What is Aluminum Die Casting? Aluminum die casting is a metal-forming process that allows for the creation of complex aluminum parts. Ingots of aluminum alloy are heated to very high temperatures until they are entirely molten. The liquid aluminum is injected under high pressure into the cavity of a steel die, also known as a mold — you can see an example of a mold for automotive parts above. The die is made up of two halves, and after the molten aluminum has solidified, they are separated to reveal the cast aluminum part. The resulting aluminum product is precisely formed with a smooth surface and often requires minimal or no machining processes. Given that steel dies are used, the process can be repeated many times using the same mold before it deteriorates, making aluminum die casting ideal for the high-volume production of aluminum parts.