Lenzing Papier has achieved record running times with Voith’s TerraGloss coatings on the hard calender roll at its paper mill in Lenzing, Austria. The PM 1 calender rolls with the TerraGloss hard metal coating from Voith enjoy a much longer service life and achieve record-breaking running times of more than 24 months.
“As well as a considerable extension to the grinding intervals, the TerraGloss coatings on our two calender rolls have also achieved a sustained improvement in roll quality in respect of the profiles of our broad range of paper grades,” says Franz Gstettenhofer, member of the management board of Lenzing Papier.
The company specializes mainly in the sustainable production of offset and copying paper based on recycled fibers as well as envelope and packaging papers. Before it opted to use Voith’s TerraGloss coatings, its uncoated chilled iron rolls had to be disassembled and reground every two to four months, depending on the paper grades involved, which was a very time-consuming and cost-intensive process.
By contrast, the wear-resistant thermal TerraGloss coating only needs refinishing after its long period in service, saving both time and money. In addition, using TerraGloss means that the surface quality of the calender rolls can be kept stable for a very long time due to optimum blade conditions, which helps ensure safe and high-quality production. This means that especially in the case of coated paper grades, doctoring with bronze blades like Voith’s SkyTerra B coated bronze alloy blade can be readily optimized with TerraGloss.
Smoothing and calendering, which involves extensive use of various fillers and additives, is a very challenging process, especially in the case of specialty paper grades. The calender rolls coated with TerraGloss optimize paper finishing thanks to improved profile accuracy, unique smoothness and higher gloss level of paper, paperboard or corrugated cardboard.
The innovative hard materials of the TerraGloss coating are based on carbide and nitride. “This gives the rolls high resistance to chemical and mechanical influences,” says Hasso Jungklaus, Senior Product Manager Thermal Coating at Voith. “Moreover, TerraGloss has exceptionally good heat transfer properties, which helps save energy use at the calender.” TerraGloss is applied to hard calender rolls and is suitable for all paper grades. For optimum calendering the SkyTerra B blade should be used. It has a non-stick coating that prevents fouling on the rolls. SkyTerra B can be used with a large number of applications and is manufactured with very fine tolerances.