ANALYSIS AND EFFECTS OF AIRFLOW DISTRIBUTION ON LASER POWDER BED FUSION

Abstract

Advanced manufacturing has experienced a rapid increase in modern industrial practices over the last few decades. At the forefront of this growth is metallic 3D printing, specifically, laser-powder bed fusion (LPBF). The advanced and sensitive nature of LPBF requires fine-tuning of process variables – one of those being argon gas distribution throughout the build chamber. The objective of this thesis is to discuss the design and measurement data obtained from an airflow measurement device installed within the build chamber of a General Electric (GE) Concept Laser M2 Series 5 metal 3D printer – a pilot study into the effects of airflow on the LPBF process. The device collected 1,000 data points across the volume directly above the surface of the build plate at three airflow velocities: low (1.95 m/s), nominal (2.05 m/s), and high (2.15 m/s). The airflow device was constructed from simple 3D printer hobby materials. The pitot tube and mechanical components were controlled using external computers and original code written for this data acquisition. The testing focused on 4 critical zones: front edge of the plate, just inside the front edge of the plate, the centerline of the plate and the trailing edge of the plate. These measurement points produced figures that showed channels of ideal airflow and areas of poor distribution throughout the chamber. The airflow data was compared to previously measured mechanical strength data to determine the ideal printing conditions. Overall, the pilot study found that airflow differences did not result in notable print quality differences; however, they presented enough evidence to suggest ideal conditions and plate placements for sensitive print requirements. The purpose of these results is to set a foundation for future research into airflow conditions and do not provide any concrete conclusions.