Fiber length is also one of the three most important fiber characteristics. It influences:
- spinning limit;
- yarn strength;
- yarn evenness;
- handle of the product;
- luster of the product;
- yarn hairiness;
- productivity.
Productivity is influenced via:
- the end-breakage rate;
- the quantity of waste;
- the required turns of twist (which affects the handle);
- general spinning conditions.
It can be assumed that fi bers of under 4-5 mm will be lost in processing (as waste and fly), fibers up to about 12-15 mm do not contribute much to strength but only to fullness of the yarn, and only those fibers above these lengths produce the other positive characteristics in the yarn. It is not only the condition at purchase that is important in assessment of fiber length; still more decisive is the length after carding. Processing conditions at the card, and also the fiber characteristics, must be such that the fibers survive carding without noticeable shortening. Where there is a high proportion of immature fibers, this will not be the case.