Selective removal of steel by a laser slotting process

Abstract

Laser welding, cutting and surface treatment have become accepted means of processing materials. The future integration of lasers and machine tools would be supported by the development of a laser machining process. At present laser systems are used to selectively remove material by melting and evaporation followed by ejection with high speed gas jets. Removing material by melting and evaporation leads to very low wall plug efficiency and the process has difficulty competing with conventional mechanical removal methods. If mechanical removal methods are incapable of performing the required task then efficiency is not so important. However, mechanical removal methods are capable of performing the majority of machining processes. When processing high tensile steels and super alloys the situation becomes rather different, here mechanical methods are slow with tool wear becoming a major problem. Adopting a laser solution would seem appropriate but efforts must be made to avoid bulk melting and vaporisation regimes in order to maximise efficiency. This paper examines the new process of laser slot cutting (laser slotting). The laser is used to remove material to a given depth in the form of a narrow slot (blind cut). Slot forming mechanisms and some process variables are discussed. Methods of bulk removal through multi-slot production are also presented.Laser welding, cutting and surface treatment have become accepted means of processing materials. The future integration of lasers and machine tools would be supported by the development of a laser machining process. At present laser systems are used to selectively remove material by melting and evaporation followed by ejection with high speed gas jets. Removing material by melting and evaporation leads to very low wall plug efficiency and the process has difficulty competing with conventional mechanical removal methods. If mechanical removal methods are incapable of performing the required task then efficiency is not so important. However, mechanical removal methods are capable of performing the majority of machining processes. When processing high tensile steels and super alloys the situation becomes rather different, here mechanical methods are slow with tool wear becoming a major problem. Adopting a laser solution would seem appropriate but efforts must be made to avoid bulk melting and vaporisation re...