Benefits of Introducing Optical Caliper Sensor

Abstract

Caliper measurement is unique from others in the sense that it pinches the paper web between the sensing planes for the measurement purpose although a paper quality control system is associated with various measurement functions. This has often become the issues in paper production process making holes and marks by sensing plane touching the paper. In order to solve these issues, non-contacting caliper sensors has been introduced applying measurement principles such as laser measurement. However, these sensors are yet to be utilized for the continuous measurement and control of production lines because they still have some essential technical issues have to be solved.
In such background, Yokogawa Electric Corporation started the development of Optical Caliper Sensor applying the confocal technology and a chromatic aberration for the measurement principle of the sensor. Since the Optical Caliper has actually been tested on line at one of paper mills in Japan during January2008, increasing the number of customers has approved this sensor as the solution to solve their issues. Currently in Japan, all the Optical Caliper installed in Newsprint and White board Machines are utilized for the caliper profile control and have achieved zero-holes, zero-marking and zero-curl related sheet brake.
This paper introduces starting with the history of the caliper sensor, explains the measurement principle and tuning method of the Optical Caliper Sensor, and finalizing with the benefits of introducing this sensor in Newsprint and White Board applications.