Online thermography inspection for automated tape layup

Online process monitoring and quality assurance are highly favorable for composite manufacturing processes like automated tape layup (ATL), where the productivity is largely constrained by downtime consisting of quality inspection and error mitigation. The presented work details the use of thermography as an inspection tool for such a process, using thermoplastic based tape material. A new online monitoring system is developed containing Infrared camera integrated on a purpose build ATL test rig. Surface thermal history for the layup course over time is recorded, which is then extracted along the width of the tape. The end result is a single image containing sequence of images, detailing the temperature data over the length of a single tape. Temperature gradient throughout the layup is then used to recognize foreign bodies and defects. Variation in adhesion effects of ply to the tool, ply and ply and ply and foreign bodies can be detected and areas of weak bonding can be recognized.