Mechatronic Systems Engineering 3301A/B Lecture Notes - Lecture 25: Selective Laser Melting, Dielectric, Stereolithography
12 Aug 2020
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Document Summary
A liquid is poured or forced into a mold where it solidifies by cooling. Casting is distinguished from molding by the low viscosity of the liquid. The liquid fills the mold by flow under its own weight or under a modest pressure. Cast shapes must be designed for easy flow of liquid to all parts of the mold, and for progressive solidification that does not trap pockets of liquid in a solid shell, giving shrinkage cavities. The tolerance and surface finish of a casting vary from poor for sand casting to excellent for precision die castings. Sand casting liquid metal is poured into a split sand mold. Die casting liquid is forced under pressure into a metal mold. A wax pattern is embedded in a refractory, melted out, and the cavity filled with metal. A die is filled from below, giving control of the atmosphere and of the flow of metal into the die.
