LASER WELDING


is on the solid–liquid interface, the entrapped vapour becomes a pore [7,9]. Further validation can be found in [7].


DOWN THE OPTICAL PIPELINE


The development roadmap targets new areas such as additional wire and powder feeds, an open-source library for custom beam shaping, explicit residual stress calculations, magnetohydrodynamics for weld- pool control and plasma ionisation. As an open platform, these capabilities will continue to evolve alongside the research community. For more detail and to access the code, visit laserbeamfoam.com.


Figure 3: Laser Welding (4.0 kW, 4 m/min, 560 μm spot size). (a) Longitudinal weld cross section, (b) Isometric overview, (c) Weld cross section and characteristic velocity vectors and (d) Porosity formation mechanism [7, 9].


melt due to the vapour phase is described by a phenomenological recoil pressure term. It captures effects due to surface tension, Marangoni forces, latent heat, buoyancy of phase thermal expansion (a Boussinesq approximation), and momentum damping due to solidification. A ray-tracing algorithm turns an incident Gaussian laser beam into rays that are tracked through their multiple reflections as shown in Figure 1, with the energy deposited by each ray determined through Fresnel equations. ‘compressiblelaserbeamFoam’ applies the same framework; however it explicitly captures the transitions between liquid and vapour phases for the chemical components specified (eliminating the phenomenological recoil pressure term approximation).


Additionally, both solvers can capture the multi-component nature of mixing between alloys, enabling their use for simulating dissimilar laser joining and powder bed processes. Multiple simultaneous incident laser sources on a metallic substrate can also be simulated [5]. Practically Laserbeamfoam runs on OpenFOAM v2506 (Linux) and output from the solver can be viewed in Paraview. Users can manipulate optical parameters from laser power, path, speed, wavelength, incidence, radius, radius definition (1⁄e2


of total radius), pulse and the total number of rays.


X-RAY VISION


Flint et al. [6] and Bunaziv et al. [7] have highlighted key validation cases of the incompressible ‘laserbeamFoam’ solver. Ultra-high speed synchrotron X-ray imaging of laser welding in Ti–6Al–4V (IPG YLR- 500-AC Yb Fibre laser 1070 nm, power = 156 W, spot size = 140 µm) results are compared as shown in Figure 2. The simulations predicted the experimentally observed pool geometry, penetration rate, and oscillation frequencies of the keyhole. This validation demonstrated the solver’s ability to predict realistic thermo-capillary and fluid dynamic behaviour within the melt pool [6,8].


or 95%


Bunaziv et al. used the solver to study aluminium laser beam welding, benchmarking against an existing X-ray synchrotron study on AlMgSi (AA6082) alloy. Laser welding porosity was investigated, and simulations were compared to X-Ray synchrotron data of a 4 kW fibre laser weld (TRUMPF TruDisk 16001 Yb:YAG disk laser 1030 nm, speed = 4m/min, beam diameter = 560 μm) in an Argon gas layer on AlMgSi (AA6082) Alloy, which showed good agreement with experimental results (Figure 3). This showed role of keyhole dynamics in pore formation, specifically, periodic transitions from slender (“I-like”) to root-bulged (“J-like”) keyholes. These bulges form immediately before collapse and rapid redrilling. When the bulge


REFERENCES


[1] D. Rosenthal, Welding Journal 20 220-234, 1941


[2] J. Mazumder and W. M. Steen, J. Appl. Phys. 51 (2) 941-947,1980


[3] M. Jiménez-Xamán et al., Front. Mech. Eng. 10, 2024


[4] A. Otto et al. arXiv:2509.22666 [physics.optics] 2025


[5] T. Flint et al., SoftwareX 32, 102419, 2025


[6] T. F. Flint et al. SoftwareX, 21, 101299, 2023


[7] I. Bunaziv et al., J. Laser Appl. 36 (3), 2024


[8] R. Cunningham et al. Science 63 (6429), 849-852, 2019


[9] F. Fetzer et al., Opt. Lasers Eng 108, 68-77, 2018


*Ćosić, P.1 Rodriguez, S.1


, Parivendhan, G.1 , Cardiff, P.1


Ivanković, A.¹, Bunaziv, I.2 O’Toole, P.3 D.4


, Flint, T.4 , Allegre, O.4 Ren, Y.5


University College Dublin1 SINTEF2


University of Manchester4 UKAEA5


,


, Universität Stuttgart3 ,


,


, ,


, Mativenga, P.4


, Engelberg, &


,


sean.roche-watson@manchester.ac.uk www.manchester.ac.uk


Sean Roche- Watson is a PhD researcher in laser- based advanced manufacturing at the University of Manchester.


LASER USER 119 MARCH 2026 | 27


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