THE QUALITY CONTROL SYSTEM UPGRADE DECISION

摘要

In today's economic environment, where competition is intense among producers of all paper grades, it is interesting to note that few paper machines operate at the highest possible production efficiency, or produce the best quality product that the machine is capable of delivering. This may be partially attributable to an aging quality control system (QCS) which lacks new tools and capabilities, introduced in the last few years, which can enable papermakers to compete more successfully in today's market. Some existing QCS shortcomings may be visible, such as a profile control that is ineffective because individual actuators are set to both minimum and maximum setpoints across the paper machine. Other disadvantages may be invisible, such as limited profile measurement and control response speed, resulting from slow scanning. This paper examines the decisions to be considered in determining if a QCS upgrade is justified. The requirements for quality measurements, control applications, cross-direction actuators, system reliability and support, and platform hardware and software will be discussed relative to available QCS upgrade or replacement options. Real-world examples of QCS migrations are included to illustrate paper production efficiency and quality improvement opportunities.