PULSE DEPOSITION METHOD FOR WIRE AND ARC ADDITIVE MANUFACTURING

Abstract

Purpose. To reduce the waviness of the side surfaces of wire and arc additive manufactured parts. Research methods. Two groups of deposited specimens were used. The waviness of the side surfaces was measured from digital images of the cross sections of the specimens. The images were obtained by optical digital scanning. To establish a functional relationship between the geometric parameters of the beads and the main deposition parameters, regression and analysis of variance were performed on the measured data. Results. It was found that different combinations of the main process parameters resulted in a surface waviness of 1.21 ± 0.23 mm. Based on the results obtained, a pulse deposition method was developed. The implementation of regular pauses reduced the heat input and the time spent by the material in the molten state, which limited its distribution. The proposed method resulted in a significantly lower waviness of 0.47±0.08 mm and a significant improvement in the stability of the resulting surface irregularity. Scientific novelty. It has been shown for the first time that the waviness of the side surfaces in wire and arc additive manufacturing does not depend on the main deposition parameters, but is related to the nature of the arc-based deposition process. The developed method of pulsed deposition limits the time the metal remains in the molten state, which reduces the waviness of the surfaces by up to 60% and improves the stability of the geometry by three times, reducing the standard deviation to 0.08 mm. Practical value. Pulsed deposition improves the predictability of the printed geometry by improving the accuracy and quality of the side surfaces. This reduces the required machining allowance, speeds up production, and reduces material waste. In some cases, the predictability of the geometry makes it possible to eliminate post-processing.