Laser polishing of 3D printed metallic components: A review on surface integrity

Abstract 3D Printing is an emerging technology to fabricate complex components in less lead time compared to traditional manufacturing processes. 3D printing enables to build metallic functional components directly from CAD model by depositing the material layer by layer. The fabricated components generally have very rough surfaces and demands for post processing, so that it can directly employ for its end use. Owing to drawbacks like time consuming, skilled labour requirement and limited scope of automation, conventional finishing processes find less application for finishing freeform components. Laser Polishing is a highly productive, contactless and fully automatic post processing technique which is giving promising results to lower the surface roughness of 3D printed metallic components from the past two decades. In laser polishing, when the components are irradiated by the laser radiation, peaks of the surface are melted to a very thin layer and redistributed into the valleys by surface tension and gravity. Laser polishing has shown its ability to polishing varieties of materials from reflective materials like aluminium to high strength materials like Inconel and Titanium alloys. In this present article, a review of laser interaction on surface integrity and mechanical properties of different materials used in metallic 3D printing are reported. The optimum process parameters of laser polishing like laser power, beam diameter, scanning speed and scan spacing/step over are also mentioned with respect to each material.