Monitoring of laser beam welding by a non-intrusive optical sensor system using photodiodes
2015 (English)In: Proceedings of JOM 18 International conference on joining materials, Helsingör, Danmark, april 26-29 2015, JOM-institute , 2015, 1-14 p.Conference paper (Refereed)
Monitoring and control of automated laser beam welding is necessary in order to increase weld quality and to optimise the process. This paper presents an evaluation of an optic monitoring system using photodiodes, integrated coaxial into the laser welding tool to monitor the optical electromagnetic emissions from the process. Three photodiodes are used, one for the visual spectra, one for the reflected laser light and one for the infrared spectra.A survey of previous research regarding monitoring of welding using photodiodes have been conducted, it indicated the need for development of a high bandwidth monitoring system able to capture the fast dynamic events of the welding process. Based on this a monitoring system was developed and the frequency components of the monitored signals was analysed. Welding experiments, using a 1 μm YAG laser on nickel-based alloy sheet metal of different thicknesses, has also been conducted in order to evaluate the correlation between monitored signals and change of parameters effecting the weld quality. Laser power and laser focus was changed during the experiments.I was shown that a bandwidth of 30 kHz for the monitoring system would be sufficient to capture the interesting components of the signals from the photodiodes. A clear correlation between signal level from the sensor monitoring the infrared spectra and weld penetration was found and also a correlation between reflected laser light and laser beam focus. High intensity peaks was found in the signal from the sensor monitoring the visual spectra. It is assumed, but not confirmed, that they show the formation plasma in the key hole.
Place, publisher, year, edition, pages
JOM-institute , 2015. 1-14 p.
JOM, ISSN 2246-0160
Photodiode, Process Monitoring, Laser Beam Welding
Manufacturing, Surface and Joining Technology
Research subject Production Technology; ENGINEERING, Manufacturing and materials engineering
IdentifiersURN: urn:nbn:se:hv:diva-8617OAI: oai:DiVA.org:hv-8617DiVA: diva2:866664
JOM 18 International conference on joining materials, Helsingör, Danmark, april 26-29 2015