Basic study of photodiode signals from laser welding emissions

• Photodiodes are commonly used to monitor laser welding as a cheap, rugged, online method to get an indication of changes in the process, particularly the occurrence of defects. However, the correlations between the signal characteristics and the process are usually empirical and not fully understood. In this basic study we try to obtain a better understanding of the generation of the signals from the laser welding process. By synchronising high speed imaging with photodiode signals in three wavelength spectra, we attempt to identify the contributions from different geometrical domains and temporal events, particularly from the weld pool surface, the keyhole opening and the escaping metal vapour flow. It is particularly valuable to study dynamic behaviour during pulsed laser welding. A quantitative estimation is difficult, but , with the help of high speed photography and modelling, clear correlations between different dynamic events and signal changes can be identified.

Subject headings

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Bearbetnings-, yt- och fogningsteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Manufacturing, Surface and Joining Technology (hsv//eng)

Keyword

Manufacturing Systems Engineering

Produktionsutveckling

Publication and Content Type

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