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Item type:Publication, Access status: with files , Systematic study of the interplay between laser beam shape, energy input, and hatch spacing in PBF-LB/M of Ti-6Al-4V: experiments and numerical modeling(Elsevier, 2026-07-17); ; ; ; Programmable laser beam shaping tailors the spatial irradiance distribution in laser powder bed fusion (PBF-LB/M), enabling control over melt-pool geometry and defect formation. However, the coupled effects of beam shape, hatch spacing (track overlap), and energy input on densification and microstructural development remain insufficiently understood. Accordingly, Ti-6Al-4V is studied using single-track experiments, cube builds, and 3D transient multiphysics simulations across three ring-type beam profiles ranging from relatively core-weighted to strongly ring-dominated. Single tracks spanning a power–speed matrix (linear energy density, P/v) quantified melt-pool width, depth, and molten area and mapped stability regimes (fragmentation, necking, stable) and transition thresholds with increasing energy input. Cube specimens mapped relative density versus beam mode, areal energy density AEDh = P/(v h) (J/mm2), hatch spacing h, and geometric ratios h/d (d: effective beam diameter) and W/h (W: melt-pool width). Near-full density (~99.9%) was achieved for all profiles at AEDh ≥ 2.8–3.0 J/mm2; relatively more core-weighted profiles reached this at lower AEDh, whereas ringdominated profiles required higher input to suppress lack-of-fusion. Density dropped when h/d≳1, while W/h≳ 1.2 preserved high density. Microstructure and Vickers microhardness (HV0.2) were assessed across AEDh. All conditions exhibited martensitic α′ microstructures, and microhardness remained ≈360–395 HV0.2, converging once near-full density was reached. Simulations showed that ring-dominated density loss arises from insufficient inter-track remelting depth (cusp formation) despite lateral overlap, requiring higher overlap ratios for full fusion. Thermal gradients (G) and solidification rates (R) placed all cases in the columnar growth regime; higher G/R in more core-weighted profiles is consistent with stronger grain continuity than the more refined ringdominated structures.Publicationtype: Journal Article9 15 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Advancing laser powder bed fusion of metals via tailored laser beam shaping: a critical reviewLaser beam shaping is increasingly explored to enhance Laser Powder Bed Fusion of Metals (PBF-LB/M) by controlling the spatial energy distribution within the laser spot. While conventional Gaussian beams remain widely used in commercial systems, their concentrated energy input can promote steep thermal gradients and localized overheating, which may restrict process stability, productivity, and part quality. This review critically synthesizes recent progress in laser beam shaping for PBF-LB/M, with emphasis on work from 2020 to early 2026. Compared with earlier reviews that mainly focused on optical implementation or broader laser–material processing concepts, this review integrates beam-shape generation with melt-pool dynamics, defect formation, surface quality, microstructural evolution, mechanical response, productivity, and emerging shape-aware process descriptors. The discussion shows how profiles such as core–ring, ring-dominant, top-hat, and elliptical beams can broaden stable process windows, suppress spatter and keyhole porosity, and promote more uniform thermal histories, with implications for surface quality, mechanical isotropy, and build efficiency. Modeling and simulation studies are also summarized to clarify the coupled heat-fluid–solid interactions controlling melt-pool behavior, thermal gradients, and solidification kinetics. Furthermore, major implementation challenges such as optical integration, energy-delivery stability, process reproducibility, and the lack of standardized beam descriptors are summarized. The review concludes by outlining emerging research directions aimed at enabling practical, reliable, and industrial-scale adoption of beam-shaping technologies in additive manufacturing.Publicationtype: Review Article15 23 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Surface roughness formation in powder bed fusion of copper using Gaussian and ring-shaped laser beam profilesBoth Gaussian laser beam profiles and ring-shaped laser beam profiles demonstrate the capability to produce specimens with a part density of more than 99.5% and an electrical conductivity above 99% compared to the International Annealed Copper Standard (IACS) in powder bed fusion of copper using a laser beam (PBF-LB/M/Cu). However, the influence of the beam profile on the surface roughness and surface characteristic has not yet been investigated in detail. In order to close this gap, inclined cube geometries are manufactured with varying laser power and scan speed using a Gaussian and