A prediction model of layer geometrical size in wire and arc additive manufacture using response surface methodology

Wire and arc additive manufacture has received much concern for its unique advantages in fabrication of large size near net shape components. But the flexibility nature of free arc and time-varying environmental conditions synergistically make shaping path complicated and mutable. In this paper, central composite rotatable experimental design was applied to clarify the mutual relation between input variables (peak current, wire feed speed, and travel speed) and their responses (bead height and width). Moreover, a predicting model was developed, and the validity of the model has been checked by analysis of variance (ANOVA) technique. By using the developed mathematical model, the bead height and width of a single layer are predicted with 95 % confidence level according to the pre-set process parameters. Vice versa, control strategies are proposed to keep the subsequent layer geometrical size unchanged from the former one. A set of process parameters with a desirability of 0.971 is advised basing on the model when the bead height is expected to be 2 mm and the optimum technological parameters, I_p = 160A, v_T = 0.23 m/min, v_w = 4.91 m/min, have been verified by the confirmatory experiment.