Analysis of characteristics of molten pool using cast shadow during high-power disk laser welding

Quality assessment in laser welding: a critical review

“…Therefore, the studies found in literature focus on the improvement of identification accuracy and the development of intelligent algorithms for the correlation of signals with weld geometry and defects. The last argument has also been demonstrated by the authors in [36].…”

“…Finally, it was proven through experiments that the method could automatically measure and monitor the weld pool surface within an acceptable error range. Zhang and Cao [36] also developed a vision system with an auxiliary laser light source in order to acquire the images of molten pool for quality assessment. The novelty of the paper and the difference from the previous studies are noticed in the fact that the authors have analyzed the characteristics of the casting shadow of molten pool instead of having analyzed the characteristics of the molten pool itself.…”

“…However, there is a lack of temperature feedback which excludes valuable information for the physical phenomena that occur during laser welding. Furthermore, the accuracy of the keyhole geometrical parameters captured by a visual sensor is highly dependent on the implemented image processing technique [36]. Thus, the capabilities of such systems for adequate quality inspection are limited.…”

“…The optical sensors are classified into the literature differently, depending on the writer [36]. A usual classification that is made by several authors is a division into spatially resolved (vision system, e.g., CCD and CMOS cameras), spatially integrated (photodiodes), or spectrally resolved (spectrometers) techniques [53].…”

“…The thermal radiation intensity reflects changes in temperature and can be detected with the use of a pyrometer sensor [36]. The existence of defects or the penetration and width values can be obtained from the variations of the temperature field.…”