Valmet polarized forming fabrics give great results, case studies

Valmet has constantly improved their forming fabric technology and has developed fabrics providing excellent runnability, high wear resistance, long running time, good paper profiles and good retention. Specialized forming fabric designs for packaging grades continue to improve drainage.

Customer experiences have shown that the polarized forming fabrics have the potential to revolutionize water removal in the papermaking process.

Normal vs. polarized warp structure 

The left image is of a normal structure fabric with straight dewatering channels. The right image is a polarized warp structure with no direct drainage holes. The result is more gentle initial dewatering with improved formation and higher final dry content. Additionally, the polarized structure provides good retention with less fiber bleeding and cleaner running wire loops.

Case study - liner / medium - twin fourdrinier

Twin fourdrinier two fabric layout

A board machine making liner / medium of 23-54 lbs/1000 sqft (110-260 gsm) runs at 3000-3600 fpm (900-1100 m/min) on a twin fourdrinier. Over several years, the machine used a progression of Valmet forming fabrics:

• 2011 - Valmet Forming Fabric CH (2,5 layer)
• 2013 - Valmet Forming Fabric PM (SSB)
• 2015 - Valmet Forming Fabric OP (SSB)
• 2017 - Valmet Forming Fabric OPW (SSB)

Over the 2011 to 2019 period, the machine transitioned to Valmet's next step in SSB technology, the polarized forming fabric for more control. The machine has achieved great run times historically, with many instances of fabrics running over 200 days in both positions.

The result in progression has been a thinner fabric with higher fiber support and the ability to better control drainage and retention with the swings in freeness the machine experiences using a high content of mixed waste. The reliable, rugged performance of Valmet forming fabrics continue to help the machine maintain and exceed production goals since the startup of the machine.

Case study - liner / medium - OptiFormer S/B

OptiFormer S/B two fabric layout

Another board machine making liner / medium of 18-35 lbs/1000 sqft (90-170 gsm) runs at 2000-2600 fpm (600-800 m/min) on an OptiFormer S/B. The machine has a reel width of 303 inches (7.7 meters). Moving to polarized Valmet Forming Fabric OPW resulted in sheet dryness improvement of +1.0 to 3.0% and reduced the power load by 26%.

Improved dryness with polarized Valmet Forming Fabric OPW

Valmet Forming Fabrics have provided a solid anchor point for the machine across the grade spectrum. Stability and repeatability are important keys which have allowed the mill to focus on the remaining bottlenecks to increase machine performance.

For more information about improving your forming process with polarized Valmet Forming Fabrics, check out the Related Links section of this article and contact your Valmet representative.