How to Choose Die Casting Technology? How to Collaborate with CNC and Laser Cutting?

The precision manufacturing industry is entering a new phase of high-quality development. As a core metal forming process, die casting is widely used in various fields—including automotive, aerospace, and electronics—thanks to its outstanding advantages of high efficiency and precision. Working in tandem with complementary services such as CNC machining, Laser Cutting, and sheet metal forming, it is driving the upgrading of the manufacturing industry chain. This article systematically outlines the key aspects of die casting technology while analyzing the current state of related processing services, with the aim of providing a reference for industry professionals.

 

 

Die casting is an advanced metal casting process. Its core principle involves rapidly injecting molten metal (such as aluminum, zinc, or magnesium alloys) into precision molds under high pressure. After rapid cooling and solidification, this process produces metal parts with complex geometries, high dimensional accuracy, and excellent surface finish. Compared to traditional casting processes, die casting typically eliminates the need for complex post-processing and can directly produce finished or semi-finished products that meet precision requirements, making it the preferred solution for high-volume metal part manufacturing. Among these, Aluminum Die Casting (Aluminum Die Casting), with its lightweight and corrosion-resistant properties, has become one of the most widely used types of die casting today.

 

 

The working principle of die casting can be summarized into four core steps: “melting—high-pressure injection—cooling—demolding.” The entire process relies on specialized die casting equipment and precision molds, with the specific workflow as follows:

 

Mold Preparation: Before die casting, the Casting Mold is cleaned, lubricated, and sprayed with a release agent to reduce mold wear, ensure smooth demolding of the casting, and extend the mold’s service life.

 

Metal Melting: Metal raw materials such as aluminum alloys and zinc alloys are placed in a furnace and heated until molten. This ensures the molten metal is uniform and free of impurities, meeting the requirements for forming.

 

High-Pressure Injection: Utilizing the hydraulic system of the die-casting machine, molten metal is injected into the mold cavity at high pressure (typically 20–70 MPa) and high speed. This allows the molten metal to fully fill every detail of the cavity, meeting the forming requirements for complex parts.

 

Cooling and Solidification: The molten metal rapidly cools within the mold, forming a solid casting that matches the cavity’s shape. Cooling channels within the mold accelerate the cooling process, improving production efficiency.

 

Demolding and Finishing: After the casting solidifies, the die-casting machine opens the mold, and the casting is removed via an ejection mechanism. Excess material, such as flash and burrs, is then removed. For castings requiring high precision, further refinement can be achieved through CNC machining.

 

 

Based on differences in metal melting methods, injection pressure, and mold structure, die casting is primarily divided into the following four categories, each suited to different materials and production scenarios:

 

Hot-chamber Die Casting: Suitable for low-melting-point metals such as zinc, tin, and magnesium alloys. The die-casting machine incorporates an integrated furnace, with molten metal directly fed into the injection system. It features short production cycles (over 15 cycles per minute) and is suitable for high-volume production of small to medium-sized parts, such as valves and electronic components.

 

Cold-chamber Die Casting: Suitable for high-melting-point metals such as aluminum and copper alloys. The furnace is separate from the die-casting machine, and molten metal must be manually or automatically ladled into the injection chamber. With higher injection pressure, this method is suitable for producing large, high-strength parts such as automotive engine blocks and transmission housings, and is currently the most widely used type of die casting.

 

Vacuum Die Casting: The mold cavity is evacuated to remove air before molten metal is injected, thereby reducing casting porosity and improving mechanical properties. This method is suitable for parts with high precision and strength requirements, such as those used in aerospace and medical devices.

 

Gravity Die Casting: Molten metal is poured into the mold using gravity. This process is simple and cost-effective, making it suitable for small to medium-volume production. The surface finish of the parts is superior to that of Sand Casting and is commonly used for automotive pump bodies, housings, and similar components.

 

 

Compared with traditional casting and mechanical cutting processes, die casting, with its unique forming method, demonstrates the following significant advantages and has become an important support for large-scale manufacturing in the industry: 

 

High Production Efficiency: Each die-casting cycle only takes a few seconds to tens of seconds, enabling large-scale continuous production and significantly reducing the cost per piece. It is particularly suitable for orders of over 100,000 pieces. 

