Drying with diode lasers is a cost-efficient and environmentally friendly alternative to the widely used convective oven drying. With homogeneous area spots, even large surfaces with side lenghts of up to 2 m can be irradiated. In principle, all materials that exhibit sufficient absorption for the laser wavelength can be dried. The laser beam heats only the coating, thus yielding a targeted evaporation of the solvent or even sintering on the workpiece. The spectral range of the laser radiation used is either in the near infrared range (NIR), more precisely between about 900 and 1070 nm, or around 445 nm in the case of blue diodes. Due to the ease of integration into existing machine concepts, fiber-guided high-power diode laser systems of 1-50 kW output power are generally used.
The process advantages provided by diode lasers
- Energy efficiency of diode laser systems (WPE) > 50%.
- Precise energy transfer to the layer to be dried, where almost 100% of the photon energy is absorbed and used for drying. This is also referred to as ‘cold drying’.
- Closed-loop control (temperature versus laser energy).
- Extremely homogeneous spot areas, size adjustable, and for pilot applications with zoom function.
- Energy savings of 25-50% compared to convection dryers.
Diode-laser-based drying in a roll-to-roll process: A better alternative to gas-based convection ovens and high-maintenance infrared lamps
The semiconductor-based direct conversion of mains power into laser radiation functions independently of fossil fuels and also provides pinpoint energy use in the process. Laser drying significantly reduces the space required for the production environment and enables faster process speeds with more energy-efficient process control. In particular for the production of lithium-ion batteries, Laserline diode lasers are ideally suited to drying of the electrode paste (slurry).
Energy and quality turnaround for drying processes
Replacing convective drying with laser drying? In times when highly efficient electrified solutions are sought in the face of gas shortages and rising energy costs, this could become the standard. Diode-laser-based drying processes in roll-to-roll mode, optimized by a revolutionary beam shaping technology, bring excellent throughput rates and results as well as making a significant contribution to gas phase-out and climate protection.