Casting Processes

The first step in a manufacturing process is casting. In the casting process, material is liquefied by heating it in a furnace. This liquid is poured into a mould cavity and allowed to solidify. Once it gets solidified, it has to be trimmed and cleaned. Moulds can be prepared by wood or metal. Different metals used for this purpose are cast iron, cast steel, aluminium, bronze and brass. Commonly used mould patterns are loose pattern, gated pattern, match plate pattern, cope and drag pattern, sweep pattern and skeleton pattern. We can also construct moulds by plastics and green sand. In a green sand mould, a mixture of sand, clay, water and some organic additives are used. Organic additives commonly used are wood, floor, sea cod and dextrin. Melting is an important step in casting process. Controlled amount of specific gases has to be used during melting in order to avoid faulty castings. Choice of furnace and temperature differ with melting materials. During pouring process, gating design should be very effective to reduce temperature loss, low turbulence and minimum entrapping gases and slags.