Abstract
One of the main factors keeping additive manufactured metal parts from being used in industry is the relatively low fatigue life of the as-printed parts when compared to their conventionally manufactured counterparts. In addition, certain areas on additively manufactured parts need finishing operations in order to make them functional. While laser polishing has demonstrated the ability to reduce the roughness of various metal surfaces, including additive manufactured ones, it is necessary to study the influence of this process to ensure the surface roughness improvements are not gained at the detriment of fatigue life. The objective of this work is to determine the influence of laser polishing on the fatigue life of both conventionally and additively manufactured metal parts. Fatigue samples were generated from 316L stainless steel using conventional machining and additive manufacturing through laser powder bed fusion. A single set of laser polishing parameters was used to determine the influence of laser polishing on samples manufactured from both methods. This work has shown that surface roughness of both machined and additive manufactured parts can be reduced without sacrificing fatigue life under certain polishing conditions. This demonstrates that laser polishing is a practical method for addressing additively manufactured surface roughness challenges while not negatively impacting fatigue performance.