A review on wire-arc additive manufacturing: typical defects, detection approaches, and multisensor data fusion-based model

Wire-arc additive manufacturing (WAAM) technology integrates the characteristics of additive manufacturing and traditional welding technology. It has been found to be capable of forming large-scale metal components with low cost and higher deposition rates. However, it also has potential issues in morphological accuracy, microstructure, and properties due to the arc-based metallurgy mechanisms with complex thermal cycles. This article intends to give a detailed overview of the quality diagnosis and control of the WAAM process, including the formation mechanisms of typical defects, detection approaches, and detection challenges that remain in the WAAM industrial environments. Subsequently, a multisensor data fusion-based closed-loop quality control model is proposed. This model could provide a feasible solution to ensure the quality and deposition efficiency of WAAM parts in complex manufacturing conditions. Based on this model, a novel process named hybrid deposition and micro-rolling (HDMR) is introduced as the green transformation of traditional manufacturing approaches with higher energy efficiency and better quality.