Bovornchock Poopat and Eakkachai Warinsiriruk

pp. 829 - 840

Abstract

The objective in this paper is to investigate acoustic signal emitted during metal transfer in gas metal arc welding process (GMAW). Short circuit, globular transfer and spray transfer were classified by using dynamic microphone. Mode of metal transfer can be clearly classified and explained by using acoustic signal
analysis in time domain. Acoustic RMS in time domain can also be used as an indicator to determine modes of metal transfer. The results showed that short-circuit transfer, globular transfer and spray transfer signal exhibited acoustic signal RMS of 79.74 x 10^-3 volt, 133.31 x 10^-3 volt and 38.73 x 10^-3 volt, respectively. In
frequency domain analysis, each mode of metal transfer exhibited a certain frequency response range with certain frequencies along the frequency axis. It was found that peak frequency response range short-circuit transfer, globular transfer and spray transfer were 2250 Hz, 5880 Hz and 240 Hz, respectively. The frequency
response curve can be clearly be used to classify modes of metal transfer. This non-contract sensing technique was developed as a real time-monitoring technique for rapid control of welding processes.