Method And Apparatus For Dielectric Sensing In A Thermoplastic Winding Process

Abstract

Disclosed are a method and apparatus for real time process monitoring of thermoplastic filament winding. During processing, the thermoplastic filament winding is wound around an electrically conductive mandrel. An electrically conductive roller, juxtaposed and movable radially with respect to the mandrel, is provided for compression of the portion of the thermoplastic filament disposed on the mandrel. Accordingly, a dielectric capacitor is formed between the mandrel and the roller with the portion of the thermoplastic disposed between the mandrel and roller acting as the dielectric of the capacitor. An input voltage is applied to the dielectric capacitor, and the permittivity and loss factor of the capacitor are determined by monitoring the input voltage and output current to thereby determine the degree to which the thermoplastic has consolidated.