Parametric Study of the Effect of Feed Speed and Power on Laser Cut Quality of 4130 Steel
Samples of 4130 steel were cut by a CO2 laser and the effects of power and feed rate on kerf width, surface roughness, striation frequency and the size of heat affected zone (HAZ) were studied. It was observed that power had a major effect on kerf width and size of HAZ, while feed rate affects were secondary. In the other hand, surface roughness and striation frequency were affected most by feed rate. At low power levels the smallest kerf width and HAZ are obtained and the effect of feed rate is moderate. Low feed rates gave good surface roughness and low striation frequency. For optimum cut quality, kerf width, HAZ and surface roughness are kept minimum. However operating conditions that satisfy these requirements while maintaining high productivity could not be identified.
Effects of Operating Parameters on Surface Quality for Laser Cutting of Mild Steel
Over the last 20 years, laser cutting and drilling, welding, surface heat treatment, cladding, scribing, balancing, and other laser systems have gradually made their way into the industrial workplace. However, there remain significant uncertainties in the understanding of the important physics of laser-material interaction and in material removal processes. Most research focuses on a one- or two-controlling-parameter investigation of cut quality. Furthermore, the implied definition of quality most often involves kerf width and HAZ, not surface roughness. The present work constitutes a quantitative experimental study to determine the effects of cutting speed, assist gas pressure, and thickness on the surface roughness of laser-cut mild steel. The effects of focal plane location and laser power level were also studied through a series of factorial design experiments. This systematic approach, combined with a constraint that a minimally acceptable cut must yield a surface roughness smaller than that produced by a band saw, allowed a large number of operating parameters to be investigated with a moderate number of individual experiments. A unique aspect of the study was the use of wedge-shaped test pieces which were 2.5 cm wide with a thickness varying from 0.05 cm to 0.65 cm over a 15 cm length.more » In this way, surface quality at a given cutting speed could be determined for a range of thicknesses using a single cut.« less
Effects Of Beam-Workpiece-Motions System Interactions On The Working Accuracy Of Laser Cutting Of Sheet Metals
The microscopic and macroscopic working quality attainable during production of finished component parts are discussed in both relationships, the beam-workpiece and the workpiece-motion system interactions. Influences on working accuracy of laser beam characteristics, beam shaping (focussing) system and the guiding behaviour of the NC-machine tool are dealt with. Sheet metals chosen are austenitic, ferritic and carbon steel.