Macro: Cutting 1
10:00am - 10:30am
Invited Talk: Laser cutting - past and present
Laser Expertise, United Kingdom
Laser Cutting is over 50 years old! It has passed though its childhood, difficult teenage years, and early adulthood, to become the mature technology we know today.
Dr John Powell has worked in the subject since the early 1980’s and will present a talk which describes some of the early difficulties of the process and how they were overcome.
The talk will combine a general history of laser cutting with personal anecdotes - including a few comments on laser cutting in the days before laser safety was invented (Luckily, the plastic pipes exploded before the flames reached the hydrogen bottle).
10:30am - 10:45am
Fundamental characteristics of fiber laser beam sawing of 10 mm thick stainless steel
Fraunhofer-Institut für Werkstoff- und Strahltechnik IWS Dresden, Germany
AISI 304 stainless steel plates of 10 mm thickness were separated 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.
10:45am - 11:00am
Monitoring of the melt pool for fiber laser cutting using a high-speed camera
1University of Applied Sciences Aschaffenburg; 2University Bayreuth
We demonstrate an in-situ and coaxial monitoring system based on a high-speed camera with a spectral response in the visible range, which is designed to be integrated into a cutting head between the collimator and processing lens. The thermal radiation from the melt pool is measured in the visible spectral range, without external illumination, spatially and temporally resolved from the top view. The dependencies of the laser power and feed rate on the spectral and geometric information captured from the images of the melt pool in the cut kerf are evaluated. In addition, we developed and show an algorithm to detect incomplete cuts caused by laser power and feed rate from the captured images.