Adaptive slicing in powder bed fusion of metals using a laser beam-Investigation on productivity, laser absorption, geometrical accuracy, and thermal conditions

Powder bed fusion of metals using a laser beam (PBF-LB/M acc. to DIN EN ISO/ASTM 52900) has reached market maturity. In addition to developing new materials and enabling new applications, the industry focuses on increasing productivity and reducing costs. In this context, increasing the layer thickness can increase productivity but often leads to a deterioration of surface quality and part density. Using variable layer thicknesses depending on the manufactured geometry is well-known from filament-based material extrusion processes and is called adaptive slicing. This study investigates the manufacturing aspects of adaptive slicing using AlSi10Mg. Laser beam reflectance of the different powder layer thicknesses is quantified using diffuse reflectance infrared Fourier transform spectroscopy. The process window is identified and analyzed, focusing on the achievable productivity and required energy input. Furthermore, the suitability of layer thicknesses and processing parameters is analyzed by measuring the dimensional accuracy and process stability of overhanging structures. Heat input, heat dissipation, and potential heat-up are investigated and compared to conventional processes using part-scale thermal simulations. In this study, parameters are developed for layer thicknesses of 120 mu m with an almost threefold increase in productivity in nonoverhanging structures with a part density above 99.7%. Further, adaptive slicing can increase productivity in PBF-LB/M while decreasing the impact on part quality. Future work will focus on automated algorithms to optimize and automize adaptive slicing.