Exact web-edge detection in paper production

Calenders are used in paper production and should improve the surface smoothness of the final product which is e.g. printed newspaper or brochure paper. If movement of the paper web in the calender is not exactly executed in one line, the heated calender roller is pressed directly onto the coating of the opposite roller, which can damage it. Repairing this special coating or even replacing the whole roller would be very costly.

This is where laser profile sensors from Micro-Epsilon are used to control the web edge, detecting the exact position of the web edge and directly transferring the measured values to the machine control system. Measuring both edges of the web enables the web width to be determined and to transmit this value to the next stage of the trimming process. Compared to camera systems equipped with back lighting, this one-sided, absolute measurement solution using laser scanners saves significantly more space and doesn’t need to be removed and set up again when changing the rollers, greatly reducing maintenance and service times.