Pulp and Paper Canada

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MACHINE CLOTHING


September 1, 2008
By Pulp & Paper Canada

As Canada’s pulp and paper industry seeks to redefine itself in new and uncharted market environments, it is critical that every step of the papermaking process makes the quality and efficiency grade….

As Canada’s pulp and paper industry seeks to redefine itself in new and uncharted market environments, it is critical that every step of the papermaking process makes the quality and efficiency grade. Machine clothing remains in constant contact with the paper surface throughout this process, and as such, plays an integral role in determining the integrity of the final product. Pulp & Paper Canada checked in with top paper machine clothing suppliers in order to place a finger firmly on the pulse of this important sector of the industry. Albany International, Weavexx, AstenJohnson, BWA Additives and FPInnovations-Paprican all weighed in with their perspectives on the latest developments in paper machine clothing, their upcoming projects, and how to keep an edge and stay ahead of the game in a rapidly changing industry.

PPC: What trends and developments are currently characterizing the paper machine clothing industry?

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Albany International: With paper consumption and operating rates down, the paper machine clothing industry must provide solutions for its customers. As suppliers, we have to understand our customers’ business drivers. Then, we have to provide the products and papermaking experience to improve our customers’ profitability. For instance, with oil prices at levels never seen before, energy costs are a huge burden on the paper industry. Therefore, products that can reduce energy usage are imperative to the profitability of a paper machine or mill.

AstenJohnson: The last 10 years have seen a dramatic increase in the number of Gap/Hybrid and Twin wire machines, with ever-changing configurations to enhance drainage and improve sheet properties. These changes have enabled the industry to address issues, such as faster machine speeds, lighter basis weights, environmental pressures (closed loops and recycled fibre), while increasing filler usage and refining for sheet quality. These technological advances have placed greater demands on the forming fabric to make a lighter, stronger and more uniform sheet at higher fibre efficiencies using shorter fibre lengths at higher drainage velocities under greater mechanical forces.

Weavexx: The global paper market continues to experience pressure from escalating raw materials and energy costs, and competition from other media, especially in the publication grades. Our technology and support efforts focus on helping our customers make the highest quality product at the lowest total cost per ton. Geographically, there is a shift in demand, and production into Asia has clearly changed the global picture in recent years.

Paprican: Some general trends currently characterizing the industry include the single-and double-layer forming fabrics being replaced by triple layer fabrics that provide better fibre support for improved retention, as well as good drainage and extended life. Forming fabrics could be seen as a tool to optimize fines and filler distribution in paper, while specific fabrics are designed for each forming section configuration. Single-layer bases of press fabrics are being replaced with multi- layered ones designed to minimize fabric imprint onto the paper, and irregular (stochastic) felt base has been designed and tested to replace or complement standard periodic woven bases. The stratified but of the press fabric contains very fine filaments to provide improved smoothness, and a completely new generation of press fabrics with improved water removal properties can be generated by the fabric construction and surface treatment methods. Additionally, press fabrics are now being designed and produced to perform optimally from the start, which would usually be obtained only after several hours of real production.

PPC: What projects is your company involved in, and what future paper machine clothing endeavours do you anticipate undertaking?

Paprican: We have completed the evaluation of forming fabrics for tissue products, and in the future we may develop new projects with paper machine clothing suppliers in the following areas:

• to use our computational model to predict the effect of clothing on paper surface and bulk structures

• to examine how felt/wire marks affect tension band linting

• to determine how paper machine clothing affects the surface and print quality of the new multi-layered sheets FPInnovations is developing.

AstenJohnson: We are using the concept of engineered drainage planes, which incorporate and harmonize all leading edge fabric performance knowledge and concepts to meet the many different applications (grades, speeds, machine configurations). This concept, along with polymer engineering, has led to two forming approaches to meet industry demands. The CenTec, which is 100 mesh, low caliper SSB triple layer, provides a fibre support index (FSI) of over 200 without sacrificing mechanical stability. The key to stability is a new engineered machine direction yarn. The design uses the established philosophy of increased FSI/support points to produce a better draining sheet with superior properties. WebTec is a Warp Integrated sheet Support Design forming fabric structure that is constructed by integrating all the machine direction yarns into both the top and bottom surfaces. A centre plane can be engineered to provide a controlled resistance to the very high impingement velocities found on the modern high-speed paper machines.

