In the modern manufacturing industry, choosing the right die casting machine is crucial to improve product quality, production efficiency and reduce production costs. Especially for magnesium alloy, which has unique properties and wide application prospects, it is particularly important to choose a suitable die-casting machine. Based on the material characteristics, this paper introduces in detail how to choose a die-casting machine suitable for magnesium alloy die-casting.

1、The characteristics of magnesium alloy and its requirements for die casting machines

As one of the lightest metal structural materials, magnesium alloy has the advantages of low density (about 2/3 of aluminum and 1/4 of steel), high specific strength, good damping and good machinability. At the same time, magnesium alloy also has good thermal conductivity, electromagnetic shielding and dimensional stability, so that it is widely used in automotive, aerospace, 3C products and other fields. However, magnesium alloy is easily oxidized and flammable in air, and liquid magnesium is easy to react with oxygen to produce magnesium oxide at high temperatures, which puts forward higher requirements for die casting machines.

2、The classification and characteristics of die casting machine

Die casting machine is usually divided into hot chamber die casting machine and cold chamber die casting machine according to the working state of its press chamber. The press chamber of the hot chamber die casting machine is immersed in the liquid metal in the thermal insulation crucible, and the injection mechanism is installed above the thermal insulation crucible; The body of the cold chamber die casting machine is separate from the heat preservation furnace. During die casting, the metal liquid is taken out of the heat preservation furnace and injected into the mold cavity. The cold chamber die casting machine is distinguished according to the position of its press chamber and injection mechanism, the press chamber and injection position in a horizontal position is called a horizontal cold chamber die casting machine, the press chamber and injection mechanism in a vertical position is called a vertical die casting machine, and the vertical injection and vertical direction of the die casting machine is called a full vertical die casting machine.

2.1、Characteristics of hot chamber die casting machine

Simple structure: easy to operate, easy to achieve automated production.

High production efficiency: no casting procedure is required, the process is simple.

Less metal loss: less heat loss, metal liquid is always in the closed channel, oxidizing inclusions are not easy to get involved, and the casting quality is good.

Short life: hot working parts such as pressure chamber, punch, gooseneck tube and nozzle have short life and are not convenient to replace.

Small scope of application: due to poor oxidation resistance, it is mainly used for die-casting zinc, tin, lead and other low melting point alloys and small thin-walled magnesium alloy die-casting parts, and the closing force is usually less than 650T.

2.2、Characteristics of cold chamber die casting machine

Comprehensive specifications and models: wide range of adaptation to product size and alloy types.

High production efficiency: the production operation is simple, and the automatic production can be realized online with the automatic peripheral equipment.

Easy segment control: The segmented control and adjustment of the injection stroke are easy to achieve, and the die casting process can meet different requirements.

Large heat loss: the heat loss of liquid metal in the injection process is large, and the liquid metal is easily involved in oxidizing inclusions and air in contact with the air.

Special process requirements: Special processes must be taken for products with high density or requiring heat treatment.

2.3、Characteristics of vertical die casting machine

Less gas involved: less gas involved in metal hydraulic shooting process.

Easy to set up: easy to set up in the central casting system.

Maintenance trouble: maintenance and operation trouble, there are cutting and cake rolling procedures in the production process, low production efficiency.

Limited application: mainly small and medium machines, less consumption in the production process, currently mainly used for die-casting production of special products such as motor rotors.

3、The key factors to choose a die-casting machine suitable for magnesium alloy die-casting

3.1、Consider the oxidation characteristics of magnesium alloy

Magnesium alloys are easily oxidized at high temperatures, so cold chamber die-casting machines should be given priority when choosing a die-casting machine. The press chamber of the cold chamber die casting machine is separated from the holding furnace, reducing the chance of liquid metal coming into contact with the air and reducing the risk of oxidation. In addition, cold chamber die casting machines can further reduce the possibility of oxidation by vacuuming and filling with nitrogen.

3.2、 Assess productivity needs

Different magnesium alloy die castings have different requirements on production efficiency. For example, for castings requiring high efficiency production such as large magnesium alloy wheels, horizontal cold chamber die casting machines with large closing force should be selected, such as 900T to 1200T equipment. For some small, thin-walled magnesium alloy castings, hot chamber die-casting machines can be considered, but attention should be paid to the limitation of its antioxidant capacity.

3.3、 Analyze product quality requirements

For magnesium alloy castings requiring high density or requiring heat treatment, cold chamber die casting machines with special process processing capabilities should be selected. In addition, attention should also be paid to the injection performance of the die casting machine, including low-speed performance, acceleration performance and pressurization performance, to ensure the internal quality and appearance quality of the casting.

3.4、 Consider cost

Under the premise of satisfying product quality and production efficiency, the acquisition cost, operating cost and maintenance cost of the die-casting machine should be considered comprehensively. For example, although the hot chamber die casting machine has a simple structure, easy operation and relatively low price, its hot work life is short and frequent replacement may increase the operating cost. Although the initial investment of cold chamber die casting machine is high, its wide range of application, long service life and easy maintenance may be more economical.

3.5、 Understand the manufacturer’s technical support and after-sales service

When purchasing a die casting machine, you should also understand the technical support and after-sales service of the manufacturer. High-quality technical support can help users better grasp the use of die casting machine and maintenance skills; Timely after-sales service ensures that problems encountered during the production process can be quickly resolved to reduce downtime and losses.

4、 Conclusion

It is a complicated and important process to choose a die-casting machine suitable for magnesium alloy die-casting according to the material characteristics. Through in-depth understanding of the characteristics of magnesium alloys and the advantages and disadvantages of different types of die casting machines, as well as comprehensive evaluation and selection according to specific needs, the most suitable equipment configuration scheme can be found to ensure the maximization of product quality and production efficiency as well as the optimal control of cost.