Paper machine clothing - press felts, dryer and forming fabrics - are precision wear parts. With every machine pass they run across grooved rolls, through press nips, and are continuously loaded with water, fibres and process chemistry. The edges are especially critical: shear forces, redirections and guide elements cause the first fatigue cracks here. Without effective edge protection, the service life of the clothing drops dramatically.
The Problem: Edge Wear Limits Service Life
The edge and guide zones of paper machine clothing look harmless at first glance but are the weak point of the system. When fibres fray, microcracks form or the edge swells, the entire felt or wire becomes unusable - even if the central area is still perfectly intact. For paper mills this means unplanned downtime, premature replacement cycles and significant cost.
The BKT Solution: Flexonal® Edge Coating Applied Directly to the Clothing
For decades BKT Germany has developed PU systems under the Flexonal® brand, formulated specifically for this application. The coating is applied with mobile, precisely controlled Bachmann dosing units - typically at the clothing manufacturer or on-site at the paper machine. Flexonal® recipes are wear-resistant, permanently elastic and resistant to swelling in the aqueous process medium. Shore hardness, elastic modulus and bond strength to the fabric are tuned to the clothing type and machine position.
The Result: Noticeably Longer Service Life
A correctly designed edge reinforcement reduces edge fatigue, prevents fraying and keeps the clothing on its defined track. This significantly extends usable runtime in continuous operation and makes change cycles predictable. At the same time, the clothing stays dimensionally stable - important for uniform dewatering and consistent paper quality.
Why Material and Equipment Must Be Matched
Swapping only the PU material or only the application equipment rarely solves the problem: processing temperature, pot life, application rate and cure behaviour are tightly coupled. At BKT both sides come from a single source - the Flexonal® recipe and the Bachmann dosing unit are tuned together to the specific clothing type and machine environment. That reduces complexity on the customer side and ensures reproducible results over many years.