Why Color Matters—Proposing a Quantitative Stability Criterion for Laser Beam Processing of Metals Based on Their Fundamental Optical Properties
Kohl S, Kaufmann F, Schmidt M (2022)
Publication Type: Journal article
Publication year: 2022
Journal
Book Volume: 12
Pages Range: 1118
Issue: 7
DOI: 10.3390/met12071118
Abstract
With its excellent automation capability and localized energy input enabling precise, reproducible welds, laser beam welding represents a preferred industrial joining technology. Electro-mobility drastically increases the need for defect-free and automatable copper joining technologies. However, copper welds that are produced with state-of-the-art infrared lasers often suffer from spattering and porosity. Recent publications show distinct improvements using novel beam sources at visible wavelengths, attributing them to increased absorptivity. Nevertheless, this cannot fully explain the steadier process behavior. This wavelength-dependent process stability has not yet been investigated sufficiently. Therefore, we have developed a predictive material-dependent criterion indicating process stability based on the example of copper heat-conduction spot welding. For this purpose, we combined energy balances with thermo-physical material properties, taking into account the wavelength and temperature dependence of the optical properties. This paper presents the key mechanism that we identified as decisive for process stability. The criterion revealed that X-points (unique, material-specific wavelengths) represent critical stability indicators. Our calculations agree very well with experimental results on copper, steel and aluminum using two different wavelengths and demonstrate the decisive, material-dependent wavelength impact on process stability. This knowledge will help guide manufacturers and users to choose and develop beam sources that are tailored to the material being processed.
Authors with CRIS profile
Stefanie Kohl
Lehrstuhl für Photonische Technologien
Florian Kaufmann
Michael Schmidt Lehrstuhl für Photonische Technologien
Michael Schmidt Lehrstuhl für Photonische Technologien
Involved external institutions
Germany (DE)How to cite
APA:
Kohl, S., Kaufmann, F., & Schmidt, M. (2022). Why Color Matters—Proposing a Quantitative Stability Criterion for Laser Beam Processing of Metals Based on Their Fundamental Optical Properties. Metals, 12, 1118. https://dx.doi.org/10.3390/met12071118
MLA:
Kohl, Stefanie, Florian Kaufmann, and Michael Schmidt. "Why Color Matters—Proposing a Quantitative Stability Criterion for Laser Beam Processing of Metals Based on Their Fundamental Optical Properties." Metals 12 (2022): 1118.
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