The apparatus is used to test the heat distortion temperature of plastic materials. It is also used to test short term heat resistance of plastic materials. This is achieved by measuring the temperature at which the sample to be tested deflects by a given distance under an applied pressure.

Test Method

• The test involves inserting moulded plastic test pieces into a closed oil bath.
• Then the oil is heated and the heat is controlled to maintain a uniform rate of rise of heat.
• The test sample is supported at both ends and a uniform pressure is applied between the supports.
• With the heating of the oil in the oil bath, the moulded plastic test piece is also heated up.
• As a result the sample becomes more flexible and applied pressure causes it to bend.
• The temperature at which the plastic test sample is distorted at a pre-defined distance is known as the heat distortion temperature.

Applications

The apparatus finds wide application in many different fields. Some of its application areas are:

• Plastic Industry
• Chemical Industry
• Research & Development