With the introduction of a new QCS (Quality Control System) platform just months away, Valmet chose a challenging location for the first pilot system at Metsä Tissue in Mäntta, central Finland. The machine was PM7, producing cooking and baking paper and there were just two days to remove the old QCS scanner and install the new Valmet IQ before the machine went back to full production. Replacement of the old scanner, dating back to the early 1990’s, had become necessary with components reaching end of life and performance no longer meeting Metsä Tissue’s exacting requirements.
The Valmet IQ quality management solution is designed and built with the experience of just over 1000 quality control systems delivered by Valmet, including those on Mänttä’s three tissue machines. IQ is a comprehensive product family covering measurements and scanners, profilers and web inspection systems with a suite of control and information applications that enable papermakers to reach their quality targets as well as providing a clear view to the papermaking process. Customized IQ systems are fully scalable, from a comprehensive quality management system to part of a stand-alone solution for particular quality tasks on the paper machine.
The Valmet IQ scanner, with caliper, moisture and basis weight sensors, was initially assembled by the machine for final system checks before installation. The cooking and baking papers produced on PM7 are in great demand and downtime for the new scanner was limited by full order books to only two days in March 2015. Time was not the only constraining factor, according to Jyrki Pekkala, mill maintenance manager, “There were only a few centimeters to spare when installing the new scanner but everything went amazingly well and we kept the schedule. The new scanner and measurements operated right from the word go and we were back in production.” Machine operators were immediately impressed, commenting that measurements are now more accurate and dependable, essential qualities for them to perform their duties.
For Sauli Seikkula, Valmet service engineer, the installation of the new design scanner was pretty straightforward. “It looks really good too,” he says, “The transparent doors on each end remove a little of the black box appearance and mill personnel experienced something of a wow factor seeing it for the first time.” Connection to the mill’s existing DCS is via an Ethernet cable, unlike earlier scanners all signal and measurement handling is done in the scanner thus eliminating any additional hardware in the cross connection room or control room. “It really simplifies the installation with no additional process stations or I/O and provides a faster boot time from a cold start.” As part of an existing long term service agreement Seikkula or other Valmet service colleagues typically spend two days a week at the mill to look after the DCS and QCS equipment on PM7 as well as the mill’s three tissue machines. “In four months, since start up, the new scanner has performed well with no need for any special service actions,” commented Seikkula.
Silicone dust is one factor the new scanner has to deal with. A silicone coating helps give baking paper its non-stick property and capability to withstand the temperatures involved in cooking, it also tends to coat all exposed surfaces around the machine. As well as compressed air cleaning of the scanners paper path every 5th scan, manual cleaning by a machine operator is made much easier with the IQ scanner. Unlike the old scanner, the measurement heads either side of the web on the new IQ can be uncoupled for easier servicing. A small operating panel on the scanner frame allows the scanner head to be locally controlled which makes visual inspection of the sensors much faster and more effective than earlier.
As well as being totally compatible with the mill’s existing equipment, the new IQ system also provides forward compatibility thus making future automation investments easier and more effective. This approach is evident an all of Valmet’s automation offerings, a lifelong support program that will ensure a continued return on Metsä Tissue’s IQ investment as well as maximizing the useful life of existing equipment.