High Signal to Noise Ratio Weld Pool Imaging Device Research in CMT+P

A clear, arc-free weld pool image is the foundation for molten pool visual processing. In this paper, light intensity and welding current during CMT+P welding are captured synchronously through the photodiode and FPGA device. Through analyzing the light intensity and welding current, the CMT phase is detected by the current signal. And verified the accuracy by a high-speed digital camera. A suitable filter is realized by the FPGA to judge the CMT phase adaptively and trigger the camera to capture the weld pool images. A large mount online experimental results have demonstrated that this scheme can capture clear and high signal to noise weld pool images with almost no arc interference, which lays a solid foundation for weld pool vision based on CMT+P welding.