Local heating with laser radiation
To reduce the energy consumption of the heating processes or to protect temperature-sensitive areas of the workpiece, the heating needs to be restricted to a limited component area. Depending on the application, we analyze the process requirements and develop tailor-made solutions, often consisting of a combination of different types of heat sources. We have accumulated expertise in resistance heating (conduction heat), induction and local laser radiation. Our developments culminate in a special machine or a customer-specific integration module.
Hybrid heating process with zone-based temperature control
The input laser power must be precisely controlled for workpieces with variable geometry or anisotropic material properties, such as fiber composite organo sheets with different thicknesses. This time-limited, localized heating of the component can be achieved much better with the laser than with other heating methods. A position-dependent energy input can be generated on the workpiece surface with hybrid solutions consisting of large-area and locally varying surface heating elements. This allows the desired temperature profile to be adjusted in real time. If required, we use laser sources with different beam guidance and shaping, such as fixed optics, galvanometer scanners or free-form optics, to implement customized solutions. We can implement zone-based temperature control with temperature accuracies of a few degrees Celsius by integrating a thermography module in conjunction with our process control system.
Drying coatings on battery electrodes
Drying coated battery electrodes is the most energy-intensive process step in the lithium-ion battery production chain. Conventional drying solutions that rely on hot gas or infrared radiation are very energy inefficient and can hardly be controlled in terms of time and space. The reason for this lies in process fluctuations during the continuous coating process, which result in varying coating thicknesses and, therefore, heterogeneous drying boundary conditions. This can be remedied by measuring the coating thickness locally and controlling the energy input. We have developed an algorithm that can determine the coating thickness during the continuous drying process. Along with a VCSEL laser module (Vertical-Cavity Surface-Emitting Laser), we have integrated this algorithm into a roll-to-roll (R2R) system. Other drying applications in the field of thin film coating or printing technology can also be adapted.
Fraunhofer Institute for Production Technology IPT