Data-driven control of slicing thickness in wire directed energy deposition via on-line monitoring the shifting behavior of arc voltage drop

Accurate monitoring of layer deposition height and adjustment of slice thickness are crucial for large-scale structures in wire directed energy deposition (Wire DED). However, the inherent complexity of arc behavior introduces instability in electrical signals, particularly under varying arc modes. This study investigates arc voltage drops during Wire DED and their nonlinear dynamics under different slice thicknesses. Statistical analysis of raw electrical signals using kernel density estimation effectively captures voltage characteristics that reflect the state of the arc. These voltage features exhibit significant correlations with the contact tip to work distance (CTWD). Furthermore, high-speed imaging and computational fluid dynamics (CFD) simulations were employed to explore the dynamic behaviors of the arc and shielding gas under varying slice thicknesses. The findings reveal that slice thickness directly influences CTWD and affects the flow dynamics of shielding gas. Variations in air ingress into the arc zone led to the shifting of arc voltage drops. Consequently, a novel approach is proposed to monitor and adjust slice thickness by establishing correlations between CTWD and arc voltage signals. The experimental validation of this method on typical structures and its subsequent application in the additive manufacturing of 10 m-class connecting ring of heavy-duty carrier rocket have demonstrated its efficacy and potential. These findings suggest that the method has the potential for application in additive manufacturing across a range of sectors, including aeronautics, spaceflight, and shipbuilding.