Magnesium Die Casting Guide

Magnesium Die Casting inside 768x421 1

What is Magnesium Die Casting?

Magnesium die casting is a specialized manufacturing process utilized in the production of metal parts and components made from magnesium alloy. This process, often referred to as magnesium alloy die casting, involves injecting molten magnesium into a die or mold cavity under high pressure. The resulting product, also known as magnesium cast, is a complex shape or part that exhibits the unique properties of magnesium alloy.

The die casting manufacturing process for magnesium starts with the preparation of the magnesium alloy. The alloy is carefully melted in a furnace and subsequently injected into the die or mold cavity. Typically, the mold is constructed from durable materials such as steel and is meticulously designed to produce the desired shape of the final part.

Once the molten magnesium is introduced into the mold cavity, it undergoes rapid cooling and solidification under high pressure. This distinctive manufacturing method allows for the creation of intricate and complex shapes that would be challenging to achieve through alternative manufacturing processes.

Benefits of Magnesium Die Castings

Magnesium is a top choice for die-casting due to its unique properties, such as strength and durability combined with a lightweight structure, which is similar to plastic. Its unique features such as castability, ease of machining, and recyclability make it an excellent material option for die-casting strong but lightweight components. 

Magnesium alloys are 33% lighter than aluminum and 75% lighter than steel with excellent strength-to-weight ratio. With good thermal and electrical conductivity, magnesium is an excellent material choice for electronic components while also offering good shielding from electromagnetic or radio-frequency interference. Magnesium alloys have remarkable shock-absorbing properties that enable them to be used in applications where noise and vibration are of concerns.

Magnesium alloys, especially AS91D, have high fluidity, allowing for intricate features and thin walls to be casted. Although the cost of magnesium per pound is higher than aluminum or zinc, magnesium alloys provide more parts per pound and can offer significant cost savings in other ways. Magnesium has a lower heat capacity compared to aluminum, this means it will heat up and cool down faster, which decreases its production cycle time and increases productivity. Magnesium die casting machine tooling can last up to 4 times longer than its aluminum casting counterpart.  Furthermore, magnesium die cast parts are easier to machine, requiring less time and decreasing machining costs, making magnesium a good material choice for projects that requires a lot of secondary machining. Although magnesium die-casted parts usually remain uncoated due to their excellent surface finish, a variety of surface treatment options are available, including powder coat, liquid paint, plating, and chromate. 

Magnesium alloys are a sustainable material option that offer an environmentally-friendly alternative to plastics. The scrap material from magnesium parts is 100% recyclable and can be re-casted like raw material, making it an ideal choice for manufacturers who prioritize responsible and sustainable production methods.

Comparision of Magnesium, Aluminum, and Zinc Die Castings

(1 is the highest rating)

Magnesium (AS91D)

Aluminum (A380)

Zinc

(Zinc #3)

Strength-to-Weight Ratio

1

2

3

Material Cost/Volume

2

1

3

Machinability

1

2

3

Die Life

2

3

1

Density

2

1

3

Ability to Cast Thin Walls

2

3

1

Magnesium Casting Finishing

 Various finishes can be applied to the magnesium die cast parts. Some of the finishes are strictly for aesthetic purposes, while others also serve protective functions.

  • Smoothing and Polishing. The parts are smoothed and polished to improve the surface quality and aesthetics. Smoothing and polishing may affect the part dimension by removing a little bit of material.
  • Bead blasting. The surface of the part is blasted with small glass beads to smooth the surface and protect it from corrosion. It is excellent for adding a uniform matte finish, where dimension tolerance is not a key concern.
  • Anodizing adds a thin ceramic layer to the surface of the part to protect it from corrosion and wear. Only certain materials can be anodized, for example, aluminum and titanium.
  • Powder coating. Powder coating adds a thin layer of polymer to protect the surface from wear. The coating is wear-resistant and can be added multiple times to improve protection. Powder coating can also be combined with bead blasting to increase corrosion resistance. This finish is excellent for CNC machined parts requiring high impact strength or for parts that cannot be anodized
Magnesium Die Casting with powder coating outside

Applications of Magnesium Die Castings

magnesium die casting with powder coating and vents

The medical, electronic, automotive, and aerospace industries widely utilize magnesium for their die-casted components due to its unique properties. If you have a project that could benefit from magnesium die-casting, we welcome you to contact us today. Our team of experts is ready to help you explore the exceptional benefits of this remarkable material. 

With many magnesium die casting processes in our network, Amfas offers a wide range of options. Amfas’ use of the best people and equipment for the job at hand allows for tight tolerances in any production part that we fabricate. With over 20 years of casting experience, our team will ensure your parts are made with outstanding magnesium die-cast machine companies.