Modelling and optimising process of micro-plasma arc freeform fabrication

The main factors limiting the development of wire-based additive manufacturing (w-AM) are deposition process instability and deposition deviation caused by side feed. In this paper, the device tuning accuracy is introduced into the wire-arc deposition model for the first time, a wire-arc stable deposition model in micro-plasma arc directional energy deposition (mPA-DED) was established, and the process of the wire from contacting the micro-plasma arc (mPA) column to conducting stable metal transfer was carefully analyzed. A sensitivity coefficient describing the link between wire size and device adjustment precision in mPA-DED is proposed. The link between the sensitivity coefficient and the maximum meltable wire feeding speed and the threshold value of the maximum stable deposition speed was quantitatively ana-lyzed, and the model was verified by cross-comparison experiments among the design wire size, arc size, and wire-arc position deviation. A well-formed 40-layer curved metal sample with a material area uti-lization ratio of 90.54 % was steadily deposited by using the proposed model and the optimized deposi-tion parameters. This study offers theoretical guidance for designing an online control system for the deposition process to improve the stability of the fabrication process and deposition accuracy in micro-plasma arc freeform fabrication.(c) 2023 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).