What Is Aluminum Die Casting?

This article explains in detail the definition, alloys, machine, mold, process, design guide, applications, etc. of aluminum die casting. Click to learn more!
aluminum die casting process


Aluminum die casting is a high-efficiency, high-precision metal forming process, widely used in various industries. Liquid aluminum alloy is injected into a precision mold cavity through high pressure, cooled and solidified under pressure to form a casting of the desired shape. This process can produce aluminum die casting parts with complex structure, high precision and excellent performance, which is an indispensable part of modern manufacturing industry.

Aluminum Die Casting Machine

When we talk about aluminum die casting machines we generally mean cold chamber die casting machines. Because of the high melting point of aluminum, 660°C, we need to use a separate crucible to heat and melt the aluminum alloy. Then the melted aluminum alloy is scooped into the injection cylinder and injected into the mold cavity using high pressure.

cold chamber die casting machine
aluminum cold chamber die casting machine

In hot chamber die casting, the furnace and the machine are connected together, and only metals with low melting points such as zinc, tin and lead can be selected. If the high melting point aluminum alloy is put into the hot chamber die casting machine, it will greatly harm the machine.

Aluminum Die Casting Mold

Aluminum die casting can form all kinds of precision parts, thanks to the die casting mould. Because the mold determines the shape, tolerance, surface finish, mechanical properties of aluminum die casting parts. Aluminum die casting molds are generally CNC machined from steel that can be heat treated, such as H13. Being able to independently make die casting molds is a priority when you are looking for an aluminum die casting manufacturer.

Aluminum Die Casting Alloys

Die casting aluminum alloys have excellent casting properties, we use different aluminum alloys to provide precision aluminum die casting products for different industries. Die casting aluminum alloys can be classified into the following 4 series according to the main elements added:

Al-Si Alloys

Aluminum-Silicon alloys have a silicon content of 4% to 13%. al-Si alloys have the best casting performance, it has good corrosion resistance, airtightness, and adequate mechanical properties and welding performance. It is the most varied and most used die-casting aluminum alloy.

Al-Cu alloy

Aluminum-Copper alloy is the earliest casting aluminum alloy, has high strength and thermal stability, but poor corrosion resistance. After appropriate addition of manganese and titanium, Al-Cu alloy can significantly improve the strength and casting performance at room temperature and high temperature.

Al-Mg Alloy

Aluminum-Magnesium alloy is the cast aluminum alloy with the lowest density but high strength. It has excellent corrosion resistance and mechanical properties.

Al-Zn Alloy

Aluminum-Zinc alloys have high strength, good corrosion resistance and high temperature stability, making them ideal for the manufacture of ships, aircraft, trains, motorcycles and automobiles.

In general, different die-casting aluminum alloys have different characteristics and applications, and choosing the right casting aluminum alloy can make the product more to meet the design requirements. Commonly used die-casting aluminum alloys are: A356, A360, A380(ADC10), A383(ADC12), AlSi9Cu3, and AlSi10Mg.

Aluminum Die Casting Process Steps

Design Stage

  • Mold design
  • Process parameter setting
  • Design mold and die-casting parameters based on 2D/3D drawings. This is the first and most important step.

Preparation Stage

  • Mold preheating and inspection
  • Heating and melting aluminum alloy

Die Casting Stage

  • Closing the mold: The two halves of the mold are tightly closed to form a complete cavity. This step is an important step to ensure the accuracy of the casting, because only when the mold is completely closed can the liquid aluminum alloy not spill out.
  • Pouring: Injecting liquid aluminum into the mold cavity. The pouring speed and temperature need to be controlled during the pouring process to prevent oxidation or pores.
  • Injection: Under high pressure, liquid aluminum alloy fills the mold cavity at high speed.
  • Opening the mold: The mold separates and the formed casting falls off. This step requires controlling the mold opening speed and angle to ensure that the casting will not be damaged by falling off too fast or too slow.
  • Core pulling and ejection: For some castings with complex structures, core pulling and ejection operations may be required. Core pulling is to extract the core rod from the mold, while ejection is to use an ejector pin to eject the casting from the mold.
  • Removal: The finished casting is removed from the mold. Once removed, the casting should be inspected to ensure there are no obvious defects in the part.

Post-processing Stage

  • Clean burrs and detect dimensions
  • Surface treatment such as shot blasting, sandblasting, polishing, powder coating, and baking paint.
  • Packaging and delivery

Advantages and Defects of Aluminum Die Casting

Advantages of aluminum die casting

  • High efficiency: The aluminum alloy liquid quickly fills the mold cavity under high pressure. It can die-cast 70-100 times per hour.
  • High precision: Aluminum die casting can form high-precision parts with complex shapes, thin walls and deep cavities, and uniform dimensions.
  • Cost-effective: When producing aluminum parts in large quantities, aluminum die-casting can greatly reduce the cost per unit product.
  • Wide application: Aluminum die-casting can provide precision aluminum die-casting components for automobiles, electric vehicles, motorcycles, aerospace, medical equipment, telecommunications and other industries.

Defects of aluminum die casting

There is no perfect casting process in the world. Although aluminum die-casting has many advantages, it also has some defects, such as shrinkage cavities, cracks, cold shuts, flow marks, etc. However, what is exciting is that there is an emerging, more advanced die-casting process that can effectively eliminate these defects. This process is squeeze casting. Squeeze cast parts can also be heat treated to further improve the mechanical properties of the part.

Aluminum Die Casting Applications

Automotive Industry

  • Engine components
  • Suspension components
  • Body structure parts
  • Heat treatment system components

New Energy Industry

  • Parts housings
  • Heat sinks
  • Brackets, structural components

Aerospace Industry

  • Aircraft structural components
  • Engine components
  • Precision instrument components

Other Industries

  • Medical device manufacturing
  • Household
  • Sports equipment
  • Power Equipment

Aluminum Die Casting Products

Here are some parts made by SANON, a professional aluminum die casting manufacturer. If you are looking for a reliable aluminum die casting company, SANON will be a good choice.

Aluminum Die Casting Design Guide

Die casting design is the first step in the die casting process. Whether the design is reasonable directly affects whether the die-casting work can proceed smoothly. When you are designing a die cast part, be sure to consider the following:

Simplify the casting structure. Eliminate inner concavities, avoid or reduce core-pulling parts, and ensure smooth demoulding of die-casting parts. At the same time, product and mold costs can be reduced.

Reasonably design the wall thickness of die castings. If the wall thickness is too thin, filling will be difficult and poor filling will easily occur. If the wall thickness is too thick, defects such as shrinkage cavities and pores are prone to occur, which greatly reduces the mechanical properties of the casting.

Minimize die casting tolerances. In order to meet the performance of the part, try to use loose die-casting tolerances, because strict tolerances will increase the cost of the part.

Try to avoid CNC machining. CNC machining will destroy the dense layer on the surface of the part and affect the mechanical properties of the part. It will also increase costs.

Design draft angle. This can reduce the friction between the casting and the mold cavity, make it easier to remove the casting, and extend the life of the mold.


In this paper, the aluminum alloy die casting process has been discussed in depth from multiple dimensions, through these analyses, we can see that aluminum alloy die casting as an important metal forming technology, plays an irreplaceable role in modern manufacturing industry. With the progress of technology and changes in social demand, aluminum die casting will become more intelligent, environmentally friendly and efficient, so as to provide more quality products and services for human production and life.

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Eric Zhou

Focus on providing squeeze casting, aluminum die casting(hpdc+lpdc), mold making, CNC machining, and sheet metal fabrication solutions. If you need help, please feel free to contact us!

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