- Sand Selection: Silica sand with high quality is largely preferred as raw material. The grains in it are in a desirable distribution between 50 - 140 mesh in a way that it can be satisfactory packable as also fluid in case of moulding.
- Resin Coating: Thermosetting resin, i. e., phenolic resin is used in coating the sand. The heat resistance, bonding strength, as also as character of curing, are select with care in a suitable resin. The application amount is usually 1 - 3% in terms of weight in relation to the sand, varying with a requirement in a casting.
- Mixing: The resin is mixed with the sand in a high-speed mixer. A catalyst can be added in mixing in order to produce initiation of a curing reaction in the resin. The mixing is timed with great care in order to achieve a homogenous coating on grains of sand.
- Curing: Pre-coated sand is cured at appropriate heat after mixing, which is generally 150 - 250 degree . The stiffening is achieved in the resin coating that makes the sand have its traditional shape - holding quality.
- Pattern making:
- Mold making: Pre-coated resinsand is packed into pattern in boxes. The sand is pressed tightly in order to have a good density as well as eliminate gaps. A series of moulds can be stacked in order to produce a complete mould assembly in case of complex automotive castings.
- Melting:
- Pouring: The metal is cast into pre-prepared moulds. The rate of pouring as well as pouring temperature are essential not to have defects in terms of porosity, shrinkage, as well as cold shuts.
Post - casting Processing
- Shakeout:
- Finishing:
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