Analysis of molten pool dynamics in laser welding with beam oscillation and filler wire feeding

Molten pool flow and heat transfer in a laser welding process using beam oscillation and filler wire feeding were calculated using computational fluid dynamics (CFD). There are various indirect methods used to analyze the molten pool dynamics in fusion welding. In this work, based on the simulation results, the surface fluctuation was directly measured to enable a more intuitive analysis, and then the signal was analyzed using the Fourier transform and wavelet transform in terms of the beam oscillation frequency and buttonhole formation. The 1st frequency (2 x beam oscillation frequency, the so-called chopping frequency), 2nd frequency (4 x beam oscillation frequency), and beam oscillation frequency components were the main components found. The 1st and 2nd frequency components were caused by the effect of the chopping process and lumped line energy. The beam oscillation frequency component was related to rapid, unstable molten pool behavior. The wavelet transform effectively analyzed the rapid behaviors based on the change of the frequency components over time. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

In this study, molten pool flow and heat transfer in laser welding process with beam oscillation and filler wire feeding were calculated using CFD. The surface fluctuation was measured and analyzed with Fourier and wavelet transforms to study the beam oscillation frequency and buttonhole formation. The wavelet transform effectively analyzed rapid behaviors based on the change of frequency components over time.