Laser Micro-polishing of Stainless Steel for Antibacterial Surface Applications

In this work laser micro polishing (LMP) of cold rolled 0.3 mm thick 304 stainless steel with a pulsed fibre laser is studied, for applications where antibacterial properties are required. Due to its production method, the initial surface roughness of the tested material was considerably low (Sa=85.3±2.8 μm), rendering a demanding case for the laser polishing process. Accordingly, process feasibility under three different atmospheric conditions, namely ambient, Ar and N2 atmosphere, was investigated. A large set of process parameter combinations was tested and initial analysis was carried out to identify the polishing feasibility by inspection under an optical microscope. Once the feasibility window was determined, a primary characterization was made on selected surfaces for roughness and waviness. Results show that in some process conditions belonging to the explored feasibility range, surface roughness could be decreased by 50%.