Making perfect paperboard
2013-11-06 - An ABB solution is helping StoraEnso make perfect paperboard by detecting defects with millimeter precision at high speed.
By ABB Communications
KM8 at StoraEnso’s Skoghall mill in Sweden is the world’s largest paperboard machine. Almost 300 meters in length, it produces up to 450,000 tons of paperboard a year, most of which is made into liquid food cartons all over the world. About 20 percent of milk cartons worldwide are made from paperboard that was produced by KM8.
Quality is key in the liquid food industry. The paperboard has to match the customer’s requirements perfectly. It has to fold correctly into a customized carton that is stable, easy to hold, and has the correct printing properties for a color-rich carton design.
“[This is] a unique system that inspects every square millimeter of paperboard as it speeds through the machine at 800 meters a minute.”
Quality is also key for StoraEnso, the world’s second largest paper company and a market leader in paperboard. Recently, with its existing surface inspection system reaching the end of its operating life, StoraEnso approached ABB for a new solution that would take quality control to a new level.
Based on ABB’s HDI800 web imaging system, the solution is the biggest surface inspection system ever made. Its 100 cameras and ABB algorithms detect, photograph, analyze and classify the defects and alarm the operator whenever it finds an imperfection.
“Together with ABB we’ve developed a unique system that inspects every square millimeter of paperboard as it speeds through the paperboard machine at 800 meters a minute,” says Björn Wikström, maintenance technician at Skoghall.
The system has not only enhanced quality and improved the operators’ working environment, it has also significantly reduced the number of paperboard rejects.
“Previously, some customers might reject an entire shipment if there were blemishes in some of the rolls,” says Leif Karlsson, project manager at Skoghall. “Now we can identify and remove those rolls that do not meet each customer’s quality requirements. The cost savings are immense.”
Another benefit of the ABB solution is that it enables operators to quickly detect repetitive flaws caused by a damaged roller or other component in the paperboard machine. The solution has also reduced the number of sheet breaks by 80 percent; these are usually caused by holes or other defects.
Recently, ABB developed another world-first capability for the Skoghall solution that detects shearing defects in the paperboard. These are small wrinkles that are invisible to the naked eye but cause many rejects and are time-consuming to troubleshoot.
Last but not least in the long list of benefits is improvement in energy efficiency. “Reducing the amount of rejects has resulted in significant energy savings” says Leif Karlsson. “Each meter of product that we have to reject due to defects and flaws is a waste of energy.”
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