Most common lasers in polymer welding are CO2-, Nd:YAG- and diode laser. Diode lasers, with a wavelength 800-1000 nm, are most commonly used in polymer laser welding. Laser beam welding can be divided in two different process variants: 1) butt welding and 2) laser transmission welding. Butt welding includes three steps: heating, movement and welding. Connected surfaces are heated close to melting temperature and pressed together. In the laser transmission welding the top polymer part has to be transparent for the laser beam and the bottom polymer part absorbs it. The bottom part warms up and melts by laser beam. The heat conducts from the lower part to the transparent part and melts it when these two parts are pressed together. Advantages of polymer laser welding are e.g. high speed and flexibility, small and narrow welds and hermetic 3 D joints. All most all thermoplastic and elastomers could be welded by laser.
Laser welding of polymer