Research And Application Of The Tandem Pulsed Coordination Controller On DC Welding Power Source

As the modernized industry developing, efficient welding technique is great pushed forward. High-efficiency of welding has become an exigent request. However, the tenacity will decline and the size of grains will increase with the overheating coarse grain zone expanding in the heat-affected zone (HAZ), it will have poor shaping. Therefore, the quality of welding drops down. In order to assure quality as well as high-efficiency, Tandem double-wire pulsed MIG welding is put forward in this paper, and the controller for it is developed.The pulsed controller, with micro-controller unit (MCU) as the core, light emitting diodes (LED) and keyboard as the man-machine communication interface, has been designed and developed in combination with electronic technology, automation theory and MCU technology. The controller can make the voltage change in frequency and amplitude on the base of a certain value. Hence, it can both control the heat input, which achieves refinement of HAZ structure and improve the tenacity, and shake the molten pool regularly to broken the grain. Furthermore, the controller is designed for duplex output according to push-pull mode, which can be applied for double-wire welding.During the welding process, photoelectric signal testing and analyzing system is applied for electric signal sampling such as welding current, voltage waveform and so on. Besides, high speed photograph is used in step of electric signal sampling, to analyze the droplet transition, arc behavior and its effect on welding current and voltage.Experiments prove the function and reliability of the controller. Welding parameters are optimized by adjusting the peak and base voltage value, pulse frequency, duty ratio and so on. It can be guide of high-efficient welding method and new double-wire pulsed welding machine.