Product Code: ICAL07_M301

In-Process Monitoring and Adaptive Control in 100W Fiber Laser Welding
Authors:
Yousuke Kawahito, Osaka University; Ibaraki Japan
Masaharu Kawasaki, Osaka unversity; Ibaraki Japan
Seiji Katayama, Osaka unversity; Ibaraki Japan
Presented at ICALEO 2007

A fiber laser is easily applied for micro welding owing to the excellent beam quality. Moreover, hand, a fiber laser is expected to be a promising heat source for adaptive control since the peak power is variable within sub-micro-second period. The objective of the research was to develop a new laser system with in-process monitoring and adaptive control for the stable production of sound welds in thin sheets. The bead-onplate welding of 0.1 mm-thick stainless steels was performed with a 75 W fiber laser beam of 1,090 nm wavelength. The stability of bead widths of laser welds made with or without monitoring and adaptive control was investigated in welding the sheet with or without heat exchanger plate. It was revealed that the heat radiation signal was sensitive to the increase in the bead width according to the change from heat transfer process to heat-insulated process. Moreover, the peak power was adaptively controlled in the minimum 50 ms-short period in order to produce stable weld bead width regardless of the existence or absence of the heat transfer plate. Consequently, it was confirmed that the fiber laser was an excellent oscillator for laser micro welding as well as for adaptive control.