Hot-Chamber Machines: The main components of the hot-chamber machine are a steel pot with molten metal in it and a pumping system consisting of a pressure cylinder, a plunger, a gooseneck passage and a nozzle. When the plunger is in the up position molten metal flows by gravity through the intake ports into the hot-chamber. When the power cylinder pushes down the plunger it shuts off the intake ports and forces the metal through the gooseneck passage and nozzle into the die cavity. High pressure is maintained to allow the casting to completely solidify, then the two halves of the die are pushed apart and the ejector pin knocks out the casting. Finally the die cavity is cleaned and lubricates and the cycle begins again. The advantages to hot-chamber casting include: high production rates, improved conductivity, superior surface finish, close tolerances and the ability to produce intricate shapes with thin walls. It does have limitations, however. Only low melting point alloys like zinc, tin and lead can be used because the parts of the pumping system are in direct contact with the molten metal for long periods of time. The process is also usually only suitable for making small castings that weigh less than ten pounds.

Cold-Chamber Machines: For cold-chamber machines the molten metal reservoir is separate from the casting machine and just enough metal for one shot is ladled on every stroke. The metal is poured into the pouring hole of the shot chamber while the two halves of the die are locked together. Then the plunger moves forward, closing the pouring hole and forcing the molten metal into the die cavity. After solidification the die is opened and the casting is ejected from the die. As the chamber and plunger are in contact with the molten metal for shorter times, metals with higher melting points, such as aluminum, magnesium and brass, can be used in the process. It is also possible to produce large parts weighing up to fifty pounds by this process, but it does have a longer cycle than hot-chamber die casting.

Slush Casting: Slush casting is a process for making hollow articles by inverting the mold after partial freezing on the surface in order to drain out the still liquid metal at the center. Solidification begins at the walls because they are relatively cool and works inward, so the thickness of the shell is controlled by the amount of time allowed before the mold is drained. This is a relatively inexpensive process, however only low melting point alloys with narrow freezing ranges can be used and it is a slow method, requiring close temperature control of the liquid metal.

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