ISO 17744 Determination of specific volume as a function of temperature and pressure (pvT diagram)

In the process of Injection Moulding, significant failures can occur even if mould filling has been successfully executed. This is because contraction of the plastic product upon cooling can introduce residual stresses or even failure or warping of the part. ISO 17744 helps the mould designer to mitigate against this risk and minimize failure opportunities by predicting the volume shrinkage of the melt between different conditions. The test is performed by enclosing the specimen in a high-pressure device with temperature and volume control, for example a capillary rheometer with suitable fixtures to plug the die exit. Then a variety of conditions can be applied, and a map of pressure, volume and temperature (pvT diagram) can be generated. Typically, one of these variables is held constant throughout testing.

This test can be performed using the our capillary rheometers. By simply re-configuring the system with some basic accessories, the rheometer becomes an invaluable tool for building a pvT diagram. And then, just as simply, the rheometer can be re-configured for standard testing.