IE 21 part 2

Process wherein a liquid material, most commonly molten metal, is introduced into a previously prepared cavity or mold, and permitted to solidify.

• Casting

• Sintering

• Manufacturing

This cavity must be of the desired shape and size, with due allowance for shrinkage of the solidifying metal.

• Shell molding

• Pattern allowance

• Mold cavity

Mold is only used once; usually destroyed in the removal.

• Multiple-use-mold casting

• Ceramic casting

• Expendable-mold casting

Most common, no limit on size and shape, low cost, almost any metal can be cast. Granular refractory material (such as silica, zircon, olivine, or chromite sand) is mixed with small amounts of other materials, such as clay and water, and is then packed around a pattern to form the mold.

• Investment casting

• Shell molding

• Sand casting

• Plaster mold casting

Compensates for the shrinkage of the metal as it solidifies and cools. Pattern must be slightly larger than the casting.

• Finish or machining

• Shrinkage or contraction

• Draft or taper

• Distortion or camber

Allowance for machining. Made slightly larger to compensate for the removal of material during machining

• Draft or taper

• Shrinkage or contraction

• Finish or machining

• Distortion or camber

Facilitates the withdrawal of the pattern.

• Draft or taper

• Shrinkage or contraction

• Finish or machining

• Distortion or camber

A supposed-to-be straight casting tends to curve outwards.

• Shrinkage or contraction

• Finish or machining

• Draft or taper

• Distortion or camber

Compensates for the rapping that is done to facilitate the removal of the pattern.

• Finish or machining

• Draft or taper

• Rapping or shaking

• Distortion or camber

Two piece frame contained in a mold

• Drag

• Cope

• Flask

• Sprue