Electric Arc Augmentation Of The Laser Cutting Of Mild Steel

The performance limits of the oxygen-assisted laser cutting of mild steel have been extended by the incorporation of an electric arc in the laser cutting process. It is shown that cutting performance (as determined by cutting speed) increases with arc power and approximately 100$ increase in cutting performance can be obtained without any significant deterioration of cut quality. At high arc powers (greater than about 4kw), although cutting speed increases as the arc power increases, the cut quality (as determined by the kerf width and heat affected zone measurements) decreases remarkably. The laser beam and the electric arc were used on opposite sides of the same workpiece and the deterioration in cut quality was restricted to the arc's side. Although the laser-arc interaction phenomena are not yet fully understood, the results from the experiments reported in this paper indicate a cooperative mechanism between the laser and the arc. The electric arc provides a cheap additional energy source to the laser energy absorbed by the workpiece while arc stability is maintained at high arc speeds when the arc on its own would be unstable. This increase in arc stability is caused by a laser-generated hot spot on the same side of the workpiece as the arc. The laser-generated hot spot provides a low resistance path for the arc to root into.