What is Aluminum Die Casting?

When you’re in the process of designing an aluminum part, it is essential to consider which manufacturing process you’ll use to produce it. There are various methods for forming aluminum, and aluminum die casting is one of the most common options for designers to consider.

Aluminum die casting is the method of choice for many automotive, industrial, and telecommunications products. It’s also often used to produce electrical, hydraulic, and lighting components.

If you would like to know more about the aluminum die casting process and would like some help deciding if it is the right choice for your application, you’re in the right place.

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.

No. 1 – The Advantages of Aluminum Die Casting

Die casting aluminum offers several advantages over other metal-forming processes that might make it the appropriate choice to create your aluminum parts.

One of the most noteworthy is the ability to produce very complex shapes that neither extrusion nor machining can effectively create. A perfect example of this is the production of complex automotive parts, like transmissions and engine blocks. Other processes cannot consistently achieve the complexity and tight tolerances required for these products.

Additional advantages include the ability to have textured or smooth surfaces and the capacity to accommodate both large and small parts.

No. 2 – The Top Considerations During Part Design

A few considerations have to be taken into account when designing the part to be cast.

Firstly, the mold must be designed to separate and allow the solidified aluminum part to come out. The line that marks where the two halves of the mold come apart is referred to as a parting line, and you have to consider it in the early stages of die design.

Another important consideration is the location of injection points. The die can be designed with several injection points in cases when the molten metal would otherwise solidify before reaching every crevice in the die. This can also help if cavities are included in the design; you can surround them with aluminum and still have the part come off when the mold is separated.

You must also consider the thickness of the part’s walls. There are usually no guidelines for a minimum wall thickness, thanks to recent technology developments, but having walls with consistent thickness is often preferred.

No. 3 – How it Compares to Green Sand and Permanent Mold Casting

Green sand and permanent mold are two common die casting processing to provide aluminum die casting processing service. Green sand processes use wet sand to create the mold for the cast, making it less expensive than the other two processes. Above, you can see an operator pouring molten metal into a sand cast mold.

Unlike die casting, which uses injection, permanent mold castings require the molten aluminum to be gravity poured into the mold. Permanent mold castings can also potentially produce stronger casts.

Nevertheless, die casting offers better tolerances and better-finished surfaces than the other two methods, often eliminating the need for subsequent surface treatment.