2.4 casting and moulding

• Sand casting


  A shaping process where a mould made from sand is filled with molten metal
• Sand casting


  1. Mould made from sand

  2. Filled with molten metal

  3. Mould is destroyed after use
• Pressure die casting


  A shaping process where molten metal is forced into a reusable metal mould
• Pressure die casting


  1. Molten metal is forced into a reusable metal mould

  2. Pressure forces the liquid metal into the cavity

  3. Once solidified, the die is taken apart and the cast part removed

  4. Castings are typically more accurate, with more detailed features and better surface finish
• Injection moulding


  A shaping process for polymers, where the polymer is forced into a reusable metal mould
• Sand casting and pressure die casting

  • Used to make 3D metal parts
  • Sand casting uses a mould made from sand, which is destroyed after use
  • Pressure die casting uses a reusable mould made from metal
  • Due to the cost of the equipment, pressure die casting is typically only used when a large quantity of parts is to be made
• Injection moulding


  • Similar to pressure die casting, but for parts made from polymer