Dynamic optical beam shaping system to generate Gaussian and top-hat laser beams of various sizes with circular and square footprint for Additive Manufacturing applications
Gebirie Y. Belay, Yannis Kinds, Louca Goossens, Kopila Gurung, Niels Bosmans, Reginald Diltoer, Jeroen Eraly, Michael Vervaeke, Hugo Thienpont, Brecht Van Hooreweder, Jürgen Van Erps
Abstract
The speed of production in laser-based additive manufacturing processes is rather low compared to conventional manufacturing methods and could be improved by using a top-hat laser beam intensity profile, a variable spot size or a combination of both, enabling wider melt pools during processing. This while retaining or possibly even improving part quality. In this work, the design and implementation of a dynamic optical beam shaping system is presented to enable different shapes and sizes of top-hat beams at the build platform of a Laser Powder Bed Fusion machine which is equipped with a fiber laser emitting at 1070nm. The system has been demonstrated by assembling custom-made beam shapers with commercially available beam expanders and by measuring the intensity profiles. Initial results indicate the possibilities for tuning of the spot size at the build platform by a magnification factor ranging from 1x to 4x. Parameter optimization for the Gaussian beam with 4x magnification was performed and a first 316L demonstrator part is further discussed in this work to illustrate a gain in productivity of 44%, while retaining >99% density.