Is there evidence of determinism in droplet detachment within the gas metal arc welding process?

摘要

For many years, the welding community has assumed that the detachment events within Gas Metal Arc Welding (GMAW) process are stochastically driven. With this in mind, we set out to better understand these mechanisms and what might drive the detachment events. Through the investigation of 6061-Aluminum GMAW, a number of new insights into globular, and spray transfer modes have been found. By using windowed Fourier transform analysis, akin to Wavelet Analysis, we present evidence that the GMAW process undergoes a shift from the globular mode fundamental frequency to its secondary harmonic frequency as the GMAW process shifts from globular to spray mode transfer. This breakdown and shift from primary to secondary fundamental frequencies and its reverse are shown to occur often within the transition-welding mode in aluminum GMAW. Furthermore, there is partial evidence that this shift of fundamental frequency modes from secondary to the third fundamental frequency continues with the transition from the spray to streaming transfer. The evidence for determinism as the driving force behind GMAW detachments is strengthened through chaotic systems analysis, e.g. surrogate testing using ApEn statistics.