Fundamental characteristics of fiber laser beam sawing of 10 mm thick stainless steel

AISI 304 stainless steel plates of 10 mm thickness were sectioned by fibre laser beam sawing trials. The applied sawing technique as a new variant of laser cutting with an oscillating beam relies on periodical changes of the focusing length of the optical setup by integrated mirrors with adjustable curvature radius. As a result, the focal plane position can be forced to oscillate with a frequency of up to 4800 Hz and amplitudes up to 6 mm. The resulting temporally averaged beam profile is characterized by a nearly constant beam diameter over the whole spatial oscillation range. Variations of oscillation frequency, amplitude and nominal focal layer position were performed to get first insights into the effect mechanisms of fibre laser beam sawing. It is found that the cut kerf geometry can be adjusted to improve cutting gas flow characteristics and melt removal.