Controlled-pulse PAW Control System Based on Backside Keyhole Image

doi:10.3901/JME.2017.06.068

Abstract

Abstract:

The developed controlled pulse keyholing plasma arc welding control system has been verified to stabilize the keyhole behaviour and improve the process stability, confirm the weld quality. However, the system is developed based on the indirect signals to reflect keyhole penetration state, the feedback signal cannot measure the weld pool thermal state. Previous observation studies to the PAW keyhole behaviour find that, keyhole exit positional parameter is better to predicate the weld pool thermal state evolution than the keyhole dimensional parameters, and the decreasing speed of the welding current in pulse waveform is reliable to adjust the keyhole exit deviation distance. In this paper, a novel controlled pulse keyholing PAW control system is designed by using the keyhole exit image as the feedback signal. In the new system, keyhole exit deviation distance as the controlled factor, falling degree in the welding current pulse as the controlling factor, predicative control algorithm is developed. Bead on welding is conducted on the 9.5 mm thick 304 stainless steel plate to test control system, keyhole process is controlled to open and close smoothly, sound quality weld is obtained.

Key words: control system, controlled pulse keyholing, vision-observation, plasma arc welding

HUANG Chunde, ZHONG Liming, LIU Zuming. Controlled-pulse PAW Control System Based on Backside Keyhole Image[J]. Journal of Mechanical Engineering, 2017, 53(6): 68-72.

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