In situ measurement of vacuum consolidation of commingled thermoplastic composites using a non-contact displacement sensor

A vacuum consolidation process has been investigated for use with commingled thermoplastic composites. In particular, the vacuum consolidation behavior of commingled polypropylene/glass and commingled nylon/carbon precursors were studied. Laminates were consolidated in a convection oven under vacuum pressure and the thickness change of the laminates was measured by the use of a novel in situ non-contact eddy current displacement sensing technique. An empirical consolidation model was then fit to the measured experimental results to be used to predict future process cycles. The overall quality of the resulting laminates was assessed using cross-sectional analysis and mechanical strength and stiffness testing. Dynamic mechanical analysis and differential scanning calorimetry were also used to measure the physical properties of laminates produced using differing consolidation cycles to further assess the quality of the resulting laminates. The use of a non-contact in situ consolidation measurement technique was shown to be a useful tool for assessing the consolidation behavior of commingled thermoplastic laminates.