As part of a research project, “Absorber systems for laser welding of textiles,” scientists at the Hohenstein Institute are currently working with colleagues from the German Wool Research Institute in Aachen on developing new infrared absorber systems to improve the quality of laser welded seams, both mechanically and visually. This should enable the laser welding of textiles, which is an alternative and promising but still new technique for making seams, to be introduced more widely.
The laser welding of textiles has many advantages compared with traditional stitching. The biggest improvements in product quality can be achieved in the processing of large-scale technical textiles. The seams produced by welding are flat, flexible, completely sealed against liquids and gases and have impressive tensile strength. The normal seam defects can be avoided and the quality of the welding process can be automatically monitored online. These properties are demanded in many technical fields such as medical textiles, protective clothing, textiles for vehicle interiors, furniture manufacture and outdoor products. The new process would minimize the currently very time-consuming testing of the quality of the seams which must be carried out during and after the manufacturing process.
One of the problems inherent in the still relatively new method involving an infrared laser is that only a few textiles, made of thermoplastic fibers, absorb laser radiation in the near-infrared range. This means that, with many textiles, absorbers must be used that are specifically designed to absorb the infrared light. However, these substances can cause discoloring or color changes round the seams. As part of this ongoing research project, new absorber systems are to be developed and systematically studied.
The new formulations need to be easy to use and economical on materials, compatible with the textile material and meet all the preferred requirements as far as possible. Especially on light-colored and transparent textiles, they should result in seams that are perfect visually and mechanically. The variable parameters for laser welding such as temperature, speed and pressure can be adapted to suit the absorbers, which will enable manufacturing companies to use the process directly for their own materials and product range.