Scan strategy optimization and repeatability testing during laser powder bed fusion additive manufacturing of AlSi10Mg

Scan strategy plays a key role in the densification of laser powder bed fusion (LPBF) processed materials. Still, it garnered less attention from researchers worldwide doing parameter optimization who focus more on quantitative parameters like laser power and scan speed. The repeatability of the LPBF process is also not studied widely, despite being a vital factor in furthering its industrial application. Keeping these gaps in mind, this study investigates the effects of various scan strategies on the densification behavior during LPBF processing of AlSi10Mg. Multiple cubic samples are manufactured using different scan strategies and their relative density analyzed. For each scan strategy, the values of laser power, scan speed and scan spacing were changed as well to provide a comprehensive picture. It was observed that the relative density of the samples increased as more lateral motion was added to the laser path, increasing the lateral overlapping of the tracks. The optical microscopic studies were conducted as well on the polished samples to understand the pore characteristics and microstructural effects of scan strategy variation, which showed that increased lateral motion not only reduced the porosity but altered pore geometry and other characteristics as well. Finally, using the optimized process parameters and scan strategy, multiple samples are manufactured and relative density was calculated to check the repeatability of the process. It was seen that the LPBF process is a highly non-repeatable process as the mean density observed was 99.5126% with mean absolute deviation of 0.1946% and standard deviation of 0.2376%.