Product Code: ICA10_1105

Simultaneous Sub Second Laser Welding of Polymers with Diffractive Optics
Authors:
Petri Laakso, VTT Technical Research Center of Finland; Lappeenranta Finland
Saara Ruotsalainen, VTT Technical Research Center of Finland; Lappeenranta Finland
Tuomas Purtonen, Lappeenranta University of Technology; Lappeenranta Finland
Hannu Minkkinen, VTT Technical Research Center of Finland; Tampere Finland
Veli Kujanpää, VTT Technical Research Center of Finland / Lappeenranta University of Technology; Lappeenranta Finland
Antti Salminen, VTT Technical Research Center of Finland / Lappeenranta University of Technology; Tampere Finland
Presented at ICALEO 2010

The paper presents a novel method for simultaneous transmission welding of polymers using a high power multimode fiber laser. The method utilizes a diffractive optical element which shapes the focused laser beam into the desired shape. This kind of optical device enables the use of high power multimode fiber laser which again gives a possibility to use sub-second welding times.

Weld quality was assessed in terms of strength (pull test) and visual outlook. The diffractive optics provide an even power distribution and only small part is lost on the zero order.

Design of diffractive element gives flexibility with the weld shapes and sizes but of course these parameters cannot be modified after production of the element. Using the optics would be more advantageous if multiple parts could be welded at one shot because the part changing time will be a lot longer than the welding time. Results show good weld quality, superior welding speed and good weld strength compared to quasi-simultaneous laser welding of the same material.