Friction (DREF) Spinning is a textile technology that allows very heavy count yarns and technical core-wrapped yarns to be manufactured. The technology was developed by Dr. Ernst Fehrer. Amongst the spinning systems, Friction spinning provides a good platform for production of core spun yarns due its spinning principle. Dr. Ernst Fehrer invented and patented the DREF friction spinning, in the year 1973, and named the system after himself. DR. Ernst Fehrer DREF. The friction spinning was based on the principle of open-end spinning, because the fiber strand must opened completely to individual fiber and then assembled to a new strand (yarn).
Friction spun yarns (DREF) yarns have bulky appearance (100-140% bulkier than the ring yarns).The twist is non uniform and found with loopy yarn surface. In friction spun yarns with high % age of core, stiffness is high, are usually weak as compared to other yarns. The yarns possess only 60% of the tenacity of ring-spun yarns and about 90% of OE yarn. The increment in twist and wrapping of the sheath over the core improve the cohesion between the core and sheath and within the sheath. The breaking elongation ring, rotor and friction spun yarns are found to be equal. Relative tenacity efficiency is improved during processing of cotton on rotor and friction spinning as compared to ring spinning system.