Single Vs. Double Carding Effects on Open-end Spinning & Yarn Properties

By: Jack Simpson

  • Double carding eliminated trash as a factor in open end spinning, it also improved open end spinning through better fibre separation of the feed sliver.
  •  When carding rate for single carded slivers was increased, rotor dust increased & yarn quality decreased on the open end machine without trash cleaner , but these effects were slight on the open end machine with trash cleaner.
  • For double carding , carding rate had little effect on open-end properties.
  •  The trash cleaner effectively eliminated the large particles [6 microns & above] that lodged in the fibre groove of the rotor, causing end breakage & yarn deterioration.
  • Double carding not only greatly reduced the amount of trash to the rotor [a ratio of about 60:1], but the average size of the particles was also reduced from 11 microns for single carding to approximately 6 microns for double carding.
  • Yarn strength of double carded slivers processed on the open end machine with the trash cleaner, undoubtedly a result of the better fibre separation from double carding.
  •  There was little difference in fibre orientation & weight per unit length uniformity between either the single or the double carded slivers.
  • Although fibre breakage was greater when the majority fibre hooks led into the opening roller, yarn properties, especially uniformity, were slightly better.
  • This is evidently due to the better fibre separation & distribution of the fibres to the rotor by the opening roller when the majority hooks are fed as leading.
  • The results of the study indicate:-.
    • Both ring & open end spinning require that fibres in the feed sliver be as parallel as possible, but for different reasons. For open end spinning, parallel feed fibres are required to minimize fibre breakage & to permit better fibre separation & distribution by the opening roller, whereas for ring spinning , parallel feed fibres insure good fibre control during apron & roll drafting. Fibre parallelisation, however, is more critical in ring than in open end spinning.
    • Trash is much more critical in open end spinning than in ring spinning.
    • Fibre separation in the feed sliver is more important in open end than in ring spinning. The ideal feed sliver for open end spinning is one whose fibres are straight, clean,& well separated. Determining the effect of variables on the weight per unit length uniformity of open end spun yarns with a capacitance type uniform tester is difficult because of the influence of the yarn bulk interacting with the influence of the real weight per unit length uniformity. Although 1-3/32 inches staple cotton is rather long for spinning a 12/1 yarns, the effects of double carding on a more practical, trashy 7/8 inches staple cotton would probably have been greater.


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