Permanent mould castings

A metal is used as mould in place of sand. Basically cast iron or Meehanite (a dense cast iron) are utilized for making moulds and cores are made of metal or sand. Cavity surfaces can be covered with a thin layer of heat proof material of clay or sodium silicate.

The moulds need to be preheated up to 200 degree Celsius prior to metal being poured in cavity. The cavity pattern of those moulds does not follow similar rules of shrinkages as in sand casting moulds. The reason is, metal moulds heat up and expand during the pour therefore, the cavity does not expand as in sand castings. Though care must be taken to keep correct thermal balance; by having outside water cooling.

Permanent mould castings are not as flexible as sand castings in using various designs that are cost effective. While producing 1000 or more parts the cost per piece is less. But breaking even is subject to complexity of part. More complex parts are suited to permanent moulds.

• sand casting
• 1. Grey Iron Casting
  2. Aluminum gravity casting
  3. Green Sand Casting
  4. Sand Castings
  5. Aluminum Sand Casting
  6. Ductile Iron Casting
  7. Brass Sand Casting