Wool quality assessment

WOOL QUALITY ASSESSMENT

Purpose : The potential range of end products that wool may be used for is dictated by many qualities, including fineness, clean wool yield, length, color, and uniformity. Fineness, or grade, is of primary importance in determining market value of raw wool. Finer (smaller diameter) wools usually are associated with more expensive, lighter weight fabrics, while coarser-fibered wools (larger diameter) usually are used in bulkier sweaters, blankets, and carpets.

Skirting : Skirting is done after shearing and prior to judging of the quality of the wool. It involves removal of the objectionable parts such as tags, leg pieces, face, neck pieces, bellies, locks and stained portions from the body of the fleece. In addition, any applied colour or pigmented wool should be taken out and kept separately. Similarly, heavy burry wool found below the jaw should be picked. This will help the farmer in realizing a better price for his wool.

Parameters of judging wool quality :-

1. Fineness/Grade : In general, grade refers to the average diameter or thickness of the fibers. Three systems of wool grading are commonly used : the American or Blood system; the English or Spinning Count system; and the Micron system. The American Blood Grade System was developed in the early 1800s and originally represented the amount of fine-wool Merino genetics (Spanish origin) present in the native coarse-wool sheep. The English system of grading wool uses a measurement called the “spinning count” and is based on the number of “hanks” of yarn which could be spun from one pound of clean wool on the equipment available at the time the system was developed. Increased emphasis on an exact and highly descriptive method of describing wool grade has produced a measuring system in which individual fibers are accurately measured. The unit of measure is the micron.

Traditionally, the standard method of measuring these fibers is by a microprojection technique in which short longitudinal sections of the fibers are projected onto a screen at 500-fold magnification. Technological advancements like electro-optical and image analysis machines have greatly improved the efficiency and accuracy of fiber diameter measurement.

All three systems are measures of average fiber diameter and can be used interchangeably as shown in the table below, but the micron system is the system used internationally and preferred by wool buyers and manufacturers.