What is Staple Fibre Yarns ? Spinning Methods of Staple Fibre Yarns ?

Staple-fiber yarn:

A staple-spun yarn is a linear assembly of fibers, usually joined together by twist insertion to form a continuous fibrous strand that is small in cross-section but of a fixed length. It is used to make cloth using popular processes like knitting, weaving and sewing. The actual strength or quality and appearance of both yarn and fabric handles will depend on the way the fibers are combined in the yarn process (Erich, 1987; Klein, 1995). The fiber used to spin this yarn can be natural or man-made. Man-made staple-fiber yarn is made using staple fibers cut from continuous filaments prior to spinning while synthetic fibers are made. Staple-fiber yarns can be further subdivided and classified based on the length of the staple fiber, the spinning method used for production, and the type and nature of yarn construction. Each of these categories can be further subdivided.

Staple-spun yarn can also be classified as short staple or long staple based on the length of the main fiber used in spinning. A staple fiber can have a staple length of about 10 to 500 mm. Short staple fiber by definition has a maximum length of 60 mm (cotton fiber is a short staple fiber with a staple length of about 25-45 mm). By conventional definition, long staple fibers have a staple length greater than 60 mm (wool fiber is a long staple fiber of about 60-150 mm).

Spinning method :

Currently, a variety of spinning methods/techniques are available for yarn production including ring-spun, rotor-spun, twist-less, wrap-spun and core-spun yarns.

Ring-spun Yarn:

It is the most widely used method of producing staple-fiber yarn. The fibers are twisted helically around each other to strengthen the yarn with spindles, rings and travelers.

Rotor-spun yarn:

They are similar to ring-spun yarns and are usually made from short staple fibers. The rotor is the most important twisting element in this spinning technique and is based on the open-end spinning principle. The rotor spinning method produces more regular and smoother, though weaker, yarn than ring spinning.

Twisted Yarn:

The fibers are held together by some chemical based adhesive, not by twisting, and are often laid on a continuous filament core.

Wrapping Yarn:

These yarns are made using staple fibers wrapped by another yarn, usually a continuous man-made filament yarn. Basically, this yarn is made up of two components i.e. warp yarn (as the outer material) and staple fibers as the inner material of the yarn. Yarns can be made from short or long staple fibers that form the core and filament yarns are wound in a helical formation on a continuous basis for the entire length of the yarn.

Core-spun Yarn:

Core-spun yarns have a central core (which is usually a filament yarn) that is helically wrapped with staple fibers and are produced in a single operation during spinning. It basically consists of two components. For example, a simple core spun yarn might have a cotton sheath (outer material) for handle and comfort, with a filament (often polyester) core (inner material) for added strength; or cotton over an elastomeric core. It is the converse of rap spun yarn with the elements changing positions with respect to each other.