Analysis of material removal on metallic materials by pulsed fiber lasers

Pulsed fiber lasers are being extensively used for micromachining applications on a very broad range of metallic materials. End user requirements can vary greatly based on whether the parts are functional such as mold tools or just provide deep engraved alphanumeric marking. Material removal rates and residual surface quality are greatly affected by the laser pulse parameters and the optical arrangements used. This study reviews the effects of 4 different beam qualities as defined by their M2. A range of different optical configurations were also used to allow for direct comparison using the same optical power densities. A nominal standard etch pattern was modified by focus, scan speed, fill density and focal depth. They were etched into and analysed on five different materials: raw aluminium, anodised aluminium, mild steel, stainless steel and hardened tool steel. The most extensive data presented is on Aluminium where the differences are most distinct.An additional discussion is provided regarding the limits of mechanical measurement of etch depth. Variations between contact and compression methods are presented.The results of this study show that at the same average power, higher repetition frequency less energetic pulses can remove more material per second than higher energy pulses at lower frequencies. The impact of beam quality and spot size along with machining strategies are discussed and compared with regards to material removal rates and residual feature and surface quality.Pulsed fiber lasers are being extensively used for micromachining applications on a very broad range of metallic materials. End user requirements can vary greatly based on whether the parts are functional such as mold tools or just provide deep engraved alphanumeric marking. Material removal rates and residual surface quality are greatly affected by the laser pulse parameters and the optical arrangements used. This study reviews the effects of 4 different beam qualities as defined by their M2. A range of different optical configurations were also used to allow for direct comparison using the same optical power densities. A nominal standard etch pattern was modified by focus, scan speed, fill density and focal depth. They were etched into and analysed on five different materials: raw aluminium, anodised aluminium, mild steel, stainless steel and hardened tool steel. The most extensive data presented is on Aluminium where the differences are most distinct.An additional discussion is provided regarding the l...