In-line and off-line NDT defect monitoring for thermoplastic automated tape layup

Automated tape layup (ATL), is susceptible to a variety of manufacturing defects that affect productivity and mechanical performance of the final part. To increase process efficiency an inline monitoring tool is developed, which detects defects during manufacturing in a ply-by-ply manner. The presented work details the capability analysis of inline non-destructive testing (NDT) by means of thermography compared to industry approved NDT methods, namely, active infrared thermography and ultrasonic testing, which are performed subsequently. Two sets of samples were made, with foreign object and debris (FOD) and without any artificial defects. These in-situ consolidated samples were then checked for FOD and bond inhomogeneity via all three NDT methods. Quantitative and qualitative analysis of research finding was performed. Inline thermography results conform to established industry standards in recognizing FOD defects. These defects can be localized and rectified immediately, increasing process reliability. Inline thermography can be used effectively for inline process control.