Vacuum Casting Process.

• good welding characteristics
• high mechanical strength
• low production scatter

To satisfy them, a high structural quality is required.

Vacuum casting creates good conditions for decisively reducing gas porosity, since air is evacuated from the die cavity. Depending on the alloy used, the required values may be achieved in vacuum casting even without additional heat treatment. But if such treatment is necessary, it will produce surface flaws in the presence of even minor gas porosity, which cannot be tolerated on the end product.

Casting process requirements
Following are the requirements for an optimal vacuum casting process:

• The vacuum equipment must offer high performance, and the die and shot assembly must be tightly sealed to ensure high process reliability.
• It must be possible to control the velocity and pressure profiles with high precision and high reproducibility and in real time – which can be taken for granted with Buhler Evolution and Carat machines.
• Additional influencing factors such as molten metal feed, die temperate control, plunger lubrication, and die spraying are also optimized to an extent crucial to quality.

Optimized vacuum casting process
The casting process assisted by high vacuum will satisfy the above requirements with a high degree of certainty. Each individual step is optimized, especially in order to further reduce the gas porosity compared with previous vacuum applications.