The Effects of Vibration and Pulsation on Metal Removal by a Plasma Torch

An experimental study has been carried out on the effects of workpiece vibration and gas pulsations on metal removal rates using plasma jets. In the case of workpiece vibration, increases in removal rates of up to 30 percent were found, which can be accounted for in terms of capillary waves set up in the melt. The influence of pulsation of gas flow velocity and arc current at modulation levels of 10 percent was found to be negligible. A theoretical model has been developed which explains the results in terms of the development of resonance capillary waves in the molten metal and predicts the average depth of the layer of molten metal.