Sliver
Also searched as: card sliver, drawn sliver, fiber strand
An untwisted strand of fibers prepared for further processing.
In detail
A sliver is a continuous, largely untwisted strand made from many individual fibers. It is an intermediate form that makes a loose fiber mass easier to handle, combine and draw during preparation for spinning. Its continuity does not imply that its constituent fibers are continuous filaments.
The science and numbers
Most of what happens to sliver is drafting. Draft is the ratio of delivery to feed surface speed and, ignoring waste, equals input linear density divided by output linear density. At the drawframe several slivers are fed together while being drafted, a doubling that averages out thick and thin places and straightens fibers. The nip spacing is set somewhat longer than the longest fibers so no fiber is gripped by both nips at once. From there, ring spinning needs a roving stage, typically with a draft of roughly 6 to 15, whereas rotor spinning feeds drawn sliver straight to the spinning unit. On the worsted route, pinned gill boxes control long wool fibers during drafting, and the fineness of combed wool sliver is measured by airflow under IWTO-6. Evenness is reported as the coefficient of mass variation and counts of thick places, thin places and neps.
A practical example
A card may deliver a strand of short cotton fibers as sliver. Later operations can combine or draw such strands before yarn formation. Imagine overlapping short pieces arranged into a continuous ribbon: the ribbon is continuous even though each piece ends.
What to distinguish
Sliver and finished yarn should not be used interchangeably. A sliver has not acquired the same structure or handling strength as the yarn ultimately made from it. Specify the processing stage when discussing a sample.
Origins and history
Roller drafting was the central idea of the mechanized spinning machines of eighteenth-century England, replacing the hand spinner's fingers drawing fibers from a distaff. The older verb draw survives in the names drawframe and drawing, while technicians use draft for the numerical ratio. Sliver is the continuous strand those machines were built to handle, carried between stages in cans and, for wool, formed into top.
Related terms
Sources & further reading
- CottonWorks: Sliver
- Woolmark: Wool processing
- ScienceDirect Topics: Roller drafting
- Woolwise (University of New England): Drafting and gilling of fibrous assemblies
- Textile Learner: Draft, draft constant and production calculation of drawframe
- SGS Wool Testing Services: Airflow, OFDA and Laserscan (Info Bulletin 3.3B)
Technical references reviewed 2026-09-22. Examples are illustrative. Industry organizations and manufacturers describe their own fields; their references are not independent product endorsements. Figures are approximate and depend on the stated test conditions.