Impact of process parameters on forming quality and deposition efficiency of unsupported rods in wire arc additive manufacturing

Unsupported rods as the basic element of lattice structure, improving their forming quality and deposition efficiency still poses a challenge in wire arc additive manufacture (WAAM) due to the significant thermal accumulation and high heat input. Comprehending the impact of process parameters is paramount in optimizing the WAAM process, enhancing the quality of manufactured parts, and maximizing deposition efficiency. This paper investigated the influence of arc parameters on the deposition process of unsupported inclined rods fabricated by WAAM and revealed the mechanism by which process parameters affect the forming quality. The results found that high peak current and low duty cycle in pulse current resulted in rapid solidification and favorable morphology. In contrast, using lower or higher arc frequencies led to poor forming quality. While increasing voltage can enhance the distance between the tungsten electrode and the molten pool, it may consequently cause instability in the arc and affect the forming process. The deposition efficiency has been greatly improved (from 15 mm/min to 48 mm/min) by appropriately increasing torch travel speed and wire feeding speed, which can also reduce the arc heat input, refine grains, and enhance mechanical properties. In summary, this study contributes to the understanding of process parameters in wire arc additive manufacturing, enabling the production of high-quality lattice structures and maximizing deposition efficiency.