Casting and Moulding

Casting and Moulding

1. Sand Casting: Mould is made from sand mixed with a binder material.

   • 70% of metal casting can be accounted for by this process
     • Sand Casting allows most metals to be cast depending on the type of sand used for the moulds

2. Plastic Moulding: Suitable for very small parts. Only low melting temperature non ferrous meterials, such as aluminium, copper, magnesium and zinc can be used

3. Shell Mould Casting: Cavity is formed by a hardened shell of sand and resin instead of a flask filled with sand. Sand is mixed with a resin and heated by the pattern and hardened in to a shell around the pattern

4. Shell Casting: This is easily automated and more precise than sand casting. Common casting metals are Iron, Aluminium, Magnesium and Copper Alloys. The process is ideal for complex items that are small to medium sized.

5. Investment Casting: Offers unlimited freedom in both complexity of shaped and types of materials to cast. When its heated to harden into a shell the wax material melts. The wax can be reused many times.

6. Permanent Casting: Reusable moulds. Common casting metals are aluminium, magnesium, and copper based alloys. Iron and Steel can also be cast if using graphite moulds

7. Die Casting: Forcing molten metal under high pressure into a mould cavity, most die castings are made from non ferrous metals.

   • Centrifugal Casting: The process where molten metal is poured in the mould and allowed to solidify while the mould is rotating. Jewelry are often cast by this method.
     • Injection Moulding: Most widely used process for high volume production of relatively complex thermoplastic parts.
       • Blow Moulding: Used to manufacture bottles and containers with very thin walls. Materials: Thermoplastic polethlyene, PVC, polyproptlene.
         • Hot compression moulding: Technique used for a variety of product manufacturing, including the production of complex parts, large and small. the method is favoured as a lower cost alternative injection moulding.It offers an additional cost advantage in that is wastes relatively small amounts of moulding material.