Welding of polymers using a 2 μm thulium fiber laser

Absorber-free transmission and butt-welding of different polymers were performed using thulium fiber laser radiation at the wavelength 2 μm. The relations between the laser process conditions and the dimensions and quality of the seam were investigated by means of optical and phase-contrast microscopy. Mechanical properties of the weld joints were studied in tensile strength tests. Laser-welded polyethylene samples revealed a tensile strength of greater than 80% of the bulk material strength. Transmission welding of different polymer combinations featured the formation of different joint classes depending on the spectral properties. The experiments demonstrate new application areas of mid-IR fiber laser sources for materials processing.

► We performed absorber-free transmission and butt-welding of different polymers using mid-IR fiber laser radiation.
► Laser-welded polyethylene samples revealed a tensile strength of greater than 80% of the bulk material strength.
► Transmission welding of polymer combinations showed the formation of different joint classes.
► Experiments demonstrate new application areas of mid-IR fiber laser sources for materials processing.