Sven Thomas, Sem Massa, Max Rettenmeier, Steffen Wagenmann, Tim Hesse, Nicolai Speker, Christian Hagenlocher, Thomas Graf
Burr formation in laser cutting reduces the quality of the cut and causes the need for extra processing of parts. In this paper in-situ high-speed imaging has been used to gain insights into the impact of the melt dynamics in the cutting kerf on the formation of burr during laser cutting of metal. The images captured both, the melt dynamics in the kerf and the adhesion of the melt to the lower edge of the sheet. The results show that the formation of burr is due to the detachment of melt droplets from the cutting front to the edge of the cutting kerf, which then adhere to the rear side of the sheet. In addition, the adhesion of molten material at the lower side of the cutting front and the subsequent flow of the molten material along the lower edges of the cutting kerf also leads to formation of burr.
Keywords: laser cutting; high-speed imaging; melt dynamics; burr formation; cut kerf
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Bertella L., Trivisonno A., Agostini C., Gandolfi D., Pacher M., Moretti G., Vanin M.
Precision in manufacturing has become essential in today’s competitive market, necessitating the minimization of all sources of inaccuracies. In the laser cutting process, the inherently thermal nature introduces significant heat to the workpiece, causing thermal expansion and dimensional errors in the absence of compensating strategies. These issues are particularly pronounced in aluminium tube workpieces due to their high thermal conductivity, large expansion coefficient, and extended axial dimensions of the raw material, which amplify thermal expansion effects. This study addresses these challenges by developing a real-time-capable predictive dynamic model. The model correlates commanded laser power with average heat-induced temperature increase, enabling precise, workpiece-specific thermal expansion estimation while maintaining computational efficiency. Calibrated and validated on an industrial laser tube machine, the proposed strategy achieves an average error reduction up to 75%, significantly improving dimensional accuracy and offering a robust solution for high-precision laser-based manufacturing.
Keywords: Laser cutting; Thermal expansion; Thermal errors; Predictive dynamic model
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Sofia Guerra, Leonardo Caprio, Matteo Pacher, Davide Gandolfi, Mattia Vanin, Mara Tanelli, Sergio M. Savaresi, Barbara Previtali
To meet stringent requirements in terms of productivity and efficiency, the industry is shifting towards machine tools with sensors and auto-tuning capabilities enabled by Artificial Intelligence (AI) algorithms. Accordingly, in laser cutting the coaxial monitoring of the molten pool provides relevant information that can be interpreted by means of Machine Learning (ML) approaches to enable real-time velocity-based feedback control. In the present research, a holistic control architecture was thus developed and validated on an industrial case-study to demonstrate its applicability. Targeting iso-quality conditions, experiments on sample geometries on 5 mm thick stainless steel allowed to showcase an increase in productivity whilst avoiding critical defects such as cut dominated by plasma formation or loss of cut. The results obtained may be extended to a wide range of materials and sheet thicknesses demonstrating the generalized applicability of the technological framework.
Keywords: Laser cutting; Machine learning; Process control
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Investigating the Effect of Different Axial Oscillation Patterns on Laser Fusion Cutting Process
Busatto M., Meyer J., Caprio L., Gandolfi D., Herwig P., Vanin M., Previtali B.
Latest research on laser cutting has revealed significant improvements in process productivity and cut quality through the applications of dynamic beam shaping techniques. The present work aims to study the effect of axial beam oscillations (along Z-axis) on laser fusion cutting process through analytical modelling and experimental investigations. While existing literature has primarily focused on dynamic beam shaping employing harmonic oscillations, this study explores the impact of various oscillation waveforms, including sinusoidal, triangular, square, ramp-up, and ramp-down patterns. Initially, an analytical model was developed to evaluate the laser intensity distribution within the process zone for different oscillation patterns. Furthermore, the effect of axial oscillations, superimposed on the cutting direction, was experimentally investigated using 20 mm thick AISI304 stainless steel. Experimental results demonstrate notable improvements in process performance through axial oscillation, either by reducing burr defects at the same processing speed or by increasing productivity while maintaining equivalent part quality.
Keywords: Laser cutting, Laser beam shaping, Laser beam axial oscillations, Waveforms
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Laser cutting of glass ribbon via melting at the draw
Anatoli A. Abramov, Christopher Chilson, Mariia A. Lapina, Artemiy A. Shamkin, Boris N. Tsvetkov
In continuous glass manufacturing processes, such as fusion draw, it is essential to cut a glass ribbon into sheets without disruption of the glass flow. This is typically achieved through the use of mechanical or laser cutting apparatuses, which enable the separation process by cross-ribbon scoring followed by bend breaking. This study presents a method for on-draw cutting of hot glass ribbon through localized melting using an infra-red laser beam. Our findings demonstrate that cutting the ribbon, which is already formed but maintains temperature within the annealing range, allows full body ribbon separation through glass melting without generating excessive residual stress. Additionally, this laser-induced process results in the formation of a rounded edge, which might eliminate the need for further finishing in certain applications. An experimental platform, comprising the glass draw, and laser system developed along with a theoretical model of the process are presented.
Keywords: laser melting; glass; fusion draw
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Ulrich, Stefan; Tarkan, Alper; Mercon, Hüseyin; Steinert, Michael; Reinlein, Claudia
The article demonstrates the potential of axial dynamic beam shaping in laser fusion cutting, as evidenced by cutting tests. Although lateral beam shaping is already well-established, axial dynamic beam shaping has been demonstrated to enable faster process optimization by reducing the number of degrees of freedom at laser powers up to 20 kW. The technology utilizes high-frequency beam oscillations along the beam propagation to regulate the energy distribution within the material. Tests were conducted on 10 mm-thick stainless steel using laser powers ranging from 8 kW to 20 kW. The results demonstrated that axial dynamic beam shaping increased the cutting speed by up to 82% and reduced the burr height by a factor of 11. This suggests that axial dynamic beam shaping improves energy distribution in the component, reduces the risk of burr formation and optimizes cutting quality while increasing productivity. In conclusion, an explanatory approach has been devised to elucidate the impact of axial dynamic beam shaping on the cutting process.
Keywords: axial dynamic beam shaping; laser cutting, stainless steel
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