Why does porosity occur in die casting and how can it be avoided?

Porosity is formed when gas or air is not completely expelled from the molten metal. Common causes include poor exhaust design, excessive metal injection rate, and uneven cooling. Measures to avoid porosity are:

• Improved exhaust design: Ensure that the mold is designed with adequate air vents.
• Control of injection rate: Avoid excessive injection pressures and velocities that result in trapped gas.
• Optimization of casting temperature: Ensure that the molten metal is at the right temperature and avoid overcooling or overheating.