0Metal Casting:
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Sand casting uses ordinary sand as the primary mould material.
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The sand grains are mixed with small amounts of other materials, such as clay and water, to improve mouldability and cohesive strength, and are then packed around a pattern that has the shape of the desired casting.
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The pattern must be removed before pouring, the mold is usually made in two or more pieces.
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An opening called a sprue hole is cut from the top ofthe mold through the sand and connected to a system of channels called runners.
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The molten metal is poured into the sprue hole, flows through the runners, and enters the mold cavity through an opening called a gate.
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Gravity flow is the most common means of introducing the metal into the mold.
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After solidification, the mold is broken and the finished casting is removed.
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The casting is then “fettled” by cutting off the ingate and the feeder head.
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Because the mold is destroyed, a new mold must be made for each casting.
