Laser Line Profile Scanning for Powder Bed Topography Measurement

The metal additive manufacturing (AM) method of laser powder bed fusion (LPBF) relies upon the formation of uniform, densely packed, and defect free powder layers. The direct measurement of as-spread powder layer quality is challenging owing to the fine size of the powder bed features and limited selection of instruments which can assess the powder bed in-situ. This work assesses the fitness of a laser line profiling instrument in the topographical measurement of an LPBF system powder bed. Firstly, results which assess the minimum resolvable feature size are presented, which suggest the instrument can capture microscopic powder bed defects. The ability of the instrument to detect macroscopic powder bed defects is also shown. Measures of bed quality, based on areal surface texture analysis, are explored for their potential as process signals.Mechanical Engineerin