M3 WIS Replacement Project: Practical Experiences using Procemex Twin system

摘要

Maryvale M3 is an 80,000 tpa fine paper machine producing mainly uncoated wood free copy and printing grades. In June/July 2012, M3 experienced a sudden increase in number of customer's complaints about starch debris in the sheet. Immediate actions were taken to resolve/mitigate the issue but one particular concern was that starch debris reported by the customers had not been detected or recorded by the Web Inspection System (WIS) at the time of manufacture and going forward, would most likely fail to report any possible re-occurrence. Testing confirmed that the WIS was not detecting the starch related debris. This situation was unacceptable and a solution was required The M3 Measurex system installed in 1998 was obsolete, leaving little option but to replace the WIS system. Samples of starch debris were provided to a number of potential suppliers of Web Inspection systems. All the WIS suppliers were able to detect the presence of the defects in the paper but it was immediately obvious that images taken of the starch deposits were highly variable; some were dark like dirt while others were almost transparent. This meant that detecting the defect would be easy; but classifying the defect correctly would be very difficult. The selection process identified the Procemex Twin system as the best system able to provide a cost effective solution to replacing the WIS and also had the best approach to address the defect classification issues Procemex approach to the problem was innovative. They proposed using a single camera beam but with two light beams. One above the sheet to capture defects images in reflected light and the other below the sheet for transmitted light. Information from the two images is then combined in a post classification process to identify starch type defects from other defect types. Another significant consideration was the offer of two Web Monitoring cameras to compliment the WIS. The Procemex system was installed in March 2014 and in the past year of operation the Procemex Web Inspection/ Monitoring cameras has been pivotal in achieving the following: 1. Zero customer claims for starch debris type defects. 2. Development of improved strategies for managing starch deposits. 3. Identification of additional starch deposition mechanisms. 4. Significantly reduced sheet breaks. 5. Reduced sheet defects such as holes. 6. Improve machine hygiene monitoring. 7. Greater Operator involvement and decision making. The M3 WIS replacement is viewed within AP as being a very successful project, not only delivering the project objectives but also generating substantial returns beyond the original scope.