Single CCD-based sensing of both keyhole exit and weld pool in controlled-pulse PAW
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The controlled-pulse strategy is proposed to improve the keyholing stability and dynamics in plasma arc welding (PAW). A cost-effective vision system is developed to acquire both keyhole exit and weld pool images from backside of workpiece in controlled-pulse PAW. With a specially designed optical filter, the images of low-intensity weld pool and high-intensity keyhole exit are obtained simultaneously by one single CCD camera. The dynamic variations of both keyhole exit and weld pool are successfully monitored. The influences of welding current waveform parameters on the dimension and position of keyhole exit and weld pool are measured. The effects of the waveform parameters of the controlled pulse on the establishment/sustainment periods of keyhole exit and the positions of first/last keyhole exits in a pulse cycle are elucidated experimentally.
KeywordsPlasma arc welding Controlled-pulse keyholing Vision-based sensing Keyhole exit Weld pool
The authors are grateful to the financial support for this research from the National Natural Science Foundation of China (Grant No. 50936003).
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