Advances in Industrial and Manufacturing Engineering (May 2021)
Bi-polynomial fourth-order weld bead model for improved material utilization and accuracy in wire-arc additive manufacturing: A case of transverse twin-wire welding
Abstract
With the gradual evolution of metal additive manufacturing (AM) as a viable manufacturing option for realizing complex parts, the research focus has shifted from mere geometric realization to a higher material deposition rate without a significant loss of accuracy. This work aims to demonstrate the potential of traverse twin-wire welding to produce asymmetric weld beads, providing an extra control factor in the weld bead shape and component accuracy while retaining high deposition rates. A new weld bead model - bi-polynomial fourth-order - is developed and linked to the process conditions. The higher-order model is more responsive to the weld bead shape variation and is more accurate than the traditional models. Compared to conventional single polynomial models, which are limited to the symmetrical cross-sectional weld bead, the bi-polynomial model can also simulate the asymmetrical weld bead. The process model of the weld bead and the offset are integrated with the product features to assess the time for fabrication (number of passes) and post-machining material wastage. The usefulness of the integration is demonstrated with the manufacture of a candidate multi-pass multi-layer component. It is envisaged that the investigation will facilitate large-scale wire-arc AM with the use of transverse twin-wire welding.