The usage of pulse bursts allows increasing the throughput, which still represents a key factor for machining with ultra-short pulsed lasers. The influence of the number of pulses within a burst on the specific removal rate is investigated for copper and stainless steel. Furthermore, calorimetric measurements were performed to estimate the residual energy coefficient as well as the absorptance of machined surfaces for copper to explain the reduced specific removal rate for a 2-pulse burst and the similar or even higher rate for a 3-pulse burst compared to single pulse ablation. Based on the measurements, a description of the process using single pulses and pulse bursts with up to three pulses is presented.
About the authors
Beat Jäggi received his Bachelor in Mechanical Engineering as well as Master in Engineering from the Bern University of Applied Sciences (BUAS) in Burgdorf, Switzerland. Since 2010, he has been working in the field of laser micromachining using ultra-short pulses. First as a project engineer at BUAS and since 2017, he has been leading the application laboratory of the Lasea Switzerland SA in Biel/Bienne, Switzerland. His current research interests focus on the strategy and process optimization for applications with ultra-short pulsed lasers.
Daniel J. Förster graduated in physics and mathematics at the University of Stuttgart in 2013. He is a research scientist at the Institut für Strahlwerkzeuge (IFSW, Stuttgart Laser Technologies) at the University of Stuttgart and is currently working on his PhD thesis. His research interests focus on fundamentals of laser-matter interaction, especially absorption mechanisms and energy transfer processes during laser micromachining.
Rudolf Weber received his PhD on X-ray emission from laser-produced plasma in 1988 at the Institute of Applied Physics (IAP) of the University of Bern. After a few years at the IAP, heading the ‘Diode-pumped solid-state lasers’ and the ‘Laser materials processing’ groups, he then managed several engineering companies in the field of laser source and application development. Since 2008, he has been the head of the materials processing department of the IFSW of the University of Stuttgart.
Beat Neuenschwander studied physics at the University of Bern and received in 1996 his PhD at the Institute of Applied Physics. Since 2000, he has been at the Bern University of Applied Sciences where he established the laboratory for laser micromachining and is leading the laser surface engineering research group at the institute for Applied Laser, Photonics and Surface Technologies (ALPS). He is a lecturer in physics and applied laser technology, was a member of CTI, is currently expert for Innosuisse, and is head of the optics section of the Swiss Society for Optics and Microscopy (SSOM).
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