Selection of Process Parameters for Near-Net Shape Deposition in Wire Arc Additive Manufacturing by Genetic Algorithm

In wire arc additive manufacturing (WAAM), deposition of multiple beads in multiple layers is required for fabricating any component. This article presents ways to optimize the selection of parameters for near-net shape deposition to minimize void and excess material in WAAM by GA. Initially single-bead geometry model was developed utilizing response surface methodology and experiments were conducted utilizing Box-Behenken design of experiments for deposition of 304L stainless steel in WAAM. Bead geometry parameters, i.e., bead width, bead height and bead cross-sectional area, etc., were expressed in terms of the process parameters like voltage, wire feed rate, torch speed and gas flow rate. Optimal processing conditions and deposition planning were determined utilizing a GA to minimize void and maximize material yield. The proposed approach was validated through deposition of three shapes, i.e., slice, wall and block. The three shapes fabricated with optimal parameters were found to have minimum void and maximum material yield. It has been revealed that optimal bead sizes and degree of overlapping are different for fabricating different geometries. Mechanical testing and metallurgical characterization of the deposited materials exhibited comparable properties of the deposited material to that of the base material. Moreover, double wire feed deposition was seen to deliver higher deposition rate and superior mechanical properties of the deposited material compared to the single wire feed deposition.