Influence Mechanism of Arc Characteristics on Droplet Transfer Behavior in CMT-based Additive Manufacturing

doi:10.3901/JME.2023.15.267

Abstract

Abstract: Cold metal transition (CMT) arc additive manufacturing technology has the advantages of high deposition efficiency and low manufacturing cost, which has a broad application prospect in the rapid prototyping of large-scale components for aviation. A higher current is needed to improve the deposition efficiency for arc additive manufacturing large-scale components. However, the projected transfer behavior under the high current mode and the influence mechanism of the arc discharge process on droplet transfer frequency is not explicit. Therefore, the arc shape and droplet transfer behavior in the CMT process is observed through a high-speed camera in our study. Meanwhile, the droplet transfer frequency and droplet size under different current waveforms and process parameters are analyzed by establishing the arc discharge and droplet transfer model. Finally, the impact mechanism of physical factors such as current density and Lorentz force on droplet transfer in the arc discharge process is revealed. The results show that the arc width and Lorentz force determine the force on the droplet in the process of arc discharge and then determine the droplet size and its transition frequency. The duration of the current peak value increases by about one time when the wire feeding speed increases from 5.5 m/min to 7.0 m/min. Meanwhile, the electromagnetic force increases with the rise of arc width and current density. It causes the droplet size decreases by 14%, and the droplet transfer frequency increases by 3-4 times. When the current waveform enters the arc extinguishing stage, the droplet transfer mode changes to short-circuit transition. The short-circuit transition frequency decreases from 29 Hz to 20 Hz with the increase of wire feeding speed.

Key words: wire arc additive manufacturing, droplet transfer, arc morphology, current and voltage wave, numerical simulation

CLC Number:

TG156

LÜ Feiyue, WANG Leilei, GAO Zhuanni, DOU Zhiwei, BEN Qiang, GAO Chuanyun, ZHAN Xiaohong. Influence Mechanism of Arc Characteristics on Droplet Transfer Behavior in CMT-based Additive Manufacturing[J]. Journal of Mechanical Engineering, 2023, 59(15): 267-281.

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