Heat Deflection Temperature

The Heat Deflection Temperature is the temperature at which an elastomeric material can be deformed under a specific load.  This is an important parameter which is useful in the design and manufacture of plastic components. 

The Heat Distortion Temperature for a material can be determined experimentally.

ASTM D8 defines the Heat Distortion Temperature as the temperature at which a bar of standard dimension experiences a deflection of .25mm when loaded with a flexural load of  455 kPa.  The heating is done at the rate of 2K per minute. 

A material cannot be used for structural applications at a temperature above its Heat Distortion Temperature. 

In Injection moulding, the part which is moulded can be removed from the mould once it is near or below the Heat Distortion Temperature. 

Posted by: Electrotechnik