Defect detection system at Stora Enso Imatra

Stora Enso Imatra Mills is the largest manufacturer of liquid packaging board in the world. Consumer packaging board used in contact with food and liquids must meet strict quality requirements set for food safety. What is more, no flavours can dissolve from the board into food products, and the products must be first-rate in terms of visual cleanliness.

For several years, systems supplied by Procemex have been used in Stora Enso’s board machine 4 (BM4) to indicate any defects in board quality and to reduce web breaks. In March 2016, Stora Enso Imatra Mills made a system modernisation investment to improve the quality of food packaging board and increase the efficiency of the board machine.

About the upgrade system

“We compared three different suppliers Riku-Suurnakki-Stora-Enso-Procemex and ended up with Procemex, first of all, because we have had positive experiences with the previous system and, secondly, because we were able to upgrade the previous system – without needing to acquire a completely new one. We also investigated what benefits we can gain from the upgrade. In the end, the decision was an easy one; after all, we obtained a wholly new system by simply upgrading the old one,” says Mr. Riku Suurnäkki, Production Manager of BM4.

“Both web break and web inspection/defect detection systems are critical elements in order to be able to operate these machines: web inspection in terms of the final cleanliness and the web break system in terms of production efficiency. If we encounter any problems with efficiency, the web break system allows us to identify the root cause of breaks, enabling us to resolve, or even eliminate, the problems.”

Stora Enso Imatra Mills defined new locations for cameras, together with machine operators, and, now, cameras indicate the locations where pulp starts to pile up. “Of course, it is essential to listen to users,” Suurnäkki says.

“The new system became a necessity after we identified that we need to improve the classification of defects and the usability of the system. The previous system was unable to reliably classify a certain common defect, and there were situations in which defects in board ended up in our plastic coating,” says Suurnäkki.

About the benefits of the upgrade

The new upgraded Procemex cameras have a significantly higher resolution, defects are now classified more closely, the detection of defects is now more visual and the system is easier to configure for each user.

“We can better detect any dirt and impurities,” says Vesa Koskinen, system specialist at Efora, who is responsible for the maintenance of the BM4 system.

“On our part, the project did not get off to a textbook start, and we were forced to speed up the process. Procemex did an excellent job, even though the order-delivery schedule was very tight. The installation period was also tightly regulated and brief, but Procemex was able to ensure the resources required,” says production manager Riku Suurnäkki. “Commissioning, adjustments and links to mill systems – everything was done on time.”

“The experience we have had so far indicate that the detection of defects is now much more visual than in the previous system, and the classification of defects has improved. Operators have already given us direct positive feedback, saying that the image quality is on a completely different level and, therefore, there are fewer web breaks,” Riku Suurnäkki says.