Quality inspection for thermoplastic Automated Tape Layup is largely constrained to post manufacturing, manual visual inspection. This means risking undetected flaws, higher repair costs, possible rejection of the part and material and productivity loss. Online monitoring capable of detecting, localizing and quantifying defects at both material and laminate level is required.

The present research work focuses on an all-inclusive holistic approach towards quality assurance. Defects are detected at each step, starting from raw material, processing and post processing. Multiple sensors are integrated in the test-rig, which record inline data with online detection capabilities. Defects in the tape properties such as splice, slits, and dimensions are recorded before layup, using light section sensor placed before the consolidation roll. Processing parameters, nip-point temperature and consolidation force, are recorded during layup, using a pyrometer and a 6-axis force sensor respectively. This way, the accuracy and precision of the test-rig is kept in check. Flaws in resulting laminate properties, such as surface temperature anomalies, foreign bodies, placement defects and resulting dimensions are inspected using a IR camera and another light section sensor placed after the consolidation roll. In this way, defects can be recognized at each stage of the process and based on the criticality, can be rectified accordingly.

To have better control of the defects and overall process, force control is implemented. Consolidation force has the least effect on the bond strength and is relatively easier to characterize compared to heat input. It also has a direct impact on the dimensional changes of the tape and, therefore positioning and tape defects, like overlaps, gaps, slits. Controlling the force thus helps in limiting the defects.