NDT:
As well as inhouse x-ray and dye penetrant NDT facilities
we use third
party mechanical and magnetic particle testing
to verify product conformity.
HEAT
TREATMENT:
A wide range of ovens allows us to heat treat castings
and other components.
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GENERAL
CASTING TOLERANCES:
Standard tolerances, casting draft angles and shrinkage
allowances are detailed below:
INVESTMENT
STANDARD TOLERANCES:
Castings should be within linear tolerances of ±0.15
upto 150mm and ±0.05 upto 25mm thereafter.
SAND
CASTING STANDARD TOLERANCES:
Castings should be within linear tolerances of ±1.0 upto 150mm and ±0.20
upto 25mm thereafter.
PLEASE
NOTE: The above tolerances are for guidance
purposes only and may vary where contraction is hindered
by design of the component / mould.
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CASTING
DRAFT ANGLES:
The draft or amount of taper given to the pattern
to facilitate withdrawing from the mould depends
somewhat on the size and shape of the pattern.
A general guide would be 1 to 2 degrees of taper
per side:
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SHRINKAGE
ALLOWANCE: Shrinkage allowances are approximate
values only, since the exact allowance depends
upon the size and shape of the casting and resistance
of the mould. It is, therefore, possible that more
than one shrinkage allowance will be required for
different parts of the same pattern / casting.
A general guide for aluminium alloy castings would
be 1.3%.
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