Common defects in aluminium castings include:

  • Porosity: Small holes or voids within the casting caused by trapped gas. Avoidance involves controlling the mold and molten metal temperatures and using proper venting techniques.
  • Cold Shuts: Occur when molten metal cools prematurely before completely filling the mold. This can be mitigated by optimizing gating design and ensuring proper pouring temperatures.
  • Shrinkage: Occurs when the metal solidifies and contracts, leading to voids. Compensating for shrinkage by designing moulds with allowances or adding risers can prevent this.
  • Misruns: When the molten metal solidifies before reaching all parts of the mold. To avoid misruns, casting temperature and mold design should be carefully controlled.
  • Surface Defects: Such as rough surfaces or inclusions, can be avoided by ensuring proper mold finish, material selection, and casting process.

Proper process control, high-quality materials, and skilled workmanship can minimize these issues.