 

High precision and surface quality: The dimensional accuracy of the castings is high, with tolerances controllable within ±0.1 mm, and the surface finish can reach Ra 1.6–6.3 μm. There is no need for complex subsequent grinding, reducing processing steps. 

 

Wide material compatibility: It can process various non-ferrous metals such as aluminum alloy, zinc alloy, and magnesium alloy. Among them, aluminum alloy die-casting is widely used in lightweight manufacturing due to its light weight and high strength. 

 

Strong molding capability: High-pressure injection can achieve one-time molding of thin-walled and complex geometric shape parts, solving the problem of difficult processing of complex structures by traditional processes, such as irregular shells and precision gears. 

 

Cost controllable: Under large-scale production, the mold cost can be evenly distributed, and the material utilization rate is high. Compared with cutting processes such as CNC Milling , it can reduce material waste and lower the overall production cost. 

 

 

With the continuous upgrading of die casting technology, its application fields have been continuously expanding, covering multiple core manufacturing industries such as automobiles, aerospace, electronics, and home appliances, and has become the mainstream processing method for key parts. 

 

The Automotive Industry: accounting for over 60% of the total die-casting applications, it is mainly used to produce engine blocks, transmission cases, steering brackets, wheel hubs and other parts. Among them, aluminum die-casting parts help achieve lightweighting of automobiles and reduce energy consumption. 

In the aerospace industry, it is used to manufacture fuselage structural components, auxiliary engine parts, etc. The castings are required to have high strength and low porosity. Vacuum die casting or cold chamber die casting processes are mostly adopted. 

The Electronics Industry: Producing precision parts such as mobile phone frames, notebook computer shells, and camera brackets. Relying on the high precision and efficiency of die-casting, it meets the demands of miniaturization and lightweighting in electronic products. 

Household appliances industry: Producing parts such as washing machine inner drums, air conditioner compressor shells, and refrigerator door handles, with a focus on both practicality and aesthetics, to enhance the durability of household appliances. 

 

Other Fields: including medical devices, hardware accessories, furniture, etc. For instance, precision brackets in medical devices and metal legs in furniture all rely on die-casting technology for mass production. 

 

 

Although die casting has prominent advantages, it still has certain limitations due to process characteristics and equipment constraints, which need to be addressed through technological upgrades and process coordination. 

 

High Initial Investment: The design and manufacturing costs of die-casting machines and precision casting molds are relatively high, making it difficult for small and medium-sized enterprises to afford. It is suitable for large-scale production, and the economic efficiency of small-batch orders is relatively poor. 

Material limitations are obvious: it is only applicable to non-ferrous metals and cannot process high-melting-point black metals such as steel, which restricts its application in the field of heavy machinery. 

 

There is a Risk of Porosity in Castings: If the injection pressure is insufficient or the mold design is unreasonable, the castings are prone to defects such as gas holes and shrinkage cavities, which affect the strength of the parts. Optimization can be achieved through processes such as vacuum die casting. 

The molds wear out quickly: Due to long-term exposure to high-temperature and high-pressure environments, molds are prone to wear and deformation, requiring regular maintenance and replacement, which increases subsequent operation and maintenance costs. 

 

Insufficient Design Flexibility: Once the mold is formed, it is difficult to modify the structure of the parts. If the product design undergoes an iteration, it usually requires the remanufacture of the mold, which is time-consuming and labor-intensive. 

 

 

Currently, die casting is not an isolated process but is deeply integrated with various processing services such as CNC milling, laser cutting services, Sheet Metal Bending, and CNC Turning, forming a full-chain service model of "die casting + precision machining + surface treatment". This approach compensates for the limitations of die casting, enhancing the precision and added value of parts. 

 

For instance, for high-precision required die-cast parts, key areas can be finely processed through high-precision CNC milling to ensure tolerances reach the micrometer level; for sheet metal parts with complex shapes, Sheet Metal Laser Cutting and precision sheet metal bending can be combined for assembly with die-cast parts; for parts that need to be spliced, Sheet Metal Welding service can achieve precise connection, enhancing the overall integrity of the product. 

 

Industry insiders point out that in the future, die-casting technology will evolve towards large-scale integration, intelligence and greenness. By optimizing mold design and enhancing equipment precision, it will gradually solve pain points such as porosity and mold wear. Meanwhile, strengthening collaboration with various precision processing services will further expand the application boundaries of die-casting and inject new impetus into the high-quality development of manufacturing.