Real-time detection of defects in WAAM specimen under poor surface quality using ACFM technology

Wire and Arc Additive Manufacturing (WAAM) is well-suited for the economical and efficient rapid fabrication of large-scale components. The WAAM process involves substantial energy input and intricate energy exchanges, which can result in the formation of cracks, pores, and other defects. During defect inspection, the poor surface quality of the cladding layer can interfere with detection results, leading to potential missed detections or misjudgements of defects in real time. In this study, a real-time detection method and instrument were developed for identifying defects in WAAM specimens using the Alternating Current Field Measurement (ACFM) technique. Firstly, based on the theory of ACFM, a theoretical model of cladding layer defects was established. Secondly, a high resolution array ACFM detection probe and an instrument were developed. Finally, a real-time defect imaging discrimination algorithm was programmed using an FPGA platform. The system was tested with cladding layer defects of various sizes. The results indicated that the system can achieve real-time imaging and accurate identification of defects in rough surface workpieces, offering advantages such as fast detection speed, high efficiency, and accurate results. The research findings were of great significance for improving quality control and defect detection technology in the WAAM field.