What is the Die Casting Process?

Die casting allows for the design and manufacture of complex metal components. Offering exceptional accuracy and high-volume production run capabilities, die casting provides the tight tolerance needed for a variety of high-performance metal components.

Basic Die Casting Process

The basic die casting process for metal fabrication is as follows:

  • Clamping/Die Preparation. Die is lubricated and prepped for clamping. Die is then closed, clamped, and ready for injection.
  • Die Filling/Injection. Molten metal (aluminum, magnesium, and zinc are commonly used) is injected and sealed into a mold cavity.
    • The mold is compressed until the metal solidifies and cooled. Cooling time is dependent upon the complexity and wall thickness of the die
  • Ejection. Ejector pins release the casting from the die cavity. 
  • Shakeout. Excess material is trimmed from the casting. Shakeout separates scrap metal from the cavity

How Long Does a Die Casting Cycle Take?

The die casting cycle time depends on the weight of the components. While typically a very quick process, die casting can take from a few seconds for small components to a few minutes for large, heavier components. The quick cycle times allows you to complete high production runs as efficiently as possible.

Die Casting Methods

While the overall process of die casting remains the same, there are 2 methods that are used when injecting the molten metal into the die cavity. Hot chamber and cold chamber methods are used for different metals, largely dependent upon their melting points.

Hot Chamber Die Casting Method

Hot chamber die casting is a method where the metal is an internal process. The metal is heated inside the casting chamber.

  • Low melting temperature alloys such as magnesium, lead, and zinc are ideal for hot chamber die casting. This method is ideal for alloys that will not erode metal cylinders or plungers.

Advantages of hot chamber die casting include:

  • Longer die life. This is due to the lower melting points of alloys used with this method.
  • Reduced porosity
  • Fast die casting cycle times when compared to cold chamber casting
  • Efficient die designs

Cold Chamber Die Casting Method

Cold chamber die casting is where the metal is melted/heated in a separate furnace and then transferred to the casting chamber. The molten metal is ladled into the casting machine and then then shot into the die cavity via a hydraulic plunger.

  • Cold chamber die casting method is perfect for metals with a high temperature melting point like aluminum, brass, or copper.

Advantages of cold chamber die casting include:

  • Produces denser metal castings
  • Low maintenance cost
  • Higher level of quality control due to the injection process

Differences between Hot Chamber and Cold Chamber Die Casting Methods

  • Hot Chamber Die Casting. Used for alloys with low melting temperatures. The melting pot is an internal part of the machine.  
  • Cold Chamber Die Casting. Used for alloys with high melting temperatures. Molten metal is melted via melting pot outside of the casting chamber. It is then ladled into the chamber and then injected into the die.

Selecting the Right Die Casting Method for Your Needs

Knowing which die casting method will be best suited for your project requirements can be confusing and frustrating. Work with die casting sourcing experts to ensure your die cast components are manufactured with the precision and accuracy needed for high-performance metal products.

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