Abstract: On the basis of the study on are spectral information of droplet transfer in pulsed MIG welding, the spectral control method of droplet transfer in pulsed MIG welding is put forward and realized successfully, Experiments show that droplet transfer keep all to One-peak-zero-base type under controlling by this method as the welding parameter varies, such as peak current, base current and pulse frequency, This method has strong capability to precisely control droplet transfer and therefore it is very beneficial to making stable welding process and superior welding quality. It has also many other advantages, such as the strong interference-resistance, the wide technology scope and the convenient on-line adjusting property etc. In addition, this method is expected to be used to control droplet transfer of two-peak-zero-base, three-peak-zero-base and so on. Thus, a novel method is found for the automatic control of welding process and welding quality in pulsed MIG welding. Experiments also show that the converting method at the back of the spectrum peak is the optimum control tactics. The control system, principle, control tactics, welding parameters, experimental result and its analysis of this method are discussed.

Key words: Automatic control, Droplet transfer, One-peak-zero-base, Pulsed MIG welding, Spectral control method