1. Dref spinning

This process belongs to open end group because the fiber strand (Drawframe sliver) must be opened completely to individual fibers and reassembled to a new strand (yarn). In Dref 2 spinning one or two carded slivers after leaving from drafting arrangement are passed to the main opening roller (a drum clothed with saw teeth). While the drafting arrangement creates only a light drafting effect, the sawtooth roller opens the strand to individual fibers. The separated fibers are lifted off the roller by a blower and form cloud, descending towards two perforated drums. One suction stream per drum draws the fibers into the convergent region. The newly arriving fibers contact the rotating yarn and are thereby caught and twisted. This process is primarily suited for the production of coarser yarns and recycled yarns.

In Dref 5 individualized fibers from a single sliver are fed through a closed or partly open fiber duct into the spinning nip at a acute angle to the yarn axis, so that they are stretched as far as possible when fed into the nip. Good quality of yarns in count range of 16s-40s Ne is possible with speed of 200 m/min.

In Dref 2000 friction machine the rotating carding drum opening the slivers into single fibers and a specially designed inlet system used for sliver retention. The fibers are stripped from the carding drum by a centrifugal force and carried into the nip of the two perforated spinning drums. The fibers are subsequently twisted by mechanical friction on the surface of the drums, which rotate in the same direction. S & Z twist can be produced without mechanical alteration in the machine. Dref 2000 friction spinning machines are utilised for the recycling textile wastes as well as the spinning of technical and other yarns.

The Dref 3000 friction spinning machine, the latest model of the machine is utilised especially for the production of multi-component yarns (hybrid yams) The applications of Dref spun yarns are: Blankets for the hometex range and military uses, as well as for hotels, hospitals, camping plaids etc.; Secondary carpet backing for tufted carpets and filler yarns for carpet wefts; Filter cartridges for liquid filtration; Canvas for the military and civil sectors -Asbestos substitutes (e.g. heavy protective clothing and gloves, gaskets, packings, clutch- and brake linings, flame retardant fabrics etc.); Filler yarns for the cable, packaging, shoe and carpet industries; High-tenacity, core yarns for ropes, transport and conveyor belts; High tenacity fire resistant protective clothing ; Composites for the aviation, automotive and engineering industries etc.

source : Express textile