Analysis of laser remote fusion cutting based on a mathematical model

• Published in: Journal of applied physics 2013-12, Vol.114 (23)
• Main Authors: Matti, R. S., Ilar, T., Kaplan, A. F. H.
• Format: Article
• Language: English
• Subjects: ABLATION; ABSORPTIVITY; Applied physics; Beam interactions; BEAMS; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CUTTING; Cutting speed; Domains; Empirical analysis; ENERGY BALANCE; EVAPORATION; Fiber lasers; FLEXIBILITY; Fusion cutting; HEAT FLUX; HEAT LOSSES; Inclination; Laser ablation; Laser beam welding; LASERS; Low speed; Manufacturing Systems Engineering; MASS BALANCE; Mathematical analysis; MATHEMATICAL MODELS; MELTING; POWER DENSITY; Produktionsutveckling; Statistical analysis; STEADY-STATE CONDITIONS; Three dimensional models; THREE-DIMENSIONAL CALCULATIONS; Vaporization; Waviness; WELDING
• ISSN: 0021-8979; 1089-7550; 1089-7550
• DOI: 10.1063/1.4849895

Laser remote fusion cutting is analyzed by the aid of a semi-analytical mathematical model of the processing front. By local calculation of the energy balance between the absorbed laser beam and the heat losses, the three-dimensional vaporization front can be calculated. Based on an empirical model for the melt flow field, from a mass balance, the melt film and the melting front can be derived, however only in a simplified manner and for quasi-steady state conditions. Front waviness and multiple reflections are not modelled. The model enables to compare the similarities, differences, and limits between laser remote fusion cutting, laser remote ablation cutting, and even laser keyhole welding. In contrast to the upper part of the vaporization front, the major part only slightly varies with respect to heat flux, laser power density, absorptivity, and angle of front inclination. Statistical analysis shows that for high cutting speed, the domains of high laser power density contribute much more to the formation of the front than for low speed. The semi-analytical modelling approach offers flexibility to simplify part of the process physics while, for example, sophisticated modelling of the complex focused fibre-guided laser beam is taken into account to enable deeper analysis of the beam interaction. Mechanisms like recast layer generation, absorptivity at a wavy processing front, and melt film formation are studied too.