Die casting is a metal casting process characterized by the use of a mold cavity to apply high pressure to the molten metal. Molds are usually machined from higher strength alloys, some of which are similar to injection molding. Most die castings are iron-free, such as zinc, copper, aluminum, magnesium, lead, tin, and lead-tin alloys, as well as alloys thereof.
The traditional die casting process consists of four steps, or high pressure die casting. These four steps include mold preparation, filling, injection, and falling sand, which are also the basis for various improved die casting processes.
Advantages and disadvantages
Advantages:
1、The advantages of die casting include the excellent dimensional accuracy of the casting.
2、Compared to other casting processes, its castings have a smooth surface with a fillet radius of approximately 1-2.5 microns.
3、It can directly cast internal structures such as wire sleeves, heating elements, and high-strength load-bearing surfaces.
Disadvantages:
1、The biggest drawback of die casting is the high cost.
2、This process is only suitable for metals with higher fluidity, and the casting quality must be between 30 grams and 10 kilograms.
3、In the usual die casting, the final casting of a batch of castings always has voids. Therefore, no heat treatment or welding can be performed because the gas in the slit expands under the action of heat, resulting in internal micro defects and peeling of the surface.
Characteristics
1、The molten metal fills the cavity under pressure and crystallizes and solidifies at a higher pressure. The common pressure is 15-100 MPa.
2、The metal liquid fills the cavity at high speed, usually at 10-50 m/s, and some can also exceed 80 m/s (the line speed of the cavity introduced into the cavity through the ingate), so the filling time of molten metal is extremely short, and the cavity can be filled within about 0.01-0.2 seconds (depending on the size of the casting).
Status quo
At present, the competition in China's die-casting industry is still not standardized, which will have an impact on the development of the die-casting industry. The main problems include:
First, some operators purchase die-casting of factory-named sites, print famous brands and certificates of well-known manufacturers, and cause serious damage to the reputation of qualified die-casting enterprises.
Second, refurbished die-casting, some operators passed the second sale after re-painting of waste die-casting, which brought serious damage to the quality of the project.