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•Advantages,

-good uniform metal properties

-no sprues/gates to remove

-the outside of the casting is at the required dimensions

-lower material usage

-no parting lines

-low scrap rates

•Disadvantages,

-extra equipment needed to spin mold

-the inner metal of the part contains impurities

45.3.4 Casting/Forming Combinations

• These processes basically casting molten metal, but the use mechanical force to reshape.

45.3.4.1 - Squeeze Casting

•The basic process is,

1.Molten metal is poured into an open face die.

2.A punch is advanced into the die, and to the metal.

3.Pressure is applied to the punch and die while the part solidifies. This pressure is lower than normally required for forging.

4.The punch is retracted, and the part is knocked out with an ejector pin.

•This method overcomes problems with feeding the die, and produces near net, highly detailed parts.

45.3.4.2 - Semisolid Metal Forming

•The basic process is,

1.A metal is heated until it has thixotropic properties (when agitated viscosity decreases).

2.The metal is poured into a die in a semi-solid state, and the mold is filled.

3.The metal hardens.

•This can produce better metal qualities in net shape parts requiring no finishing operations.