ring-shaped beam profiles. The results reveal that the beam profile achieving the lowest surface roughness Sa in the investigated parameter range depends on the surface orientation. For the down-skin surfaces, the use of ring-shaped beam profiles reduces the surface roughness Sa by up to 29.9% compared to the Gaussian beam profile, whereas the surface roughness Sa for the up-skin and side surface is more than doubled. This is related to differences in surface roughness formation of the Gaussian and ring-shaped beam profiles, which are discussed in detail. For all investigated beam profiles, changes in the height of the peaks, depth of the valleys and the number of attached particles on the surface are observed with varying laser power and scan speed. Furthermore, a trend between the surface roughness Sa of the inclined cube geometry and the aspect ratio R of the weld geometry is found, indicating that the welding regime influences the surface roughness.Publicationtype: Journal Article14 25 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Industrialization of additive manufacturing(Wiley, 2025-01-13); ; ; ; Jankowiak, MircoOur world is constantly facing a wide variety of social challenges – currently, issues such as climate change, security, demographic change, and resource conservation are of significant importance and show an acute need for action. Disruptive technologies, among other things, are needed to tackle such problems. Additive manufacturing (AM) is regarded as the ‘game changer / paradigm shift’ technology for the digital, automated production of the future – as the key enabler of ‘Production 2.0’.Publicationtype: Journal Article15 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Laser powder bed fusion of pure copper using ring-shaped beam profiles(American Institute of Physics (AIP), 2024-09-23); ; Additive manufacturing of copper using laser powder bed fusion (PBF-LB/M) enables the production of highly complex components. However, processing of copper by means of near-infrared laser radiation is challenging due to its absorptivity of only 5%-20%. Using a keyhole welding process with a Gaussian intensity distribution increases the absorptivity up to 53% due to multireflection. This enables the production of components with a density larger than 99.5% and electrical conductivity larger than 90% of the International Annealed Copper Standard (IACS), but this type of welding leads to keyhole porosity due to keyhole instabilities. One way of counteracting is the use of a heat conduction welding process. However, due to the Gaussian intensity distribution, it is not possible to supply sufficient energy to eliminate lack-of-fusion porosity and concurrently avoid the formation of a keyhole. Ring-shaped beam profiles have proven their advantages in stabilizing the PBF-LB/M process with a tendency toward higher laser power, but pure copper has not yet been processed in this way. Therefore, this study investigates the potential of three ring-shaped beam profiles to produce specimens with a density of more than 99.5% and their respective electrical conductivity using a laser power of up to 1300 W. In order to understand the underlying welding process, the weld geometry of single-tracks is analyzed. Specimens with a density of up to 99.77% and an electrical conductivity of up to 101.62% IACS are produced, whereby the material properties and welding regime depend on the selected ring-shaped beam profile.Publicationtype: Journal Article29 38 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Achieving high strength and ductility in Inconel 718: tailoring grain structure through micron-sized carbide additives in PBF-LB/M additive manufacturing(Taylor & Francis, 2024-09-11); ; ; ; Few attempts have been made so far to develop modifiers for in situ use in Inconel 718 PBF-LB/M fabrication. Reports show an increase in tensile strength compared to unmodified counterparts. However, significant ductility reduction is observed, outweighing the mere tensile strength improvements when considering practical applications. In this study, micron-sized powder modifiers (NbC, TiC, and B4C) were added in proportions of 0.6 wt.% (NbC and TiC) and 0.2 wt.% (B4C) to Inconel 718 powder for PBF-LB/M processing. These modifiers allowed for grain structure control during heat treatment, including hot isostatic pressing. The addition of NbC resulted in a finer grain structure, while the addition of TiC preserved the as-built grain structure after heat treatment. Carbide precipitates led to uniform GND distribution and promoted uniform stress distribution. We show that the trade-off between strength and ductility in carbide-modified IN718 can be overcome by careful PBF-LB/M processing and heat treatment.Publicationtype: Journal Article14 83 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Prozessstabile additive Fertigung durch spritzerreduziertes LaserstrahlschmelzenPublicationtype: Doctoral Thesis37