up of non-ferrous metals. It requires some time to set up (some weeks), after which the production rate of about 5 to 50 pieces/hour-mold is achieved. The coating of ‘acetylene soot’ is applied to steel cavities. This helps in removing the work piece easily and promoting longer life (of tools). Permanent molds possess a limited life span. For worn molds, replacement or refinishing is required.

Expendable mold casting: ‘Expendable Mold casting’ can be referred to as a standard classification inclusive of the following:

Sand casting: It is amongst the simplest and most popular casting types used since ages. It involves very small size operations. The bonding of sand takes place by use of clays (as in ‘green sand’) or ‘polymerized oils’, or ‘chemical binders’. Recycling is easily possible.

Plaster casting (for metals): There is no difference between plaster casting and sand casting, except the fact that plaster is used in place of sand. Similarly, there are also plastic and concrete castings.