Improper venting during moulding process causes a diesel effect which further results in stress crack defects in the casting.
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For proper venting, the pouring time is increased which allow easy escape out of gases from the mould without inducing any defects.
High viscosity of molten metal can help in removing of gases but will cause defects in the casting.
Porous sintered materials can be inserted into the mould cavity to act as a vent.
Vacuum technology for venting process is very economical and widely used in the casting process.
In the injection moulding process, an overflow system is used for the venting process.
For the venting process, the casting yield is generally high with the overflow system in the mould.
In the injection moulding process, venting at the runner side can reduce the air pressure.
Cores generally experience a single force called gravitational force in the mould.
In the mould, the heat experienced by the core is much severe than that of experienced by the mould wall.
The buoyancy force is generated only due to the weight of the core inside the mould.
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