Instruction manual

OPERATING_MANUAL_MC20V.DOC 18.03.11 KS Seite 39
Incomplete castings
Cause Remedy
Metal or flask too cold. Increase casting temperatures. If the
metal or mould is too cold, the metal will
freeze before completely filling the
mould.
Improperly sprued. The sprue system should be designed to
allow the metal to enter easily and
without restriction.
Incomplete burn out. Increase the burn out time at 730ºC. If
the flask is not properly burnt out it will
be impermeable and not allow gases to
escape when the metal enters the mould.
Shrinkage porosity
Cause Remedy
Incorrect sprue Sprues should be attached to the
heaviest piece of the casting. There
should be sufficient sprues to ensure the
casting is adequately fed.
Flask temperature too low and sprue is
incorrect.
The flask temperature should be just hot
enough to achieve complete fill,
according to the mass of casting