1.0 Introduction
Casting as a method of fabrication is defined ceramics into a fire proof container or mould to solidify with the purpose of forming a desired shape. If they are permitted to retain this shape or are reshaped by machining operations only, the objects are called casting. If the object formed are subjected to subsequent deformation such as rolling forging, the original shape are called ingots.
Casting is one of the oldest fabrication of machine parts, moulds, fitting, equipment etc
There are various methods of casting moulds machine parts and fitting. These include sand mould casting which makes use of sand mould, permanent or metal mould casting which uses metallic mould and ceramics mould casting which uses ceramic mould. Each moulding method has certain inherent advantages and limitation. The choice of a particular moulding method depends on factors such as size and shape of castings, dimensional accuracy, surface finish metallurgical properties, production, quantities and cost.
The mould used for casting may be made of metals sand or ceramics. Metallic mould are usually permanent mould used where mass production of identical objects are desired such as casting of steel ingots, in cast iron mould, and casting of automobile piston. Sand mould and ceramics mould are usually temporary moulds.
Sand mould are made of sand moistened with a binder such as molasses or clay (French sand) and used in this moist condition in which case it is called a green sand mould or it may be baked to dryness and therefore referred to as dry sand mould.
Sand mould casting is the most variable all the forming processes, and provided the greatest freedom of design in terms of shape, size and product quality. Moreover, sand mould casting is relatively cheap, easily available and can easily be undertaken by small scale production of machine points equipment fitting.
The choice of casting materials depended on such factors as cost, durability, corrosion resistance and metallurgical properties. The choice of aluminum as the fabrication materials of the candle is due to its relative availability low melting point (6660), high fluidity on melting and corrosion resistance.
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