Influence of wire-arc additive manufacturing path planning strategy on the residual stress status in one single buildup layer

In recent years, the significant residual stress in the wire-arc additively manufactured components has been continuously one of the most concerning issues for the further development of the wire-arc additive manufacturing (WAAM) technology. Although many pre/post processing methods have been proved capable of modifying the residual stress, few works have been conducted to reduce the residual stress using appropriate path planning. In the present research, a WAAM path planning strategy is developed combining both zigzag and contour-offset methods, which aims to obtain a single WAAM deposition buildup layer with both optimal outline accuracy and residual stress status. The path planning and residual stress measurement processes have been carefully designed to acquire reasonable results. According to the residual stress results measured using X-ray diffraction method, the arc deposits finished with more contour-offset paths contain smaller tensile residual stresses, which is due to the hooping function of the outer contour deposit path to the inner deposit. Therefore, it can be concluded that the offsetting of the external contours before zigzag filling the internal dimensions is beneficial to both the residual stress distribution and shape outline accuracy of the WAAM buildup layer.