Modeling and analysis of laser drying processes for wet-coated battery electrodes
Teng Chen, Orçun Atasever, Jan-Hendrik Koch, Florian Hüsing, Christian Brecher
The drying of lithium-ion battery electrodes is one of the most energy- and cost-intensive processes within the battery production chain. Recently, laser drying has emerged as a promising energy-efficient alternative to the conventional convective and infrared drying methods due to its direct energy input, high energy density and superior controllability. However, the underlying process mechanism remain incompletely understood, and its full potential has yet to be reached. In this work, a numerical process model was developed to simulate the changes in evaporation rates, film thickness as well as the film temperatures, while also estimating the process duration and energy consumption for both laser and convective drying methods. Comparative analysis was made between two drying methods in terms of their process durations and energy consumptions. Furthermore, the process disturbance in the coating and drying processes was addressed, and a concept of model-based process control was developed.
Keywords: laser drying; lithium ion battery; numerical simulation; process control
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Influence of the beam diameter on the resistance of laser guards to green laser radiation
Matthias Lista, Uqba Aftab Alam, Rico Bühring, Moritz Beck, Hans-Joachim Krauß
To protect operators from laser radiation, laser machines must have a protective enclosure. The requirements for laser protective shielding are defined in the current standard EN 60825-4. According to this, extensive case-related laser stability tests must be carried out on the protective material. These case-related tests make it difficult to compare and select suitable materials and thus considerably increase the effort for manufacturers. Therefore, the SALSA project is taking a different approach: The influence of the beam diameter and the irradiance on the laser resistance of common protection materials is systematically investigated and the relationships found are expressed in simple mathematical formulas. This should enable manufacturers to use exemplary laser stability measurements to extrapolate service lifetimes for any operating conditions. The study describes the relationships found using green laser radiation, since laser radiation in the visible wavelength range is currently of particular importance for applications in e-mobility.
Keywords: laser safety; machine safety; laser guards; laser resistance; beam diameter dependence
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Andreas Krämer, Timon Ahlers, Ronald Pordzik, Tim Radel
During laser deep penetration welding, disturbances of the nominal process can lead to seam imperfections. Due to their possibly impairing characteristics on the mechanical properties of the seam, it is of high interest to reliably detect these defects. This can be achieved by means of sensor based inline process monitoring. While the sensor data can be employed to identify the defect location and perform post process repair work, it can also build the foundation to reweld the detected seam segments inline to enhance the seam quality and possibly eliminate necessary post process work. This study demonstrates an approach to detect provoked process anomalies during laser deep penetration welding of hidden T-joints in line and use a LabVIEW based control algorithm to utilize the scanning capabilities of the welding optic to reweld the defected seam area inline.
Keywords: multisensory process monitoring, rewelding, process control
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Jan-Niklas Schneider, Leon Gorißen, Thomas Kaster, Christian Hinke
The integration of galvanometer scanners and robotic manipulators in laser material processing poses challenges due to their independent hardware and software architectures. Synchronizing these systems requires precise coordination of robotic motion and galvanometer scanner control, particularly for complex path planning tasks. This paper introduces a framework that leverages the Robot Operating System (ROS) and its open-source, modular, and widely-adopted capabilities in robotics to unify the control of robot and galvanometer scanner. A service-oriented, publish-subscribe wrapper and a ros2_control hardware interface are implemented to manage scanner mirror positions and robotic joint movements, ensuring accurate laser beam positioning and process consistency. Future research may explore additional factors such as dynamic power control, deep learning, and vision-based system integration. This scalable and flexible approach demonstrates the potential of ROS to drive innovations in laser material processing.
Keywords: ROS (Robot Operating System); Galvanometer Scanners; Path Planning; Laser Material Processing; Process Control;
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Definition of requirements for robust seam-tracking in robotic laser welding applications
Matteo Moscatelli, Serge André Dib, Cristiano Raffaldi, Mara Tanelli, Ali Gökhan Demir
The increasing adoption of robotic laser welding highlights the need for robust seam-tracking systems to ensure precision and adaptability. Current methods struggle with fixturing errors, part-to-part variations, thermal deformation and the need for precise alignment of the laser beam, especially in three-dimensional welding scenarios. Laser welding is particularly sensitive to variations in joint morphology and material reflectivity, requiring advanced solutions to maintain high welding quality. Spatial beam shaping techniques, based on beam oscillation or “wobbling”, partially mitigate these issues by accommodating variable joint gaps and high-reflectivity materials. However, solutions, capable of real-time trajectory planning and adaptive process control, are essential to meet the requirements of this technology. This work presents a comprehensive analysis of the technological and computational requirements for seam-tracking operations, providing a foundation for developing systems capable of operating at high welding velocities, while ensuring quality and minimizing rework, paving the way for a more-effective implementation in smart-manufacturing.
Keywords: Robotic Laser Welding; Seam-Tracking; Spatial Beam Shaping; Real-Time Process Monitoring
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Improving Remanufacturing with Cobots: Sensor-Enhanced Path Planning for Automated Laser Cleaning
Thomas Kaster, Jan-Niklas Schneider, Leon Gorissen, Christian Hinke
This paper presents a novel conceptual two-step approach for automated laser cleaning in the remanufacturing process using collaborative robots (cobots) and sensor-enhanced path planning. Remanufacturing is a key enabler of the circular economy, but current processes, especially cleaning, remain labor-intensive and inefficient in the context of individual and small series production. The integration of flexible robotic systems with advanced sensing and control architectures enables precise and adaptable surface treatment. Our system leverages the Robot Operating System (ROS) for modular, real-time integration of laser control, sensor fusion, and motion planning. The proposed method significantly reduces manual involvement, increases repeatability, and opens up new possibilities for sustainable and intelligent manufacturing, making the approach accessible to small- and medium-sized enterprises (SMEs) with limited automation capacity.
Keywords: Remanufacturing; Circular Economy; Robotics; Laser; Laser Cleaning
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OCT for Controlled and Precise Robotic Arc Welding and Tactile Laser Welding and Brazing
Nataliya Deyneka Dupriez
The capability of OCT technology for real-time seam tracking and weld bead quality evaluation was examined in robot-guided automated GMAW and tactile laser welding and brazing of automotive parts made of bare steel, coated steel and aluminum with different joint types at different welding speeds. The permissible gap size and gap compensation were investigated for both automated conventional and tactile laser welding. During tactile laser welding and brazing, the filler wire speed and laser power were varied. Satisfactory results were achieved: The industry-proven, standardized OCT functions and fieldbus communication enabled accurate and consistent seam tracking, gap bridging and online quality monitoring of the seam topography of the tested materials during processing with variable welding or brazing parameters. Thanks to the flexibility, insensitivity to environmental conditions and very high accuracy of the OCT system, the joining processes could be precisely controlled.
Keywords: Optical coherence tomography; tactile laser welding; laser brazing; arc welding; seam tracking; seam quality monitoring; high accuracy; consistency