Process stability and forming accuracy on wire arc additive manufactured Al–Zn–Mg–Cu alloy with different electrode positive/electrode negative ratios of CMT advance process

Abstract

The influence of electrode positive/electrode negative (EP/EN) ratio on cold metal transfer advance-based wire arc additive manufacturing (WAAM) process for Al–Zn–Mg–Cu alloy was studied in this paper. The process stability was investigated via analysing electrical waveforms and arc/metal transfer images concurrently. A high EP/EN ratio (≥ 13:7) was beneficial to decrease abnormal long wait phase duration of current and spatter of droplet, which improved the stability of WAAM process. The forming accuracies of the samples increased first and then decreased with the increase of EP/EN ratio due to the incompatibility of the heat input and molten pool flow. The average width and effective width coefficient showed a positive correlation with EP/EN ratio.