Effect of arc dynamic behavior on deposition quality of additive manufactured aluminum alloys

[Display omitted] •The spectral intensity of arc plasma during WAAM was related to the size and straightness of arc.•The spectra and dynamic behavior of arc fluctuated with the change of forming size.•The arc behavior varied regularly with the electrode polarity and deposition location. With the rapid development of arc additive manufacturing, higher requirements were put forward for the in-situ detection of the deposition process. By acquiring arc spectral and image signals in real time, this paper explored the forming mechanism of additive manufactured Al alloy parts and the relationship between deposition sizes and sensor signals. Based on the calculated physical properties of arc plasma in the whole manufacturing process, the influence mechanism of the heat input on arc plasma dynamic behavior was analyzed. Moreover, the effects of deposition locations and the electrode polarity on arc behavior were revealed based on arc images obtained by the high-speed camera. The features of spectral and image signals corresponding to typical defects were determined. The relationship between the deposition quality and sensor signals was established, which was of great significance for the on-line detection and control of arc additive manufacturing.