USE OF A CHARGED COUPLED DEVICE (CCD) CAMERA FOR EVANESCENT-WAVE OPTICAL-FIBER CURE MONITORING OF LIQUID COMPOSITE MOLDING RESINS

An optical fiber evanescent wave fluorescence cure sensor described in a previous paper (1) has been interfaced with a fast detector and com puter software to provide real-time monitoring of fast-reacting system s. Advantages to the new system include a reduction in data acquisitio n time (to 200 ms from 3 min), improved time resolution (to 5 sec from 10 min), and improved signal quality. Isothermal cure monitoring meas urements were conducted in both distal and evanescent wave sampling mo des for an epoxy-amine system. Following a second order background cor rection, the results for the two sampling modes were identical. Thus t he evanescent wave measurement was unable to detect differences betwee n the chemistry in the bulk and at the fiber-resin interface (if there were any differences to observe). The sensor system was also demonstr ated for a fast curing (<3 min gel time) polyurethane-isocyanurate sys tem designed for high volume (short cycle time) automotive application s. The system is currently being modified for implementation in a ''re al world'' manufacturing environment.