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Session Chair: Dr. Klaus Schricker, Technische Universität Ilmenau, Germany
Location:Room 4 ICM
10:00am - 10:15am
Corrosion resistant blackmarking via numerical modeling and simulation
Urs Eppelt, Daniel Seitz, Jörg Ziegler
Coherent Munich, Germany
Classical Laser Blackmarking with USP laser sources is a well-established process that is commercially available nowadays since a few years. This is especially true for its wide use on stainless steel supplies of the medical industry. Surprisingly, other industries (like household and consumer products industries) have even higher requirements on wear behavior (like corrosion resistance) than the medical industry with its strict approval procedures.
With the help of mathematical modeling and numerical simulation we wanted to understand the in-depth reasons for the limitations of classical blackmarking and develop a new laser marking process that could also fulfill the demands for acid resistance on products like white goods, sanitary fittings or automotive accessories which have not yet been opened up for this kind of laser process. We describe our success in modeling and simulation as well as process development in that field which is then evaluated by corrosion testing procedures.
10:15am - 10:30am
Estimating heat accumulation upon ultrafast laser irradiation
Liliana Cangueiro1, Thomas Kiedrowski2, Nikolaï Schroeder3, David Bruneel1, Andrés Lasagni3, J.A. Ramos-de-Campos1
1LASEA, Belgium; 2Robert Bosch GmbH; 3Institut für Fertigungstechnik Technische, Universität Dresden
Ultrafast lasers micromachining results depend both on the processing parameters and the material properties. The obtained thermal effects are negligible if a good combination of processing parameters is chosen. However, optimizing the processing parameters leading to the required surface quality on a given material can be quite complex and time consuming. Within the framework of the European project LAMpAS, we developed a model to estimate the heat accumulation on a surface as a function of the laser fluence, scanning speed and line pitch. The simulation results were correlated with experimental ones on different materials. The predictions of the model allow evaluating the heat distribution on the surface, as well as optimizing the ultrafast laser micromachining strategy yielding negligible thermal damage.
10:30am - 10:45am
Experimental setup for determination of absorption coefficient of laser radiation in molten metals as a function of temperature and angle
Tjorben Bokelmann1, Marius Lammers1, Jörg Hermsdorf1, Sobhan Emadmostoufi2, Oleg Mokrov2, Rahul Sharma2, Uwe Reisgen2, Stefan Kaierle1
1Laser Zentrum Hannover e.V., Germany; 2Welding and Joining Institute, RWTH Aachen University, Germany
For the process development of laser assisted double wire welding with nontransferred arc (LDNA), the simulation of the molten pool and its interaction with the laser radiation is of great importance. Therefore, an experimental setup for the determination of the temperature and angle dependent absorption coefficient of laser radiation in molten metals such as stainless steel and aluminum will be presented. A Yb:YAG disc laser with 1030 nm and a 940-1020 nm diode laser are used as laser beam sources. The stationary molten metal is inductively warmed and superheated by the laser beam with approximately 300-1000 W, whose radiation profile is shaped by homogenizing optics and ensures equal intensity when the angle is adjusted.