The unique OptiCalender Metal Belt features a long-nip calendering technique that provides boardmakers with a major quality and efficiency boost. The possibilities to increase profit with very high surface quality and decrease raw material cost with the increased bulk are evident.
The secret behind OptiCalender Metal Belt calender lies in two factors; an extremely long dwell time and the most effective plasticization. OptiCalender Metal belt’s dwell time is 4-15 times longer than with a shoe nip calender and 100 times longer than with a conventional soft nip calender. Effectively plasticized surfaces provide low surface roughness values, good printing quality and a low post-roughening tendency after calendering.
With OptiCalender Metal Belt, the traditional calendering nip has been replaced with a one-meter-long machine-direction calendering zone. The OptiCalender Metal Belt has a smooth, heated metal belt and a thermo roll that calenders both web sides simultaneously in one extended zone.
Metal belt calendering is the ultimate method for bulk saving. It allows significantly higher heat transfer and plasticization, resulting in extremely high bulk and stiffness. Thanks to its one-meter-long processing zone, superb printing quality is achieved while maintaining high strength properties. This enables raw material optimization with savings potential – as much as 10% higher potential than with a Yankee cylinder. Consequently, this generates substantial raw material savings and increases yield.
The numbers behind fast payback are hard to believe. The saving potential with production increase, raw material savings and bulk saving can be counted in millions. An article about Zhuhai S.E.Z. Hongta "How about saving millions?" clarifies these figures almost too hard to believe.
In terms of surface properties, the formation scale smoothness is improved, resulting in extremely flat and smooth surfaces and enhanced visual appearance on both sides of the board. For converters, this means excellent printability and consistent ink setting, as well as a decreased tendency towards print mottling.
By using OptiCalender Metal Belt, the board surface quality is outstanding:
What more can you hope for? We invite you to carry out your calendering trials at Paper Technology Center. All calendering technologies can be tried out with your own paper or board.
Thanks to its simple and compact design, the OptiCalender Metal Belt is especially suitable for rebuilds. The calender provides 40 - 60 % more production by removing existing bottlenecks, such as the Yankee cylinder and wet stacks.
OptiCalender Metal Belt is easy to use. Linear load is the only control parameter that needs adjusting in the calendering process. Two-sidedness can be controlled with temperature. Also the operating window is large. The example in the figure below shows the comparison of coated board calendering (the quality level and bulkiness).
The calender maintenance is also easy because of the opening front. Additionally, the metal belt life time can reach even two years (see article about metal belt lifetime record).
Former ValZone metal belt calender has been included in the OptiCalender family as OptiCalender Metal Belt.
Strong partnerships are built on people. “We work as one team and have built many personal relationships over the years,” says Jorge Aldana, Director of Project and Industrial Development at CMPC Papeles. This is a story about people working together towards a common goal. CMPC Chile describes it as a strategic partnership with Valmet.
During a ceremony in Stockholm on October 1, 2012, the Swedish King, His Majesty Carl XVI Gustaf awarded the Marcus Wallenberg Prize 2012 to Mika Viljanmaa, Valmet, for his ground-breaking development of metal belt calendering technology.
Paper and board makers have been focusing their attention on increasing their output in tonnes. A paper machine is not considered to be functioning well if its output in tonnes drops, even if this is due to improved bulk and reduced use of fibers. Environmental considerations and cost competition are forcing to rethink the processes. Boxes are not made of tonnes but board sheets.
Roll cover decisions are complex; the prices, performance characteristics and cover lifetimes vary considerably. Answering these five questions can guide papermakers in making a better choice among today's wide range of roll cover technologies.