Online preventive non-destructive evaluation for automated fibre placement

Abstract

The strict quality requirements for aerospace composite structures give rise to costly quality control procedures. In automated fibre placement (AFP) these procedures rely heavily on manual inspection leading to long machine downtime periods and a slower production process overall. A preventive non-destructive evaluation technique of the composite laminate quality based on an online geometric analysis of the fibre using a laser profile sensor has been developed. This sensor has been mounted on a KUKA KR210 R2700 Extra 10-axis robot and software integration was performed using Robot Operating System (ROS). The robot is equipped with interchangeable end-effectors including an automated fibre placement end-effector, developed at TU Delft. The robot mounted laser profile sensor, in combination with robot positional data, was used to create a 3D model of the fibre. This model can be used in two ways. In real-time it can be used to perform an online assessment of the laminate quality including layup geometry, positioning with respect to a reference location, and detection of in-plane buckling defects. Furthermore the full geometric model obtained can be used to validate mathematical or numerical simulations of the fibre placement process and investigate the effects of process variables on the quality of laminate placement and defect creation. In an industrial process this evaluation method can provide full traceability of the part-product quality. The data can both be used during the qualification of a newly designed laminate, but also for quality assurance during series production.