Laser spot size and scaling laws for laser beam additive manufacturing

Published

November 3, 2021

Author(s)

Jordan Weaver, Jarred C. Heigel, Brandon Lane

Abstract

Laser powder bed fusion (L-PBF) additive manufacturing (AM) requires the careful selection of laser process parameters for each feedstock material and machine, which is a laborious process. Scaling laws based on the laser power, speed, and spot size; melt pool geometry; and thermophysical properties can potentially reduce this effort by transferring knowledge from one material and/or laser system to another. Laser spot size is one critical parameter that is less well studied for scaling laws compared to laser power and scan speed. Consequently, single track laser scans were generated with a spot size (D4σ) range of 50 μm to 322 μm and melt pool aspect ratio (depth over spot radius) range from 0.1 to 7.0. These were characterized by in-situ thermography, cross-sectioning, and optical microscopy. Scaling laws from literature were applied and evaluated based on melt pool depth predictions. Scaling laws that contain a minimum of three dimensionless parameters and account for changing absorption between conduction and keyhole mode provide the most accurate melt pool depth predictions (< 35 % difference from experiments), which is comparable to thermal simulation results from literature for a select number of cases.

Citation

Journal of Materials Processing Technology

Pub Type

Journals

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DOI Link

Keywords

absorption, Inconel 625, melt pool, thermography, keyhole

Citation

Weaver, J. , Heigel, J. and Lane, B. (2021), Laser spot size and scaling laws for laser beam additive manufacturing, Journal of Materials Processing Technology, [online], https://doi.org/10.1016/j.jmapro.2021.10.053 (Accessed April 25, 2024)