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Explain sand casting
A solid re-usbale pattern (often wooden) is made of the component
Sand with a small amout of resin binder is packed arounf the pattern in a box called a drag
The drag is inverted and the patern is lifted out, leaving a cavity. Ingates and runners may be carved or moulded into the sand
Interior detail may be produced by inserting a core into the cavity
Upper part of the mould called a cope formed from sand, incioperating a poring basin, a sprue, ventsm risers/feeder heads
Mould bolted together, metal poured in
Once the casting has soldified the mould is removed and the sand mould and any cores broken up and brushed out
The casting is fettled: curtting off
The parting line of the mould may also leave a ridge which must be gorund of
What is investment casting?
Expendable wax pattern which is coated in a ceramic shell to make an expendable mould
