Laser welding of plastic materials has a large field of applications in the
packaging industry provided that it can compete, in quality and productivi
ty, with currently used industrial methods. Welding of white and transparen
t thin films of polypropylene and polyethylene of low and high density at h
igh speeds of 20 m s(-1) using a CO2 laser has been studied experimentally.
The weld process has been characterised by the specific energy required fo
r each thickness, kind of plastic and the resistance of the weld seam. The
influence of the dimensions of the laser beam spot on weld strength has als
o been analysed. (C) 2001 Elsevier Science Ltd. All rights reserved.