High Speed Spun Yarn Production | Rotor Spinning | Friction Spinning | Self twist Spinning |Twist less Spinning

Production of High Speed Spun Yarn:
Much research has been done to develop a spinning system for staple fibres that will shorten the yarn spinning by eliminating some of the steps of the conventional spinning. The research is oriented in simplifying the yarn manufacturing process and to produce yarns more economically. In these recent developments the conventional method is broken in between, for instance, the staple fibres may be directly made into yarn from carding or even directly from the blow room stage. These methods have their own advantages and limitations.

Some of the methods of producing the spun yarns by breaking the conventional method are as follows:
  1. Rotor spinning
  2. Friction spinning
  3. Self twist spinning
  4. Twist less spinning
1. Rotor Spinning (Open-end spinning): The spinning starts with the carded slivers, which are fed directly into the spinning operation. The roving and the twisting by ring are eliminated in this process. The steps in open-end spinning are as follows:
  • The card slivers from the carding stage are fed through rollers over a opening roller.
  • The opening roller breaks up the sliver.
  • The opened slivers are taken by an air stream and deposited on the inner surface of the rotor running at a high speed.
  • The fibres are drawn out from the rotor and as the fibres are drawn off, twist is inserted by the rotation of the rotor thus producing the yarn.
2. Friction spinning: Friction spinning is also identified as DREF spinning. This method of spinning is another type of open end spinning, which combines the rotor and air techniques. The steps in the production of the yarns with friction spinning are as follows:
  • The sliver is first separated into fibres through carding or combing rolls.
  • The air stream delivers the opened fibres to the two cylinders which moving in the same direction.
  • The movement of these cylinders helps in forming the fibres into yarns.
  • The alignment of the fibre is controlled by the angle through which the fibres are fed in between the cylinders. If the angle is small, the fibres would be more parallel.
3. Twistless spinning: This process of spinning involves the arrangement of fibres parallel to each other, adhering them together with the aid of a bonding agent and removal of the bonding agent after the yarns are constructed into fabrics. The twist less spinning eliminates the twisting process in manufacturing a yarn. The process of twistless spinning is as follows:
  • The roving is wetted and drawn out.
  • The drawn out slivers are sprayed with sizing (bonding agent) and then wound on packages.
  • The slivers with the bonding agent are steamed to bond together. These slivers are used in the fabric construction.
4. Self-twist spinning: This process of spinning involves inserting alternating S and Z twist in the fibre strands that come from the drafting system. This is done by passing the slivers between the draft rollers which rotate along the axes as they rotate to deliver the threads. The detailed explanation is given below:
  • Pairs of roving are fed onto the drafting rollers in such a way that the last set reciprocates axially.
  • The roving slivers are drawn out on succession of these drafting rollers. The action of the drafting rollers causes a rolling action of the strands as they emerge.
  • The side ways movement of the roller causes the stands to wrap around each other.
  • After the rollers complete their side ways motion in one direction, the movement is then shifted in the opposite direction.
  • The resultant yarn therefore has alternating sections of right and left hand twist.
For further illustration, you can refer to the archived VSAT lecture in the CD titled ‘Introduction to Yarn Craft’ having CD code number C0324, phase number 608, and class number 2.

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