Paper Web Edge Position Measurement SystemSince the developments in paper making technology and the growing production speed of paper machines call for accurate measurement and control of the web position, thus presenting new challenges to paper web edge recognition technology, Vision Systems Oy a recognized company dedicated in developing and manufacturing of machine vision products, has recently introduced a VISIEDGE Paper Web Edge Position Measurement System which provides the perfect answer to these new challenges.VISIEDGE system is based on modern CCD line scan camera technology and it comprises integrated measurement and illumination unit in air-cooled industrial housing as well as advanced user interface software and field cabin including necessary electronics and power supply. The system can be utilised with both reflected and back light and the measurement area at both edges of a paper web with two separate measurement heads is 200 mm.
Reliable
and extremely accurate
VISIEDGE system measures in real time with 100 % coverage paper web edge positions and thus concurrently the width of the paper web. The system provides extremely accurate non-contact measurement and it can be installed even in harsh paper mill conditions near by a guide roll or a calender where paper web is running stable. Due to the fact that paper web does not flap the measurement results provided by the system are very reliable.
Benefits at paper machine and supercalender Since its introduction VISIEDGE system has gained remarkable benefits for paper makers by providing accurate and comprehensive measurement data regarding paper web edge positions and web width at dry end of paper machine in order to utilise that information for CD control of dilution head box. As another one application VISIEDGE system has been exploited at supercalender where the system enables implementation of an automatic and non-contact paper web guidance during oscillation of a paper web. Thanks to VISIEDGE system an operator of a supercalender is now able to concentrate on more value added tasks. Recent successful exploitation at winder applications As the latest application VISIEDGE system has been successfully exploited at winder in order to minimise edge trimming of a supercalendered paper roll. In normal operational conditions at supercalender a paper web is oscillated continuously, for instance, 50 mm from left to right and back in order to avoid uneven wearing of rolls in calender’s roll stack. Consequently, in the next process phase at winder should be implemented winding off of paper roll’s oscillation in order to minimise trimmed strip.
Thanks to VISIEDGE system’s accurate and noncontacting camera technology the winding off of paper roll’s oscillation can be carried out with a very narrow tolerance. For instance, in the case when a paper web has been oscillated 50 mm at supercalender, minimum width for a trimmed strip at winder is 25 mm and tolerance is +/- 5 mm, then trimmed strip utilising VISIEDGE system varies between 25 - 35 mm. In that same case, if you don’t use winding off of paper roll’s oscillation at all, trimmed strip varies between 25 - 75 mm. In normal case both edges of a paper roll are trimmed at winder and then an average yield difference between edge trimming carried out with or without VISIEDGE system can be even 2 x (50 - 30) mm = 40 mm. There is also on a market mechanical and inductive guards which are able to carry out oscillation of a paper web on a supercalender or winding off of paper roll’s oscillation at winder, but the tolerance which they need for edge trimming is clearly higher than the tolerance utilised with camera based VISIEDGE system. Earning money through material savings Consequently, the above mentioned calculations and statements illustrate clearly that VISIEDGE system provides significant material savings in form of trimmed strips for paper maker’s at winder application. This is an exemplary case how a paper maker can easily earn more money without raising production capacity but with making modest investment for VISIEDGE measurement systems. Contact:
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