Linear Thermal Shrinkage or Free Shrink is defined as the irreversible and rapid decrease in linear dimension, in a specified direction, occurring in film exposed to high temperatures.  Shrinkage in this way is related to the material of the film and internal stresses locked into the film during the manufacturing process.   

The IDM Film Free Shrink Tester consists of a small, circular aluminium block, electrically heated and controlled by a digital temperature controller.  Using aluminium foil discs with silicone oil, the test piece is placed into it to accelerated shrinkage at selectable temperatures ranging from Ambient to 250°C. 

The compact and light-weight instrument is manufactured with relevance to internationally recognised ASTM test method, and is a sought test within the flexible packaging and shrink packaging industries.  It is a very easy to use instrument, requiring minimal setup procedures.