Die Casting: Process, Materials, Advantages, Disadvantages

Get to know die casting, a method of producing high volumes of detailed, geometrically complex metal parts. Learn what it is, the types of die casting process, what it’s used for, and its advantages and disadvantages.

What is Die Casting?

Die casting is a high-precision form of manufacturing metal parts. The processes used to die cast are similar to injection moulding, but they involve metal materials instead of plastic. Like injection moulding, die casting produces industrial grade parts from real production grade materials.

Aluminium Die Casting

Example of Die Cast Parts Made at HLH Rapid

The die casting process is very versatile and is capable of producing parts with complex geometries and tight tolerances. Manufacturers like using die casting because it produces high volume, functional end use parts with complex shapes, using industry grade materials like magnesium, zinc alloy, and aluminum. It is also a highly repeatable process that allows 100,000+ identical parts to be made with ease.

How It Works

High pressure die casting (HPDC) is a process that consists of four steps: mould preparation, filling, injection, and shake out.

Step 1: Mould Preparation: First, the mould is prepared by machining a negative image of the desired part into a block of steel. The mould can be single cavity, multi-cavity, combination and unit die.
Step 2: Material Preparation: Next, metal material typically an alloy, such as aluminium, magnesium, or zinc, is melted in a furnace then poured into a ladle.
Step 3: Injection: Once the metal is in a liquid state, it is injected into the mould tool cavity under high pressure, taking the shape of the mould.
Step 4: Casting: Lastly, the solidified part is removed from the mould and finished in post processing.

Type of Die Casting Processes

There are two main types of die casting process: hot-chamber and cold-chamber die casting.

Hot Chamber

This method of die casting, also called gooseneck casting, is the most popular one in use today. It works by immersing a chamber of the injection mechanism in molten metal, thereby heating it up. Then, a metal feed system in the shape of a gooseneck directs the molten metal from the injection mechanism into the mould tool cavity. Hot chamber die casting works best for metals with lower melting points such as magnesium, tin, lead alloys.

Cold Chamber

In this die casting process, molten metal is ladled directly into the injection system. This means that the injection system doesn’t need to be immersed, hence the name “cold chamber.” Manufacturers use the cold chamber process to minimize machine corrosion. Cold chamber die casting works best for metals with high melting points such as aluminum, brass, and copper.

Materials Used in Die Casting

Whether the material is suitable for the die casting process depends on several factors. Firstly, it needs to be able to withstand the high temperatures and pressures of the die casting process. Other considerations include surface finish, material structural properties and other demands of your end-use application. Popular materials that are compatible with the process include non-ferrous, malleable metals like aluminum, magnesium, and zinc.

Aluminium Alloys	Good corrosion resistance Good mechanical properties High thermal and electrical conductivity More surface finishing options
Magnesium	Excellent stiffness Excellent strength-to-weight ratio Perfect for connectors and electrical housings
Zinc Alloy	High ductility Good physical and mechanical properties Easiest to cast

What is Die Casting Used For?

Die cast parts are most commonly made for use in automotive and decorative hardware applications. The process can be used to create a wide variety of parts and products, from engine components to toys. Die casting is also used in the production of many common household items, such as door-knobs and faucets.

Advantages Of Die Casting

Lower Cost Per Part: With die casting, the more parts produced, the lower the cost per part.
Accurate and Repeatable: The die cast moulds hold up to multiple uses and consistently deliver the same accuracy.
Good For Larger and More Complex Parts: The process can produce complex-shaped parts within closer tolerances than many other mass production processes.

Disadvantages Of Die Casting

Porosity: If the molten metal cools down too quickly in the mould, it is likely to develop a porous structure.
High Initial Investment: The cost of starting a die casting project is high.
Not Suitable For One-Offs: The fact that we have to make a custom die mould for each new casting project makes this method unsuitable for one-off productions.

Start you next die casting project

Die casting is a complex process that when executed correctly, can deliver cost-effective, efficient and durable results. Therefore, it is strongly advisable to consult with a tooling and plastic injection moulding professional when undertaking such projects.

To get started on your next die casting project, simply submit your CAD designs and project details via our site contact form, and our team will get back to you with a quote within 24 hours.