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Yarn Doubling – types, objectives, and application

Two-For-One or TFO for strengthening and reducing unevenness of ring yarns

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Doubling reduces unevenness of single yarns and the strength of the doubled yarn is correspondingly better than the single yarns. In this article Ring Doubling, Two-For-One (TFO) twister, quality required by yarn to get best-doubled yarn are discussed.

Two-For-One (TFO) is a two-stage process where the yarns are doubled and then twisted. In TFO process two or more single yarns are twisted in order to enhance the properties of the end-products such as strengthening the yarns.

Generally, the wax is applied to yarns before the first twisting stage in order to reduce the friction on yarns.

Objectives of doubling

  • To increase the strength of the yarn
  • To increase smoothness, evenness, lusture, uniformity, and compactness of yarn.
  • To obtain the better deposition of a twist.

Doubling Applications

  • Jeans sewing thread
  • Type Cord
  • Cable yarn
  • Cutting yarn

Types of Doubling

  1. Ring Doubling

    The difference of ring doubling from the ring is:

    • No drafting
    • Creel in a system is different & creel contains yarn(No rove)
    • Roller combination is different

    Doubling Yarn is designated as follows:

    Ends up with 40 Count 2/40
    Ends up with 10 Count 3/10
  2. Two For One twister (TFO)

    Here yarn is transferred to a cone, then two ends yarns are combined (Doubled) and wound on a cone without twisting. Then the yarn is supplied to twister machine where the twist is applied in such a way that one revolution of rotating disc inserts two round of twist. The twisted yarn is then wound on a cone.

 Qualities of Single yarn to get best-Doubled yarn

  • The elongation of the yarn under lea strength tension should be uniform of the same count.
  • The twist should be uniform throughout
  • The breaking strength of yarn should not vary too much
  • 4% tolerance on either side should be allowed.

The formula for Double Yarn Count

Single yarn of the same count

Final count = Single yarn count
No. of doubling


  • Resultant count of component thread
    • Count: 1/N = 1/N1+1/N2 (N = Resultant counts, N1, N2= of same count yarn)
    • TPI of doubled yarn = TPI of single yarn (60-70%)
  1. Muhammad Naseer says

    How to double spun with polyester yarn

  2. Mehedi says

    Good job

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