National Physical Laboratory

Pressure Volume Temperature (PVT) Measurements

Pressure Volume Temperature (PVT) MeasurementsImage courtesy of iStockphoto 

Achieving tight tolerances and minimising cycle times are important objectives for the polymer processing industry with obvious commercial benefits. The ability to predict the shrinkage and warpage of plastic components, with confidence, will enable injection moulders to take on premium work, requiring tight tolerances, with increased confidence and reduced scrap rates. In order to make accurate predictions, good data are required on the behaviour of the polymer under the conditions experienced during moulding. This is particularly important to reduce the time to market of new products by getting the mould design right first time.

The relationship between pressure, volume and temperature (PVT) of the polymer needs to be measured at industrial processing conditions. As injection moulding is a rapid, high pressure process, PVT data are required by the commercial software companies at high cooling rates and under high pressure on thin samples, which until recently were unavailable.

However, NPL has now made this possible by developing state-of-the-art PVT equipment which can measure PVT behaviour at high cooling rates (up to 250 °C/min) and at high pressures (up to 250 MPa).


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Last Updated: 25 Mar 2010
Created: 8 Aug 2007


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