The use of polymers (or plastics) has contributed to significant weight and cost reductions in many fields, and has reduced environmental impact by enhancing recyclability. Most of the time, it is impossible to produce a part made of a single piece of material with no seams. Joining is required and laser welding of polymers has become a strong competitor of conventional welding techniques. The EU funded project 'Extending the process limits of laser polymer welding with high-brilliance beam sources' (POLYBRIGHT) advanced the current state of the art. Researchers developed novel laser concepts at mid-infrared (IR) wavelengths adapted to the absorption properties of plastic polymers. They increased the laser power through combinations of several diode lasers, and developed a near-IR source and a laser specifically for polymers without additives. Innovative beam-shaping optics modified the intensity of the laser sources for improved welding parameters. Investigators also broadened the range of materials compatible with the technology through development of wavelength-adapted polymers and additives. In fact, one of the biggest challenges — welding of white components such as wash tubs — was achieved with POLYBRIGHT technology. Improvements in process performance, including enhanced thermal management technology and high-speed scanning, together with flexible reconfigurable assembly machines will enable high productivity and reliability at lower costs. Three different prototype machine concepts were developed to combine the new high-brilliance laser sources, optics and high-speed scanning technologies. They were targeted to meet industrial demands of European partner companies in the automotive, white goods and medical device industrial sectors. The prototypes performed well in terms of productivity, quality, cycle time and process repeatability. All tests validated the competitiveness of laser welding of polymers with established welding techniques. POLYBRIGHT's website showcases successes with documentation, newsletters and videos. Project advances overcome the barriers of quality and speed that up to now inhibited implementation of laser welding of polymers. This opens new markets for laser systems and places the EU in a competitive position on the global stage.
Laser welding, polymers, welding technology, laser polymer welding, high-brilliance beam sources, mid-infrared, diode lasers, beam-shaping optics, thermal management technology, high-speed scanning