Die Casting

2022-05-17

1.Introduction of die casting

Die casting is a process to fill metals or alloys in liquid or semi-solid form into the cavity of a die-casting mold at a high speed under high pressure, and making the metal or alloy to form a casting. The pressure commonly used in die casting is 4-500MPa, and the metal filling speed is 0.5-120m/s. Therefore, high pressure and high speed are the fundamental difference between die casting and other casting methods, and are also important features.

2.Advantage of die casting

-High productivity, easy to realize mechanization and automation, and can produce thin-walled castings with complex shapes. The minimum wall thickness of die-casting zinc alloy is only 0.3mm, the minimum wall thickness of die-casting aluminum alloy is about 0.5mm, and the minimum casting hole diameter is 0.7mm.

-Castings have high dimensional accuracy and small surface roughness values. The dimensional tolerance level of die castings can reach CT3~CT6, and the surface roughness is generally Ra0.8~3.2μm.

-Parts can be embedded in die castings, which not only saves precious materials and machining time, but also replaces the assembly process of components, which can save assembly processes and simplify the manufacturing process.

3.Disadvantage of die casting

-During die casting, the filling speed of liquid metal is high, and it is difficult to completely remove the gas in the cavity. The castings are prone to defects such as pores, cracks, and oxidation debris. Die castings usually cannot be heat treated.

-The die-casting mold has complex structure, long manufacturing cycle and high cost, and is not suitable for small batch casting production.

-The die-casting machine has high cost and large investment, and is limited by the clamping force and the size of the die-casting machine, so it is not suitable for the production of large-scale die-casting parts.

4.Application fields of die casting

Due to the advantages of die casting, it is widely used, mainly used in mass production of non-ferrous alloy castings. In the output of die castings, aluminum alloy die castings account for the largest proportion, accounting for 30% to 50%; followed by zinc alloy die castings; copper alloy die castings account for 1% to 2%. The most widely used die-casting parts are the automobile and tractor manufacturing industries, followed by the instrument manufacturing and electronic instrument industry, and again for the agricultural machinery, national defense industry, computer, medical equipment and other manufacturing industries. The parts produced by die casting method include engine cylinder block, cylinder head, gearbox case, engine cover, instrument and camera shell and bracket, pipe joint, gear, etc.