The Coefficient of Linear Thermal Expansion Tester has been designed and manufactured by IDM Instruments to determine the coefficient of linear thermal expansion for plastic materials. At the test temperatures and under the stresses imposed, the plastic materials shall have a negligible creep or elastic strain rate or both, insofar as these properties would significantly affect the accuracy of the measurements.
The thermal expansion of a plastic is composed of a reversible component on which are superimposed changes in length due to changes in moisture content, curing, loss of plasticiser or solvents, release of stresses, phase changes and other factors. Using this test to determine the coefficient of linear thermal expansion, these factors shall be excluded as much as possible.
The Coefficient of Linear Thermal Expansion Tester is manufactured using a Dilatometer mounted from a vertical post. A dial gauge is used to measure the changes in length.