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A press typically works with room temperature metal, or metal hot enough to be slightly soft. The blank is placed inside, and the press comes down and crushes i
by chiph 6y ago
A press typically works with room temperature metal, or metal hot enough to be slightly soft. The blank is placed inside, and the press comes down and crushes it into the shape dictated by the mold. Excess metal is sometimes cut off by sharp edges on the mold.
A die casting process starts with molten metal, and the metal is injected under pressure to fill the die cavity. The mold is separated and the new part is removed.
https://www.youtube.com/watch?v=iSyBsdJkQu8 https://www.youtube.com/watch?v=iSyBsdJkQu8
After die casting and the part cools, a press may be used to trim any excess off.
- baybal2 6y agoInjection casting is quite a bit newer than gravity casting, which dominated the industry until 197x-198x. Gravity casting had problem with voids, and fine features, but otherwise much more economical. Injection, or semisolid casting is much more expensive, both because of more expensive machinery, and mold expense.
- chiph 6y agoGravity casting using sand molds were, like you said, just how you did it until that time. Dad had an early 90's Saturn SL, and it's engine used the lost-foam casting process. You could see the surface texture in the metal from where the polystyrene had expanded when it was made. Sand molds weren't able to show a feature that fine. https://en.wikipedia.org/wiki/Saturn_I4_engine https://en.wikipedia.org/wiki/Saturn_I4_engine https://en.wikipedia.org/wiki/Lost-foam_casting https://en.wikipedia.org/wiki/Lost-foam_casting
- baybal2 6y agoEngine blocks are still sand cast, and there is not much need to use anything else for their production if you can nail the fluid dynamics in the mold. Only very small scooter engines I know are mold/semisold cast, everything else I know is gravity cast.