Study On Robot Twin-wire Co-pool Pulsed MAG High-speed Welding&Behavior Of Droplet Transfer Under Synergic Control

Robot twin-wire co-pool pulsed MAG high-speed welding (robot TCGMAW) technologypossesses the advantages of high efficiency, quality and automatization, and is paid muchmore attention nowadays; it has become the research focus in the welding field. Nevertheless,our country’s research on it commences late and can’t produce this kind of robot twin-wirewelding equipment in batch production. Under the foundation of National Natural ScienceFoundation of China (No.50375054) and the Project of Guangdong Province Science andTechnology Plan (No.2010B010900027), on the basic of theory analysis, based on thetechnology of digital control and digital communication, this paper presents a thoroughresearch on robot TCGMAW and TCGMAW’s droplet transfer and welding seam on differentwire feeding speed, pulse frequency and phases.In this paper with TCGMAW based on the welding robot and numerical synergic controlsystem built with C/OS-II embedded operationg system, the modern computercommunication system between the twin power sources and the wire feeders was designedand implemented which decreased the quantity of communication data wires between the twinpower sources and the wire feeders, reduced the probability of failure, increase theproductivity.The mathematical model of TCGMAW dynamic process based on the welding robot wasestablished, based on it the TCGMAW dynamic process was simulated and analysed;considered that there was intimate relation between droplet transfer and time constant of arcwelding power source, but there was no evident effect on wire extension; after wire extensionturbulencd system recovered to its original stable working point; but arc lenth turbulencemade the system stable into a new working point.The key probems under synergic control in TCGMAW were researched, by the high-speedcamera and the wavelet analysis instrument, the effects on TCGMAW’s droplet transfer andwelding seam on different wire feeding speed, pulse frequency and phases were analyzed.Using the theory of fluid stability the effect of TCGMAW’s pulse phases relation of frontwire and back wire to welding formation was explained, considered that under the mode ofsynchronized phase control the main reason of welding pool instability and formatting finalhumping bead was the twin wires causing the welding pool elongated.The synergic control was tested with TCGMAW based on the welding robot computertesting platform; the over-all tests under twin-wire synergic control were accomplished.Combined with the research of twin-wire droplet transfer in this paper, considered that under alternate pulse phase the welding result was better than that under random pulse phase, andthe welding result under random pulse phase was better than that under synchronized pulsephase. On the whole high pulse frequency enhanced the arc stiffness and thereby made thewelding seam better, but over-high pulse frequency decreased welding seam quality.The study on TCGMAG based on the welding robot and behavior of droplet transfer undersynergic control in this paper will provide theoretical and practical fundamental evidence andreference.