Aluminum die casting is a type of pressure casting part. It is a pressure casting mechanical die casting machine with a casting mold installed. The aluminum or aluminum alloy heated to a liquid state is poured into the feed port of the die casting machine, and then the die casting machine performs die casting to cast aluminum parts or aluminum alloy parts whose shape and size are limited by the mold. This kind of part is often referred to as aluminum die casting.

Die casting is a high-pressure and high-speed injection of molten metal that can manufacture thin-walled parts with complex shapes. The resulting casting grain is fine, the structure is dense, the strength is high, and the die-casting productivity is high. Therefore, die-casting parts are widely used in automobiles, computers, communication filters, medical equipment and other manufacturing industries, such as central control dashboards, motor boxes, steering systems, laptop shells, dual-cavity filters and other parts.

Advantages of aluminum die casting applications:

(1) It can manufacture metal parts with complex shape, clear contour and thin wall and deep cavity. Because molten metal maintains high fluidity at high pressure and speed, it is possible to obtain metal parts that are difficult to machine with other process methods.

(2) The dimensional accuracy of die castings is high, up to IT11-13 level, sometimes up to IT9 level, surface roughness is Ra0.8-3.2 m, good interchangeability.

(3) High material utilization. Due to the high precision of die castings, they can be assembled and used with only a little processing, and some die castings can be directly assembled. Material utilization is about 60%-80% and billet utilization is 90%.

(4) High production efficiency. Due to the fast filling speed of aluminum die castings, the filling time is short, the metal solidifies quickly, and the cycle speed of die casting operation is fast. Among the various casting processes, die casting is more productive and suitable for mass production.

(5) The plug-in is easy to use. It is easy to set the positioning mechanism on the die casting mold, which is convenient for the inlay casting of the insert and meets the local special performance requirements of the die casting.

Zinc alloy die-casting has the advantages of forming complex geometric parts at one time, simple processing technology, high production efficiency and saving metal materials. At the same time, its surface accuracy and mechanical strength are high, the appearance is smooth and dense, and there are few or no chips during processing, so it has been widely used in national defense, transportation, electronics, construction, daily hardware, especially the automobile industry and other fields.

Zinc-aluminum alloy containing 22% aluminum (mass fraction) shows extraordinary plasticity at a certain temperature, and has wonderful softening and abnormal elongation functions, so it is called a superplastic material. The surface of zinc alloy die casting is a dense layer without pores, and the structure of more than 165 pores under the surface is loose, which brings difficulties to its surface treatment and makes it have special requirements for mechanical polishing. In addition, during the die casting process, the part changes from a molten state to a solid state. Due to the different freezing points of cooling, segregation tends to occur on the surface of die castings, and aluminum-rich or zinc-rich phases will occur in some parts of the surface. The shape of zinc alloy die castings is generally more complex, and the chemical properties of aluminum and zinc are very active. It is easy to react with acids, alkalis and oxygen in the air, resulting in rapid oxidation, passivation and corrosion of the surface, which brings difficulties to electroplating.