Dynamic plasma behavior and melt pool evolution on inclined electric arc machining

The effect of surface inclination on plasma–material interaction and melt pool evolution during electric arc discharge machining remains insufficiently understood. This study investigates plasma behavior and melt pool morphology under single-pulse discharge at inclination angles of 0°, 30°, 45°, and 60°, using a combination of experiments and simulations. A high-speed camera was employed to record plasma displacement. In parallel, a two-dimensional model was developed to simulate temperature distribution, evaporation recoil pressure, and melt flow. Results reveal that increasing inclination promotes plasma upward deflection, producing asymmetric heat flux and melt pool deformation. Simulations show that the upper bulge elongates and lowers, whereas the lower bulge shortens and rises. At 60°, the bulge length asymmetry reaches 35.96%. Metallographic analysis indicates that recast layer distribution shifts with inclination: at 0°, it is thickest at the center (25.92 μm) and thinnest at the edges (4.55–4.95 μm), while at 45°, it becomes thicker at both ends and thinner in the middle. Experimental–simulation comparisons demonstrate high consistency in melt pool size, offset direction, and asymmetry trends, validating the accuracy of the numerical model. The results indicate that greater inclination shifts plasma upward, causing uneven heat input and melt pool deformation. Melt flow, driven by evaporation recoil pressure, gravity, and temperature gradients, becomes highly directional, leading to melt pool offset and irregular bulge formation.