Analysis of process parameters, deposition strategies and build orientations in wire-arc additive manufacturing (WAAM)

Additive manufacturing (AM) has transitioned from prototyping to commercialization in many industrial sectors. In addition, direct energy deposition (DED) processes are enabling the AM for large-scale depositions. One such DED process is wire-arc additive manufacturing (WAAM), popular for its high deposition rates. The influence of process parameters and deposition strategies play a vital role in the WAAM process. Therefore, in the first part of this study, a response surface methodology (RSM) was employed based on a central composite design (CCD) for bead-on-plate analysis to understand the effects of process parameters on bead morphologies and material hardness. Similarly, for the second part of the study, different deposition strategies were employed for test wall depositions to analyse their effects on built structures. Particularly, the effects of layer-stacking on 10-layer and 20-layer walls were analysed in detail. Finally, employing an optimised deposition strategy, cubic samples were deposited with various deposition parameters based on a 2 K factorial design. Hardness, microstructural and SEM analysis were performed for in-depth analysis of the samples. Results revealed a strong relationship between process parameters (current and travel speed) versus bead characteristics and material hardness. The deposition strategies significantly influenced the built structure and wall formation. Similarly, layer-stacking played a critical role for mechanical properties of deposited samples. Cubic structures demonstrated small anisotropy for microstructural results based on various parameter settings. Similarly, small discrepancies were observed in the hardness results.