Laser Cutting Theory
LASER CUTTING PROCESS
Conventional steels of up to 16 mm lend themselves reasonably well to oxygen assisted laser mating. The kerfs are narrow (as little as 0. 1 mm for thin material) and the resultant heat affected zones are negligible, particularly for mild and low carbon steel. At the same time, the cut edges are smooth, clean, and square.
It has been found that the presence of pockets of phosphorus and sulphur within mild steel can cause burnout along the cut edge, as such, the use of low impurity steels (eg cold rolled) will result in improved edge quality over results obtained with hot-rolled material. A higher carbon content within the steel does yield a slight improvement in edge quality, yet will make the material subject to an increased HAZ.
Since care is taken to control the amount and distribution of additives to the base iron, most alloy steels are considered ideal candidates for the laser cutting process. High strength materials such as AISI-SAE 4130 (chrome moly steel) and 4340 (chrome nickel moly steel) display exceptional laser cut edges that are square and clean.
Similar in many ways to alloy steels, most tool steels respond reasonably well to the cutting action of a laser. The most notable exceptions are the tungsten high speed (Group T) and tungsten hot work (part of Group H) materials which retain heat in a molten state, thereby resulting in burned out and slaggish cuts.