FIBER LASER WELDING OF PLASTICS USING A SOLID HEAT SINK TRANSPARENT TO THE LASER BEAM TO PREVENT THERMAL DAMAGE

摘要

This paper deals with the fiber laser welding of overlapped engineering plastic sheets, using a solid heat sink transparent to the laser beam to prevent thermal damage. A fiber laser whose wavelength is 1.9 μm is used for the welding. It is hard to join transparent engineering plastics not using any laser-absorbing pigments with ordinary laser welding. So this novel laser welding procedure, which prevents thermal damage to the surface of the plastic, was proposed. A solid heat sink is placed in contact with the irradiated polymer sheet, helping to prevent thermal damage of the film surface. Thus, the proposed fiber laser welding system is successful in welding plastic sheets which are difficult to weld with CO_2 laser.