High-pressure die casting is a metal casting process that involves injecting molten metal — zinc, aluminum, magnesium, etc. — into a three-dimensional mould. The base metal is heated until it achieves a liquid, molten state. It’s then forced into the mould’s cavity, allowing it to take the shape of the mold once cooled.

High-pressure die casting is used to create everything from engine blocks to aerospace components and even heavy-duty fasteners. While there are different ways to perform it, most high-pressure die casting processes consist of the four following steps.

1) Mould Preparation

The first step of high-pressure die casting is mould preparation. During this initial step, the workers apply a lubricant to the interior walls of the mould. This is important because the lubricant regulates the mould’s temperature while also creating a film between the molten metal and the mold, thereby allowing for easier removal of the casting.

2) Injection

After preparing the die mould, the workers inject it with molten metal. The mould must be completed closed and sealed during this step. Otherwise, it won’t be able to “accept” the highly pressurized molten metal. The mould maintains this pressure until the molten metal has cooled and solidified.

3) Cavity Ejection

Then, the workers eject the newly made cavity from the mould. The mould itself typically features ejector pins that, when engaged, release the cavity. Of course, the cavity must be solid for it to eject. If the raw metal is still liquid, the workers must wait for it to cool before it can eject the cavity from the mould.

4）Shakeout

The final step of high-pressure die casting is shakeout. During this step, the workers separate any scrap metal from the newly created cavity. It’s not uncommon for high-pressure die casting to produce excess scrap metal. In other words, not all of the molten metal is used to create the casting. Some remains stuck inside the mould. As a result, the scrap metal must be removed before the mould can be reused.