Distortion and Residual Stress Reduction Using Asynchronous Heating Sources for Multi-Robot Coordinated Wire-Arc Directed Energy Deposition

Multi-robot coordinated wire-arc directed energy deposition (MRC-WA-DED) has proliferated in recent decades, employing asynchronous independent heating sources to deposit material simultaneously. Beyond enhancing efficiency, MRC-WA-DED introduces a synergic effect between the heating sources, resulting in a controllable thermal field on the deposit component. This research aims to investigate if the synergic effect is beneficial for residual stress and distortion reduction and how it can be applied to enhance the quality of MRC-WA-DEDed parts. A finite element model was developed to compare the thermodynamic response of WA-DED when both coordinated heating sources (CHSs) and a single heating source (SHS) are applied. Simulation and deposition experiments were carried out to clarify the influence of different coordination strategies on the fabricated component's thermal behavior, stress distribution, and distortion conditions. The results indicate that the synergic effect of CHSs leads to a smoother temperature gradient than that accomplished by a SHS, reducing the maximum distortion of a single layer by 49.1%. As validated by actual depositions, the residual stress, maximum distortion, and hardness of a ten-layer component were reduced by 6.5%, 11.2%, and 18.6%, respectively.