Fluctuations of Tracks and Layers during Aluminium Laser Powder-Bed Fusion

Abstract

Laser Powder-Bed Fusion (LPBF) is one method in Additive Manufacturing where layer-wise complex structures can be built. However, although the LPBF machines produce promising parts, the efficiency and process speed are typically still low, which can make the process expensive and uneconomical. Recent research showed that volume elements in the parts can be melted several times, while only a small material volume is added, which indicates a high loss of energy. In order to understand the process better, in this work, theoretical modeling and smart powder-bed experiments were designed to explain the impact on the track dimensions based on the previously built tracks and layers. It was found that the powder availability varies for each track and has an alternating character within and between layers. The comparison of the simulation and experimental results indicates that the powder pick-up from neighboring powder volumes is the main reason for the variations of the powder availability.

Keywords

• selective laser melting
• additive manufacturing
• 3D printing
• part density