Efficient LPBF-process development by Design of Experiments

Design of experiments (DoE) can support development of LPBF processes for unknown materials in the planning and evaluation phase, and the further optimization of the process performance. Two different DoE’s, full factorial DoE and D-Optimal DoE with 64 and 18 samples, respectively, have been applied to the process development of FeNi36. The impact of the major process parameter and their potential interactions is identified and their significance on the target value porosity is evaluated. Both DoE’s display equal key findings and allow to separate the process regions of lack-of-fusion porosity and keyhole dominated porosity. The major LPBF parameter affect the resulting porosity in a different way: while laser power and scan velocity should be adjusted carefully, hatch spacing in of less importance to achieve highest porosity values. Furthermore, interactions between different parameter and saturation effects must be considered. Application of DoE to LPBF process development allows to dramatically reduce the experimental effort without loss of accuracy and shows large potential for cost reduction in process development purposes for new materials.