Process and apparatus for controlling curing and thermoforming of resins and composites

Composite materials (17) of reinforcing fibers are impregnated with polymeric matrices which may contain fillers and are then cured or thermoformed. As curing or thermoforming proceeds, dielectric detection is employed to closely monitor critical process events such as the release of volatiles, chemical reactions such as cross linking, melting and solidification. Curves are generated by plotting factors of the dielectric loss of the polymer matrix against time during the process; these plots have a distinctive shape or signature characteristic of the particular polymer matrix being processed. These distinctive features or signatures have been found to correlate with critical process events and are stored in a computer. During a cure cycle, the computer actuates the controls of the heating system so that the appropriate process actions or modifications will occur at the optimum time. The process controls are thereby adapted to produce an optimized high quality product.