A film or sheet is formed by heating polymer to a molten state. The process is most often extruded or calendared. In the process, the molten film is pulled under tension, thus caused a stretching in machine direction. Then the film is cooled to form into a given thickness, width etc. Some undesirable stressed are locked in. When a plastic film or sheet is reheated, it can change in linear dimension. This is typically referred to as shrinkage. Shrinkage is also important because it can tell how the plastic was made. It can be used for quality control or process control.

STANDARDS

1.P.I.D. temperature control
2.High precision timer
3.Alarming function
4.Stable heating of fluid medium
5.Standard square metal clamp and free shrink holder

STANDARDS

ASTM D2732, ISO 11501 , GB T13519