Metal Casting

Casting

pouring liquid metal into a mold to harden

Pattern

a full-size copy of the part, used to make the mold

Cope and drag

the top and bottom halves of a sand mold

Core

an insert that forms a hollow inside the casting

Sprue

the channel the metal is poured down

Gate

the opening where metal enters the part

Riser

a reservoir that feeds metal as the part shrinks

Shrinkage allowance

how much larger the pattern is than the part

Expendable mold

a mold used once and broken

Permanent mold

a metal mold used again

Die

the steel mold in die casting

Draft

a slight taper so the part leaves the mold

Ejector pin

a pin that pushes the part out of the die

Flash

thin fins of metal at the mold split

Porosity

small holes or bubbles inside a casting

Misrun

a casting that froze before the mold filled

Cold shut

a weak seam where two flows of metal met but did not fuse

Hot tear

a crack that opens while the casting cools

Parting line

where the two mold halves meet

Undercut

a feature that would lock the part in a two-part mold