Characteristics of Plasma Emission Signals in Fiber Laser Welding of API Steel (Ⅳ)<br>
- Correlation of Keyhole's Periodic Motion and FFT Analysis Results -

Kim, Jong-Do; Lee, Chang-Je; Suh, Jeong

doi:2013.31.4.28

J Weld Join > Volume 31(4); 2013 > Article

Research Paper

Journal of KWJS 2013;31(4):28-33.
DOI: https://doi.org/10.5781/KWJS.2013.31.4.28 Published online August 31, 2013.

Characteristics of Plasma Emission Signals in Fiber Laser Welding of API Steel (Ⅳ)
- Correlation of Keyhole's Periodic Motion and FFT Analysis Results -

Jong-Do Kim¹, Chang-Je Lee², Jeong Suh³

Correspondence: Jong-Do Kim,
Email: jdkim@hhu.ac.kr

Abstract

The effects of laser welding beam quality is very large. However, not an analysing case was found for the difference on the plasma emission signal during laser welding according to the beam quality. Therefore, in this study, we compared and evaluated penetration and signal change according to the beam quality at the a similar wavelength band by using a fiber laser and Nd:YAG laser. In addition, we took high speed videography in order to make sure that FFT analysis reflects the actual motion period of keyhole and found the period of video analysis and FFT mostly matched. As a result, it is expected to secure higher reliability than evaluating signal intensity when appling FFT to monitoring.

Key Words: Fiber laser, Nd:YAG laser, Plasma, Beam quality, Keyhole, FFT