Laser Cutting Theory
LASER CUTTING PROCESS
Lasers have been shown to be viable cutting tools for the fabrication of sheet metal components made from stainless. The controlled heat input of the laser beam serves to minimise the HAZ along the cut edge, thereby helping the material to maintain its corrosion resistance. Since stainless does not react with an oxygen assist as efficiently as does mild steel, cutting speeds for stainless are slightly slower than those for comparable thicknesses of plain steel. At the expense of up to 50% of the speed for oxygen assisted cutting, an inert assist gas can be employed to obtain a “weld ready”, oxide-free cut edge.
As for the resultant cut quality, martensitic and ferritic (400 series) stainless provides clean smooth edges. The presence of nickel within austenitic (300 series and precipitation hardened) stainless steels affects the energy coupling and transfer within the material. Specifically, the viscosity of molten nickel generated during the cutting action causes it to migrate and adhere to the backside of the cut. While the use of high velocity gas jets can effectively eliminate slag for material up to 1.0 mm thick, slag deposits up to 0.5mm are generally present on thicker cross sections.