2018 年 18 巻 3 号 p. 192-198
To improve surface quality, the jet wiping method is used to control the coating thickness in a continuous galvanizing line. In this study, we adopted structural technology for the wiping nozzle with the aim of suppressing nozzle clogging, which is the main problem with the standard wiping process, and reducing the uneven coating thickness in the direction of strip width. We adopted a laminated piezoelectric device for the actuator, which is a key smart structure technology, and attempted to change the nozzle gap statically / dynamically. Regarding the static change, it was confirmed by the actual nozzle that the actuator specification could be examined by FEM analysis and a gap change of about 0.1 mm would be possible. We also succeeded in vibrating at high frequencies of 20 μm amplitude and 810 Hz by utilizing the resonance in the opening and closing vibration mode of the upper and lower lips. The nozzle was subjected to an on-line test in an actual plant, and suppression of nozzle clogging due to high frequency excitation and great improvement of the distribution of coating thickness in the direction of strip width due to expansion of the gap were confirmed.
