Single mode fiber laser beam welding with superposed beam oscillation

Multi-kilowatt single mode fiber lasers and highly dynamic scanner optics offer new opportunities for laser material processing. This study seizes the idea of superposed high-frequency beam oscillation, which is known as an effective welding strategy from electron beam welding. The objective of the present work is to develop a model for the prediction of oscillation welding results, based on theoretical considerations and a design of experiments welding series. With this model on hand, the minimum frequency for sound welding with superposed beam oscillation can be concluded. Further a novel method to determine the frequency limit of a scanner system is introduced. This method bases on applying a CHIRP signal (time proportional frequency modulation) to the mirrors of the scanner and the conduction of marking tests, which are subsequently analyzed microscopically.