Mechanical Web Formation Processes

Mechanical web formation uses traditional textile machines such as roller or flat cards. But in contrast to yarn production, the fiber web produced is not formed into a sliver. 

The fibers are evenly opened and mixed by the fiber preparation. They are supplied via the automatic hopper-feeder or volumetric tower feeder to the actual web-forming machines, the roller card or flat card. 

Today s roller cards, developed especially for nonwoven production, make it possible to form randomly oriented nonwovens with randomizers. They counter-rotate with high speed in the direction opposite that of the main drum and by this transport one part of the randomized fibers to the next stage. High-performance, ran- 

The operating principle of worker and stripper is shown in Fig. 6.10. The fibers are taken off the main drum (A, tambour) by the worker (B) and parallelized. The worker passes the fibers on to the stripper (C), which transfers them back onto the main drum (A). Fibers can thus pass a worker several times before finally moving on to the next worker-stripper pair. 

With special roller cards for nonwovens production, random webs can be produced. Rollers that rotate at high speed in the opposite direction of the main drum take up the fibers. This results in a random orientation of the fibers. In most cases, two take-up rollers (doffers) are used. The machine is then called a two-doffer card (Fig. 6.11). 

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