A profile transformation based recursive multi-bead overlapping model for robotic wire and arc additive manufacturing (WAAM)

Abstract

Robotic Wire and Arc Additive Manufacturing (WAAM) is an ideal process for manufacturing large-scale or large-format parts efficiently and economically, as compared with other AM methods, and therefore finds extensive applications in diverse fields including aerospace, automotive and mould. Accurate prediction of WAAM part dimension is fundamentally dependent on the modeling accuracy of single-bead profile and its subsequent overlapping ones. This paper proposes a new recursive model, based on coordinate transformation, to predict single-layer multi-bead overlapping profile. Firstly, commonly used single-bead profile functions are reviewed, followed by detailed description of conventional and proposed recursive profile model. The properties of developed recursive model are then investigated for understanding the effects of overlapping ratio and single-bead aspect ratio. The influence of function type is also analysed from the surface quality divergence of single-layer multi-bead overlapping profile. Finally, multi-bead overlapping experimental tests are carried out to validate the feasibility of presented recursive profile model. The results show that the modified recursive model is more accurate than the conventional one for its better accountability of valley area. It is also indicated that parabola and arc function are more suitable for the robotic WAAM process. The research outcome is beneficial to improving the forming accuracy of WAAM parts, and also provides a new method for predicting geometry of other additive manufactured products.