Optimized fabric designs lead to increased productivity and better paper quality, Solutions!, Online Exclusives, May 2005, Vol. 88(5)

Paper machine clothing was the main topic of discussion at the Zellcheming and VPM Group conference held in Düsseldorf last year. Specialists from Wangner and Huyck, leading fabric and press felt manufacturers, presented current developments and new measuring techniques that significantly enhance both productivity and paper quality. Today’s paper machine clothing specifications are primarily being driven by more stringent quality standards in paper production and the increased demands placed on paper machines.

Karl Betz, design and application engineering manager at German firm Wangner, presented a paper that focused on quality and productivity improvements achievable through the use of structurally bound forming fabrics. Wangner has been able to achieve outstanding results on a variety of paper machine types by systematically advancing its Optiply family of structurally bound compound fabric products, which in turn has led to a high level of acceptance among paper producers. Under the heading “360° Optiply Clothing,” the Reutlingen-based forming fabric specialists have continuously expanded their structurally bound fabric design family and optimized all of its performance parameters (Figures 1 and 2). Every one of the company’s fabric applications now features excellent sheet formation properties and high fabric stability. Three unique performance characteristics have emerged:

• Outstanding fabric topography with a uniform imprint of warp and shute guarantees top formation and retention behavior.
• The design’s inflow funnels throughout the fabric mesh and high fiber support capability produce outstanding drainage performance.
• The improved fabric tension profile resulting from the favorable binding structure results in excellent paper cross profiles, particularly on gap formers.

Figure 1: Optiply/Optispeed structurally bound triple layer


Figure 2: Optiscope design with higher abrasion volume

According to Wangner, the product’s superior performance on all types of paper machines and for all paper grades resulting from the above fabric advantages leads to high productivity and higher efficiency.

Measurable added value
The Optiply family’s product manager, Oliver Baumann, gave a presentation that clearly explained how the design has made the value added measurable. He outlined how Wangner uses in-house measurement procedures and techniques that enable value added to be precisely calculated. The company recently introduced the Wangner Surface Analyzer (WSA), a modern surface measurement device that enables analysis and improvement of the topographical properties of both the fabric and the end-product, paper.

The heart of the new tool is a nano laser scanner that is used to scrutinize the fabric at a micrometer resolution level—layer by layer, mesh by mesh. An associated software application analyzes and visualizes the measured data. This spans from measuring the surface properties of new materials, material volumes, and mesh size over monoplanity on the running side of the fabric, right through to roughness measurements on paper surfaces. The fabric specialists base their design optimization on the results of the measurements. For example, they can improve drainage behavior of the fabric designs at higher speeds, which in turn enhances performance parameters such as formation, retention and dry content. The end result: paper producers benefit from higher daily production rates, which in the final analysis translate into money in their pockets.

A new surface treatment using the so-called Wangner Thermo Surface (WTS) process also produces measurable benefits. Instead of being ground, as was the case to date, the forming fabrics are now smoothed by means of a new thermal process that improves the fabric thickness, free volume and surface smoothness performance parameters, thereby significantly increasing running life and lowering power consumption. These enhancements give papermakers measurable optimization potential:

• better freedom from marking, thanks to a more even paper side
• no wet section adjustments necessary because the running behavior of the fabric is consistent throughout its entire running life
• lower energy use because of lower power consumption
• improved machine hygiene thanks to reduced fabric thickness and free volume.

The above examples demonstrate how developmental refinements in Wangner’s Optiply design focus on quality improvements that lead to quantifiable added value. The forming fabric specialists apply modern measurement techniques and fabric solutions and services that generate profits, as well as maintaining a close dialog with papermakers. This customer-oriented experience and information exchange contributes significantly to improving value added for both parties, as well maximizing their ability to penetrate their respective markets.