Increasing the precision of Laser-Based Powder Bed Fusion by process combination with in situ laser ablation
Manuel Henn, Matthias Buser, Volkher Onuseit, Rudolf Weber, Thomas Graf
Abstract
Laser-based powder bed fusion of metals is limited in terms of achievable accuracy, surface quality, and minimal structure size due to its inherent melting process. The limits are primarily determined by the focal diameter of the laser beam and the grain size of the metal powder. Small structures like deep and narrow slits with a width below 100 µm, are still a major challenge especially for high aspect ratios. To overcome this limitation a quasi-simultaneous manufacturing process combining additive and subtractive laser processes with continuous wave and ultrafast lasers was developed. The additive manufactured components can be precisely machined by means of ultrafast laser ablation after each added layer, achieving detailed structures with feature sizes below 50 µm. In this work, the latest results of the production of narrow slits with a depth of several millimeters in components made of pure iron will be shown.