TWI Industrial Member Report Summary 846/2006
By H Graham
Cutting is an important application for industrial lasers, currently dominated by the use of CO2 lasers for the cutting of steels, in thicknesses from less than 1mm, to 15-20mm in some specialist job shops. Industries using laser cutting widely for thicker steel applications (6mm and above) include shipbuilding, structural steelwork, and off highway vehicles. Market drivers for these industries include the need to process thicker material, maximise cutting speeds, and reduce rejection rates.
'Laser' grades of steel with altered chemical composition are commercially available, which are claimed to give improved cutting performance. However, previous work at TWI has shown that while there are certainly effects of material composition, the surface quality of the steel also has an effect on the quality of the cut edge. In particular, certain mill scales, the tightly adherent oxide layers formed during rolling of the steel, were found to be beneficial in improving cut edge quality. However, it would appear that the effect of different surface conditions on cutting performance is acknowledged by industrial users, but not well understood. This project was initiated to examine the effects of material surface condition on laser cutting in more detail than had been carried out before.
To compare the relative effects of surface quality and steel type on the laser cutting performance of structural steels.