Comprehensive analysis of die-casting

Although most people may not directly perceive die casting, the products it produces play an important role in our daily lives. Now, you may be surrounded by various die-cast products, such as metal handles for drawers and wardrobes, bathroom faucets, valves, etc. Die casting provides strong, durable and high-performance solutions for the manufacturing of various products. This process improves the quality and lifespan of products and makes our lives more convenient. So, let’s explore the wonderful capabilities of die-casting!

What is die casting

Die casting is a manufacturing process in which molten metal is injected into a high-pressure mold to quickly solidify and form the desired part. It is also known as pressure casting or pressure casting method.

In the die casting process, metal materials (usually aluminum alloys, zinc alloys, magnesium alloys, etc.) that are heated to melt are injected into a designed casting mold, and then high pressure is used to force the metal to fill the space in the mold. Finally, after cooling and After solidification, the parts or products to be manufactured can be formed.

Two processes of die casting

There are two process branches of die casting, namely cold chamber die casting and hot chamber die casting. Cold chamber die casting is suitable for high melting point metals, and hot chamber die casting is suitable for the die casting process of low melting point metals.

Cold chamber die casting

Cold chamber die casting

Cold chamber die casting is a die casting process suitable for high melting point metal alloys such as aluminum alloys and copper alloys.

In this process, the molten metal for the mold is stored in an external furnace and an injection column is used to inject the molten metal into the mold cavity.

Cold chamber die casting is suitable for situations where high pressure is required to ensure that the metal fully fills the mold cavity, and is also suitable for products requiring high precision and surface quality.

Hot chamber die casting

Hot Chamber Die Casting

Hot chamber die casting is suitable for low melting point metal alloys, the most common being zinc alloys and magnesium alloys.

In this process, the molten metal is usually held in an internally heated furnace, eliminating the need for an external furnace. Through an injection column, molten metal is injected into the mold cavity without loading the metal from the outside.

Hot chamber die casting is generally suitable for producing smaller parts because injection pressures are typically lower, as well as for applications that require high productivity and cost-effectiveness.

Three types of die casting

The three types of die casting are high pressure die casting and gravity die casting as well as low pressure die casting.

High-pressure die casting is a die-casting process commonly used to manufacture thin-walled parts, using higher injection pressures;
Gravity die casting is a process that uses gravity to fill the mold cavity, usually used for large castings;
Low-pressure die casting is a process that uses lower injection pressure and is suitable for manufacturing large, thick-walled parts.

High pressure die casting


One of the key features of the high-pressure die casting process is the use of higher injection pressures.

Injection pressure refers to the force required to push molten metal into the mold. By using high pressure, it is ensured that the molten metal can quickly fill the entire mold cavity, including intricate details and thin-walled parts, which are usually between 1mm-5mm thick and sometimes even thinner.

The parts produced in this way can reduce weight while maintaining strength. Only high-pressure die casting can meet these requirements.

Gravity die casting


Gravity die casting uses gravity to fill the mold cavity with metal alloy without the use of pressure.

In the gravity die casting process, the mold cavity is usually in a vertical position, and once the metal alloy is poured into the mold cavity, gravity causes the metal to fill the entire cavity.

Because only gravity acts, the metal injection speed is slower and the production cycle becomes longer. Therefore, gravity die casting is generally used to manufacture large parts or products with larger wall thicknesses.

Low pressure die casting


Low-pressure die casting is characterized by the use of lower injection pressure to fill molten metal into the mold cavity.

In the process of low-pressure die-casting, although the pressure used is lower than that of high-pressure die-casting, a certain amount of pressure is still needed to push the metal injection.

It is suitable for producing parts or products of medium size and complexity.

Die casting steps

The steps of die casting include mold design, melting metal, injecting metal, cooling and solidification, mold opening, part removal, surface treatment, etc. Here is a brief introduction:

Mold design

In this step you need to design a mold for the part or product you want to make. (A casting mold is also called a mold. A mold usually consists of two parts, an upper mold and a lower mold, which can be separated to facilitate metal injection and part removal.)

Molten metal

In this step you need to prepare the metal alloy raw material (usually aluminum alloy and zinc alloy) and heat it to a liquid state. (The melting point of aluminum alloy is 660°C, and the melting point of zinc alloy is between 419°C and 420°C)

Injection metal

In this step, the molten metal alloy is injected into the casting mold, but you only need to control the injection system of the die-casting machine to do it automatically.

