A model for predicting the borehole geometry for laser drilling is presented based on the calculation of a surface of constant absorbed fluence. It is applicable to helical drilling of through-holes with ultrashort laser pulses. The threshold fluence describing the borehole surface is fitted for best agreement with experimental data in the form of cross-sections of through-holes of different shapes and sizes in stainless steel samples. The fitted value is similar to ablation threshold fluence values reported for laser ablation models.
About the author
Alexander Kroschel studied Mechanical Engineering at the Ilmenau University of Technology, Germany. Since 2016, he is a doctoral student at the University of Stuttgart, Germany, and Robert Bosch GmbH. His research topic is on laser drilling with ultrashort laser pulses.
The authors wish to thank Satoshi Oyama from Canon Europa N.V., Yukihiro Inoue from Canon Inc., and Matthias Reuter from Nexlase GmbH for getting the possibility to use a five-axis scan system from Canon Inc. to conduct the validation experiments. They would also like to thank Franziska Bauer and Adina Kanstinger for their experimental support.
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