1.
Mould Cavity:
While making a mould cavity with desired shape and size, one must keep
in mind the shrinkage factor of the solidifying metal. The cavity must
contain with in itself all complexity of shapes of the desired finished
component.

Selecting
the right mould material is also very important as it must be capable of
reproducing the desired detail. The mould material should not be
affected significantly by the molten metal that it must contain. In case
of expendable moulds, a new mould must be prepared for each casting.
Whereas, reusable or permanent moulds can be used more than once. The
latter type are made from such materials that can withstand repeated
castings. The permanent moulds are very costly as these are made of
metal or graphite and are used for large production runs. For smaller
quantities production, the expendable moulds are generally preferred,
simply because of their economical aspect.
2.
Melting Process
The objectives of melting process are:
- Providing molten material at the proper temperature.
- Providing molten material in the desired quantity
- Acceptable quality
- Reasonable cost.
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3. Pouring Techniques
It is a technique by which the moulds are filled in with molten metal.
There must be provisions for air or gases inside the mould to come out
when the molten metal is poured in. When the hot metal enters the mould
cavity, it may generate various gases due to chemical reactions. The
mould design should allow these gases to escape, so that the molten
metal can spread and fill the mould cavity completely. It helps in
producing defect free, fully dense and quality casting components.

4. Solidification Process
Better design and control at this stage helps in getting quality
output. The mould design should be such that it put less restraint to
the shrinkage that occurs during the cooling of metals. It helps in
preventing any kind of crack on the casting when it is still hot and its
strength is low. Moreover, the designers should also be careful about
the fact that porosity or voids may occur during solidification and
solidification shrinkage. A quality casting product should be free from
these defects.

5. Mould Removal
After proper solidification, the casting should be removed from the
mould. Generally, expendable moulds are broken apart and destroyed after
each casting is produced without any difficulty. But, using re-usable
moulds may cause major challenges from designers' point of view on the
removal of casting from permanent moulds.

6. Cleaning, Finishing and Inspection
Various cleaning, finishing, and inspection operations are performed
after the casting is removed from the mould. Extraneous material that is
attached where the metal entered the cavity, excesses at mould parting
lines, and mould material that is attached to the casting surface must
all be removed.
