Melt flow tests are a simple method of characterizing the flow properties of a plastic melted mass. This test method is widely used, especially in quality assurance and goods inwards testing. The demands placed on the melt flow index tester / extrusion plastometer vary according to which processing stage in the plastics industry is involved.
Many plastics applications are placing increasing demands on heat resistance. An important value with regard to the temperature resistance of plastics is the heat deflection temperature. This can be divided into Vicat softening temperature and HDT (heat deflection temperature). In both methods an oil-bath is heated at a defined rate and the temperature is recorded at a deflection or indentation depth specified by the standard.