Albany International: Currently, we are working with a number of other suppliers, ranging from machine builders, chemical suppliers and educational institutions, on projects and products that will allow for lower costs in terms of reduced energy usage, downtime and waste, while removing machine limitations and improving sheet quality.

PPC: Do increases in chemical costs impact your business or product lines, meaning, if papermakers change the chemical composition used in their processes in order to reduce costs, do your own paper machine clothing products have to respond? If so, how?

Albany International: Absolutely. Chemicals are used on the paper machine in order to either improve paper quality or process runnability. Paper machine clothing is a key component in the papermaking process of forming, drying and conveying the sheet. This interaction of chemicals and machine clothing can either be very positive or detrimental to the papermaker. Collaborating with chemical suppliers has allowed us to prepare for new chemicals as they enter the market, and working with our customers when changing chemistry or processes allows us to use this knowledge and experience to minimize, if not eliminate, papermaking disruptions.

PPC: How have you responded to industry contraction?

Albany International: The paper industry in North America continues to remove excess capacity due to the drop in demand. With some grade reductions in the double-digit range, our focus remains on product line-focused plants in order to drive efficiency, technical development and consistency.

AstenJohnson: North American papermakers are seeing continued market shrinkage in printing and writing grades as reading habits change and computerization of information replaces paper. The high value of the Canadian dollar relative to the U. S. dollar has put extra pressure on Canadian producers who sell into the U. S. market. Each year there are less North American paper machines operating, resulting in reduced demand for paper machine clothing. We closed our forming plant in Warrendale, Pa and are in the process of closing our dryer plant in Walterboro, S. C. to align our capacity with the North American market. At the same time, construction of world-class machines in Asia continues at a rapid pace, and we are participating in this growing market both by shipping fabrics from North America and producing in our new facility in Suzhou, China. Papermaking in North America has gotten a lot tougher and this is reflected in our customers’ needs
for paper machine clothing and service. We’ve seen an increased emphasis on forming fabric designs that improve sheet properties and support the move to higher value grades as commodity markets erode. Our newest product, CenTec, was developed to provide improved formation, retention, and print smoothness on ground wood grades. It was first introduced in the Canadian market. More than ever, North American papermakers are looking for another set of experienced eyes to look over their machines to ensure best of class productivity.

PPC: How has a challenging and shifting market dynamic impacted the paper machine clothing process? Has a need for superior, high-grade products translated to changes in paper machine clothing?

Paprican: The changing market is forcing papermakers to improve product quality while controlling production cost. Although there are many tools papermakers can use to improve product quality, machine clothing is one area where we can improve product quality without process modification or capital investment. There has been tremendous development of paper machine clothing during recent decades. For example, while 20 years ago it was common to remove the press after just 10 days of operation, today a typical lifespan of the new generation of felts is about seven weeks, in spite of increased machine speeds and heavier nip loads. Machine clothing has become more specific to the requirements of the type of paper produced, as well as to the configuration of the paper machine. On the FPInnovations pilot paper machine, the clothing is changed on a regular basis to suit the needs of the trials. The use of seamed felts allows us to change the press fabrics in a very short period of time.

PPC: What kinds of patents have you generated? How large is your research and development team?

Weavexx: As part of Xerium Technologies’ global group of companies, (Weavexx, Stowe Woodward, Huyck. Wangner), our paper machine clothing R&D teams are located in North America, Europe and South America. Through a concerted effort, we have generated over 450 patents in paper machine clothing. The industry also licenses around 25 specific PMC technologies from our company.

PPC

* Jim Moloney, marketing manager for Albany International, Christine Beaulne, technical marketing specialist for BWA Additives, Bruce W. Janda, forming product business leader and forming global innovation leader, and Alan Cheverton, forming product manager of AstenJohnson, Steve Cole, director – PMC marketing for Weavexx and Martin Champoux, director of membership and communications for FPInnovations, Paprican contributed to this report.


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