Using sound and vibration signals to monitor cell wear on anilox rolls

In flexo printing industry, it is very important to maintain an even thickness of ink film to guarantee colour match, density, and sharpness of printed forms. The anilox roll is the key process roll used in preparing the ink film for printing. A major defect of the anilox roll is the cell wear. Current anilox cell wear analysis is usually performed using offline optical techniques. The objective of this research is to investigate the feasibility of utilizing sound and vibration signals to determine the level of cell wear. Vibration of the doctor blade interacting with the roll cells was detected by accelerometers. A microphone sensor was used to monitor the sound emitted off the interaction zone. Both the power spectral density (PSD) and the short-time frequency transform (STFT) showed that the spectral peaks, for the sound and vibration signals, decreased in magnitude and shifted in location as the anilox cells deteriorated. The results are the first in this field and show great promise for developing an online anilox roll nondestructive testing system.