Cooling and solidification

There is nothing more to do at this step, the only thing is waiting. Once the metal has filled the mold cavity and formed the desired shape, the mold is cooled, allowing the metal to gradually solidify into the solid part we want to produce.

Open and take out

In this step, you need to open the cooled mold and remove the solidified metal parts. (It should be noted that despite cooling, the mold and the metal parts inside are still very hot. You need to use tools to open the mold and remove the parts. Do not use your hands directly to operate.)

Surface treatment

Finally it’s the last step! In order to make the final parts or products beautiful, you also need to perform some surface treatment work, such as deburring, trimming, grinding, drilling, threading, etc. This completes the complete die-casting step!

Die casting, casting, sand casting and forging

Die casting, casting, sand casting and forging are different metal working processes. Die casting is a process for manufacturing complex, high-precision parts, casting is the oldest method and is used for manufacturing products of all sizes, sand casting focuses on small batches and large parts, and forging creates high-strength parts through heating and deformation.

Advantages and Disadvantages of Die Casting


●High precision and complexity
●High production efficiency
●Good surface quality
●Material diversity
●High strength and lightweight


●Mold manufacturing cost is high
●High initial investment
●Design constraints
●Cooling time
●Possible formation of pores

Products manufactured by die casting

application scenario

The die-casting process is widely used to manufacture a variety of products and components, including automotive engine parts, electronic equipment casings, industrial equipment, household appliances, power industry components, aerospace parts, and some daily consumer products.

Auto parts: automobile engine parts (such as cylinder head, cylinder block), transmission parts, braking system components, suspension parts and body structures, etc.
Electronic Equipment Housings: Housing components for computers, cell phones, tablets and cameras.
Industrial components: pumps, valves, hydraulic and pneumatic components, etc.
Household Appliances: Parts for refrigerators, washing machines, dishwashers and microwaves.
Power industry parts: cable joints, battery boxes and transformer housings.
Aerospace parts: high-precision parts such as aircraft engine parts, avionics components and satellite components.
Consumer products: bicycle parts, door handles, faucets and lamps, etc.

Materials and commonly used models suitable for die casting

The die-casting process is suitable for a variety of materials, including aluminum alloys, zinc alloys, magnesium alloys, copper alloys, cast iron and other alloys.

Commonly used models of aluminum alloys: A380, A383, A360.
Commonly used models of zinc alloys: Zamak 3 and Zamak 5.
Commonly used magnesium alloys models: AZ91D and AM60B.
Commonly used models of copper alloys: copper-aluminum alloys and copper-tin alloys.
Commonly used models of cast iron: gray cast iron and ductile iron.

Are die castings expensive

Die casting is more expensive than some other casting methods because die casting requires the manufacture of complex molds, which are expensive to make, and die casting is suitable for mass production and therefore may not be cheap enough for low-volume production.

Alternatives to die casting

Alternatives to die casting include a variety of casting and manufacturing methods such as sand casting, investment casting, powder metallurgy, injection molding, forging, 3D printing, and spin casting.

Sand Casting: Sand casting is a traditional casting method that uses sand molds to create parts. Sand casting is relatively low-cost and suitable for low-volume production and large-scale component manufacturing.

Investment Casting: Investment casting is a method of manufacturing parts with high precision and complex geometry. It uses wax molds and is suitable for products that require high precision and exquisite surfaces.

Powder Metallurgy: Powder metallurgy is a method of pressing metal powder into shape and then sintering it to make parts. It is suitable for manufacturing complex metal parts, especially precision components.

Injection Molding: Injection molding is typically used for plastic products, but can also be used for metal powders or ceramics. It is suitable for manufacturing small parts in large quantities.

Forging: Forging is a method of heating metal and shaping it through pressure. It is suitable for manufacturing high-strength and high-quality parts.

3D Printing: 3D printing technology can manufacture complex metal parts and is suitable for rapid prototyping and small batch production.

Spin Casting: Spin Casting is suitable for manufacturing small precision parts, especially jewelry and model making.


This article provides a comprehensive analysis of die casting. I hope you will gain something after reading it.

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