Voith modernizes Braviken PM 53
Successful upgrade to SC papers
2015-12-03 - Voith completed the rebuild of Holmen Paper’s PM 53 in Braviken, Sweden, from newsprint to magazine papers and successfully commissioned the modified machine. Since the upgrade, Holmen Paper has been producing its newly developed SC paper Holmen UNIQ on the PM 53.
Ready to go after three-week rebuild. The PM 53 paper machine was supplied and commissioned by Voith in 1996. Early 2015 saw a new chapter in the history of the PM 53. As part of a three-week rebuild, Voith replaced the former EcoSoft calenders with a 10-roll Janus MK 2 calender, converted Nipco rolls and steam boxes so that they could still be used, relocated the existing MasterReel reel winder and retrofitted new LunaReel rubber roll covers to its reel and standby drums. The reason the rebuild could be completed so quickly was because the new calender was put on the existing paper machine foundations. This means it is on the same level as the paper machine, which is possible due to the 45° incline of its roll stack. This results in further benefits like lower susceptibility to vibrations and very easy access allowing for shorter roll change times. The hard calender rolls are equipped with TerraGloss by Voith. TerraGloss is a hard metal thermal coating for calender rolls. It optimizes paper finishing by improving the profile accuracy, smoothness and gloss of the paper. TerraGloss is produced with hard materials on a carbide and nitride basis and for that reason has a high level of resistance to chemical and mechanical influences. Another advantage of TerraGloss is its extraordinarily good heat transmission which contributes to energy savings in the calender.
A special feature of the Janus MK 2 calender is the NipProtect system, which allows all roll nips to open simultaneously in distinctly less than half a second and then deposit the rolls gently without damaging them so that roll covers are also protected from being overheated and damaged.
Competitive and flexible. Holmen Paper was happy with the cooperation with Voith and the paper quality as Production Manager Jenny Melander confirms: “The paper was already of a very good quality directly after startup.” The rebuild not only allows Holmen Paper to return to the SC segment but also to enhance its flexibility. Because if required, the PM 53 can switch between single, double or multi-nip operating modes of the calender at any time without interrupting production, enabling it to produce paper qualities ranging from matt to glossy and from low to high density.
The reason for converting the PM 53 to SC papers was so that it could produce the new Holmen UNIQ grade, which had been developed in the company’s laboratories. With Holmen UNIQ the manufacturer wants to offer its customers “more paper for their money”. Karolina Svensson, the Group’s Marketing Director, explains how it works: “With Holmen UNIQ we have developed a paper that has a higher bulk and lower grammage but offers the same quality feel. Due to its light weight, our customers get up to 16 per cent more surface area for the same price.” This is possible because of the 100 percent virgin fibers used as feedstock and the new Janus MK 2 calender from Voith that was retrofitted to the PM 53. The new paper grade is offered in the basis weights 43 g/m2, 47 g/m2 and 50 g/m2.
To Janus MK 2