What is the role of compressed air during the aluminum alloy liquid die casting process?

In the aluminum alloy hydraulic casting process, compressed air plays multiple key roles, and its role can be summarized into the following four core links:

1. Power source for liquid metal transportation
In the low-pressure casting process, dry compressed air is injected into a closed crucible, creating a pressure difference on the surface of the liquid metal. This pressure forces the molten metal to rise steadily along the riser pipe in a bottom-injection manner to fill the casting cavity. The entire process pressure is usually controlled at 0.01-0.05MPa (or 20-60KPa) to ensure smooth flow of molten metal and avoid splashing and gas entrainment, thereby significantly improving the internal quality of the casting and reducing shrinkage porosity defects.

2. Key parameters for precision forming control
After the molten metal fills the mold cavity, crystallization and solidification of the molten metal under pressure can be achieved by adjusting the pressure of the compressed air. This pressure control technology can optimize the tissue density and surface finish of castings, especially for large thin-walled parts or complex structural parts, which can ensure clear contours and meet mechanical properties.

3. Efficient executors of auxiliary processes

• Mold pretreatment: High-pressure air flow is used to clean the mold surface, remove residues, and ensure the cleanliness of the mold cavity.
• cooling acceleration: Compressed air can accelerate the heat dissipation of castings and shorten the production cycle.
• Demoulding assistance: Air pressure helps separate the casting from the mold to reduce mechanical stress and avoid deformation of the casting.
• Automated post-processing: Drive pneumatic tools for cutting, polishing and other operations to improve production efficiency.

4. Quality assurance of process stability
The water-lubricated screw air compressor can provide stable and clean compressed air with low pressure dew point and can meet the pneumatic component requirements of precision CNC machine tools. This ensures the movement accuracy of pneumatic actuators (such as cylinders), reduces the casting defect rate, and ensures the stability of the casting process and the quality of the casting.

In summary, compressed air is not only the core driving force for liquid metal transportation in aluminum alloy hydraulic casting, but also comprehensively improves casting efficiency and casting quality through multiple functions such as precision control, auxiliary processes and quality assurance. It can be called the “invisible push hand” in the process chain.