Improvement of Surface Quality and Process Area Rate in Selective Laser Melting by Beam Oscillation Scan Technique

Abstract

Selective laser melting (SLM) has potential benefits for additive manufacturing of complex and precise metal parts with required mechanical and material properties. However, the improvement of surface quality and the minimization of fabrication time still remark a challenge for efficient manufacturing by SLM. Among the process parameters, the scan strategy has a significant influence on process stability and quality of the final manufactured three-dimensional products. This paper demonstrates the investigation of an alternative scan strategy to improve the surface quality with a reduction of fabrication time and laser energy input. Hereby, the scan strategy is performed by a conventional linear and oscillating laser beam movement in a self-developed SLM process chamber. Comparative analysis of the manufactured specimens regarding surface quality and density was performed. The investigations in oscillating laser beam movement show a decrease in the average variation of surface profile up to 50% relative to the experimented conventional linear scan technique. Due to an increased melt pool during the oscillation beam movement, the hatch distance was increased. As a result, the applied laser energy input was reduced by more than 28%, and the area rate was raised up to 50% compared to the conventional linear laser beam movement.