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Laser powder bed fusion (LPBF) additive manufacturing (AM) has been adopted by various industries as a novel manufacturing technology. Powder spreading is a crucial part of the LPBF AM process that defines the quality of the fabricated objects. In this study, the impacts of various input parameters on the spread of powder density and particle distribution during the powder spreading process are investigated using the DEM (discrete element method) simulation tool. The DEM simulations extend over several powder layers and are used to analyze the powder particle packing density variation in different layers and at different points along the longitudinal spreading direction. Additionally, this research covers experimental measurements of the density of the powder packing and the powder particle size distribution on the construction plate. [ABSTRACT FROM AUTHOR]

We address new measurement challenges relating to 3D printing in metal powder using the powder bed fusion technique. Using a combination of confocal microscopy principles and fast, sensitive mid-infrared collection techniques, we present a compact and versatile method of measuring and analyzing broadband thermal emissions from the vicinity of the molten metal pool during the additive manufacturing process. We demonstrate the benefits of this instrumentation and potential for scientific research as well as in situ monitoring. Our compact microscope collection optics can be implemented in various powder bed fusion machines under vacuum or inert atmospheric environments to enable extensions such as multi-color pyrometry or spectroscopic studies of additive manufacturing processes. [ABSTRACT FROM AUTHOR]