Multi-sensor in process monitoring for WAAM: Detection of process instability in electrical signals

Abstract. Wire Arc Additive Manufacturing (WAAM) is a promising process for producing medium to large scale metallic parts at a low cost and with a high deposition rate. However, the multitude of process parameters and physical phenomena involved makes it complex and hard to master. Therefore, monitoring the process becomes crucial for unraveling complexities and attaining a more profound comprehension of the intricacies inherent in WAAM, hence ensuring process stability. In order to produce a defect-free part, while keeping a stable process, the operating parameters must be carefully selected. Nonetheless, one of the significant hurdles in WAAM is the variability of the deposited layers height. The accumulation of these geometrical inaccuracies induces instabilities in the process which results into the appearing of defects on the deposited part. The aim of this study is to investigate the correlations between process instabilities and electrical signals obtained by a deposition monitoring system. A monitoring criterion is then extracted from experimental data. Correlation with instabilities will be confirmed using a thermal camera.