Precautions for the production of small Dalian aluminum die-casting parts: detailed control of temperature control and pressure regulation

Precautions for the production of small Dalian aluminum die-casting parts: detailed control of temperature control and pressure regulation

Small aluminum die castings (such as electronic connectors, precision gears, etc.) are more sensitive to temperature and pressure changes during the production process due to their compact structure and thin wall thickness (often less than 3mm). Even slight deviations may result in defects such as insufficient filling and deformation, and attention to detail is necessary.

The temperature control of Dalian aluminum die-casting parts needs to take into account both the aluminum liquid and the mold dimensions. The temperature of the aluminum liquid needs to be 5-10 ℃ lower than that of large castings (such as ADC12 alloy controlled at 640-660 ℃). If the temperature is too high, it can easily lead to more burrs in the casting, while if it is too low, it will be difficult to fill the small cavity due to insufficient fluidity; At the same time, it is necessary to accurately control the mold temperature. Small casting molds have a small heat capacity and require temperature control through heating rods in different zones to stabilize the surface temperature of the mold cavity at 180-220 ℃, avoiding excessive local temperature differences that can cause stress concentration and cracking in the casting. In addition, an insulation furnace is required during the transfer process of aluminum liquid to reduce temperature loss and ensure that the temperature fluctuation does not exceed ± 5 ℃ when entering the injection chamber.

 

The pressure regulation of Dalian aluminum die-casting parts needs to pay attention to stage and refinement. The pressure during the slow injection stage needs to be reduced to 20-30 MPa to avoid the impact of aluminum liquid on the corners of the mold cavity causing gas entrapment; The rapid injection pressure needs to be adjusted according to the wall thickness of the casting. For thin-walled parts (1-2mm), it needs to be increased to 50-70MPa to ensure that the aluminum liquid quickly fills the mold cavity. For thick walled parts (2-3mm), it should be controlled at 40-50MPa to prevent deformation of the casting due to excessive pressure; The pressure during the holding stage needs to be kept stable, usually 80% of the fast injection pressure, and the holding time should be controlled between 0.5-1.5 seconds. If it is too short, it may cause shrinkage and looseness, and if it is too long, it may lead to mold sticking of the casting. At the same time, it is necessary to regularly calibrate the pressure sensor to ensure that the deviation between the displayed pressure value and the actual value does not exceed ± 2MPa, in order to avoid affecting the quality of the casting due to inaccurate pressure.