MM Količevo BM 3: Investing for the future with OptiSizer Curtain

The investment for the board machine consisted of three main updates: the dryer section rebuild; new sizing technology; and a new winder. “We noticed that proactive measures were necessary to ensure the organization’s preparedness for the future, so we decided on this investment because we saw different market needs approaching. The key targets for the rebuild were to produce different board grades sustainably with improved product quality and a lower CO₂ footprint. At the same time, we were able to improve our energy efficiency and increase production capacity,” says Michael Petschacher, Managing Director at MM Količevo.

The design of BM 3 is very specific because it needs to fit three different kinds of boards.

MM Količevo’s BM 3 board machine produces three product classes, making the rebuild project unique. “We produce practically all kinds of boards, from folding boxboard and white lined chipboard to linerboard. That’s why the design of the board line is unique: It needs to fit all three different board types,” says Rado Kunavar, Operations Director at MM Količevo.

A flexible innovation in sizing

The most significant modification made during the rebuild was the installation of OptiSizer Curtain. Prior to the rebuild, MM Količevo’s BM 3 board machine did not have a sizer. Quality and lightweighting challenges meant the board machine needed a sizer that could fit the limited space and be sufficiently flexible to fulfill all the different requirements of the wide product portfolio. “We decided to use the prototype technology in sizing because it was the only technology flexible enough to fulfill all our product portfolio’s requirements,” says Kunavar. Unlike other sizing technology, curtain sizing allows the use of high starch solids content and the adjustment of nip load, making it a flexible option for board machines that manufacture many different grades.

The prototype’s start-up was successful, and the machine produced sellable product immediately. “OptiSizer Curtain is a special technology. After half a year of testing, we can say it was the right decision for our product portfolio,” continues Kunavar. The investment for the sizing technology also included the installation of new chemical systems, as well as OptiDry Turn and OptiDry Coat drying technology.

The first-ever curtain sizer was installed in MM Količevo’s BM 3 board line.

State-of-the-art safety

In addition to new sizing technology, the rebuild consisted of two other major upgrades to the board machine: a rebuild of the dryer section and a new winder. The rebuilt dryer section contains some of the newest technology on the market, including steel dryer cylinders and the Valmet Fold-up Wall. The new dryer section includes a unique innovation that allows the doctor blades to be changed while the machine is running.

Overall, MM Količevo has had good experiences with the dryer section since the start-up: “We installed the Valmet Fold-up Wall, which is very important, especially in triple-tier dryer groups. It gives you quick access during breaks, and it cools down very quickly. It’s also important for maintenance because you can open the whole dryer section from the tending side,” says Kunavar.

Valmet Fold-up Wall allows easier maintenance of the dryer section.

The winder was also upgraded with an OptiWin Belt winder during the BM 3 rebuild. Capacity and safety goals were the top priorities in the winder investment. “We chose OptiWin Belt because it’s the only technology which also brings you the lowest loss of bulk, especially in folding boxboard qualities, and which ensures that the stiffness is also maintained after winding,” explains Kunavar. “From the safety perspective, this machine is state-of-the-art,” Kunavar says.

The new OptiWin Belt winder at the MM Količevo mill increases capacity and improves safety.

Successful collaboration at every step

The BM 3 rebuild project was a continuation of an already successful cooperation. And just like the BM 3 coating section rebuild Valmet executed in 2015, the cooperation between MM Količevo and Valmet was close every step of the way. Strong support from Valmet R&D was essential to ensure the prototype technology’s successful start-up. “I must say this was one of the most exceptional experiences of my professional career. The technology Valmet offers is top-notch, and the knowledge and expertise of their engineering team are remarkable,” says Kunavar.

Valmet’s Project Manager, Marko Turunen, and MM Količevo’s Operations Director, Rado Kunavar, examining the OptiSizer Curtain.

Text: Veera Silakoski