Tailoring porosity and surface quality in laser powder bed fusion via variable focal intensity shaping

Maiwald F, Tumkur TU, Weiß F, Matthews MJ, Hierl S, Schmidt M (2026)

Publication Type: Conference contribution

Publication year: 2026

Journal

Procedia CIRP Curran

Publisher: Elsevier B.V.

Book Volume: 143

Pages Range: 578-583

Conference Proceedings Title: Procedia CIRP

Event location: Heinrich-Lades-Halle, DEU

DOI: 10.1016/j.procir.2026.07.122

Abstract

Shaping the spatial intensity profile of the process laser beam is a promising approach for improving part and surface quality in laser powder bed fusion. However, practical implementation is limited by logistical or economic constraints, since the process beam shape needs to be adapted depending on the material and print process conditions, often involving specialized laser sources or complex optical setups. Here, a single refractive focal beam shaping optic is employed to realize laser beam intensity variations of Gaussian, flat-top (tophat) and annular (ring) beams by controlled defocusing. Additionally, a conduction-mode thermal model using measured beam profiles and temperature-dependent properties is implemented. The model correlates well with published single-track melt pool dimensions for Gaussian and ring beams and predicts lack-of-fusion defects. The observations indicate that tophat and shallow ring beam profiles lead to a smaller spread of part density values in SS 316L across low to moderate energy densities, compared to other beam profiles explored in the study. Topographical characterization of the top surfaces indicates that tophat beams exhibit superior surface quality (lower roughness).

Authors with CRIS profile

Michael Schmidt Lehrstuhl für Photonische Technologien (LPT)

Involved external institutions

Ostbayerische Technische Hochschule Regensburg (OTH) DE Germany (DE) Lawrence Livermore National Laboratory US United States (USA) (US)

How to cite

APA:

Maiwald, F., Tumkur, T.U., Weiß, F., Matthews, M.J., Hierl, S., & Schmidt, M. (2026). Tailoring porosity and surface quality in laser powder bed fusion via variable focal intensity shaping. In Procedia CIRP (pp. 578-583). Heinrich-Lades-Halle, DEU: Elsevier B.V..

MLA:

Maiwald, Frederik, et al. "Tailoring porosity and surface quality in laser powder bed fusion via variable focal intensity shaping." Proceedings of the 14th CIRP Conference on Photonic Technologies, LANE 2026, Heinrich-Lades-Halle, DEU Elsevier B.V., 2026. 578-583.

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