Real-time in-situ process monitoring method based on the self-conductivity of carbon fiber prepreg for automated fiber placement (AFP)

Abstract

Real-time online monitoring is of great significance for the manufacturing of carbon fiber reinforced composites, contributing to improving and ensuring the quality of the final manufactured part. An in-situ real-time process monitoring method based on the conductivity of continuous carbon fiber reinforced thermoplastic matrix prepreg was proposed for automated fiber placement (AFP). The detection capability of several different defects was investigated, including foreign object debris, tape breakage, weak edge bonding, gaps/overlaps, and even debonding. In addition, the influence of placement speed and laser power on the detection capacity was also discussed. The number, position, length, and width of various interlayer defects were detected through the resistance change between the current placement layer and the laid layers. Furthermore, accurate detection of defects in different layers was also achieved, indicating the detection capability of existing defects. This method of timely defect detection during the manufacturing process allows for an early manual intervention to improve the quality of manufactured structures and the intelligence of AFP technology.