1. Die casting is to melt non-ferrous metals and let them flow into mold under pressure. Because molds are used, it is suitable for mass production. Unlike other casting methods, die casting requires pressure, so it has excellent dimensional accuracy. In addition, since molds are used instead of sand molds, surface of finished product is smooth.
2. Die casting is suitable for complex shapes that are difficult to process with sheet metal processes, or products that cannot use resin materials due to insufficient strength. Since complex three-dimensional shapes can be processed, it has characteristics of higher degrees of freedom than sheet metal processes and higher yields than cutting processing.
3. However, it cannot be used to process pipes and hollow shapes. In addition, due to use of molds, it is not suitable for shapes that protrude inwards such as overhangs and shapes such as holes on the side.
4. Die casting mainly uses aluminum alloys, zinc alloys, magnesium alloys, copper and other materials. Aluminum alloys and zinc alloys are the most widely used.

 

1. Aluminum alloy die casting: Aluminum die castings are very light, stronger than zinc die castings, and have less dimensional changes after long-term use. Therefore, they are widely used in many parts such as automobile gearbox housings. In addition, due to its good thermal conductivity, it is also used for housings that also serve as heat sinks.
2. Zinc alloy die casting: Zinc die castings are heavier than aluminum die castings and have low strength. However, its processability is very good, it can produce more complex and high-precision parts than aluminum die castings. It is suitable for manufacture of parts with low strength requirements and beautiful shapes. It is often used to manufacture automotive parts and structural parts of industrial machinery. In addition, because it is easy to perform surface treatment, it is also used to manufacture furniture handles, etc.
3. Dimensional accuracy of die-casting products is relatively high for casting, but not high compared to cutting. Therefore, in many cases, before assembly, mating surfaces between die-cast parts, mounting locations for other parts, fastening surfaces of screws, and other locations are pre-cut or ground.

 

Die casting process, which is excellent in mass production and easy to process into complex shapes, also has its disadvantages.
1. Compared with cutting, strength of finished product is lower even if same material is used. When molten metal is allowed to flow under pressure, problems such as air mixing will occur, and even if same aluminum or zinc material is used, strength of manufactured parts will be lower than that of processes such as cutting. Although there are improvement methods such as making mold in a vacuum state when injecting molten metal, it is very costly to completely improve this problem.
2. High initial cost. Die casting must use a mold and must inject molten metal, so production equipment is expensive. Therefore, if there is no expectation of large-scale mass production like automobiles, corresponding initial investment may not be obtained.

 

In short, die casting process is mainly used for aluminum die castings and zinc die castings. Aluminum die castings are light, strong, and easy to conduct heat. Zinc die castings have characteristics of good processability and high dimensional accuracy.