Modifying the heat-force transfer to increase geometric consistency in arc-DED

The heat-force output characteristics are the key factors for determining deposition geometric consistency. This study innovatively introduces an alternating arc technology based on polarity-switching self-adaptive shunting (PSSAS), aiming to optimize the heat-force output characteristics and deposition geometric consistency for aluminum alloys. By comparing the arc pressure of traditional variable polarity plasma arc (VPPA) and PSSAS, it was observed that PSSAS exhibits a significantly reduced arc pressure. The difference in arc pressure between PSSAS and VPPA increased from 0.034 kPa at 70 A to 0.202 kPa at 110 A. Additionally, the arc pressure of PSSAS and VPPA demonstrated a higher sensitivity to changes in current but a lower sensitivity to the duty ratio. The PSSAS effectively reduces the electromagnetic force and plasma jet force acting on the workpiece, resulting in a narrower and taller deposition layer morphology. During single-pass multi-layer deposition, the reduced heat-force output of the PSSAS, combined with the increased heat dissipation area, accelerates the achievement of thermal equilibrium within the deposition layer, resulting in a stable average layer height of 2.9 mm-3.4 mm, which surpasses the 1.9 mm-2.4 mm observed in VPPA.