Combing

For the video visual defect artifact, see Interlace. For the combing of hair, see Comb. For the torture method, see Combing (torture).
Noble comber in Bradford
French Comb PB31L for worsted system

Combing is a method for preparing carded fiber for spinning. Combing is divided into linear and circular combing. The Noble comb is an example of circular combing. The French comb is an example of linear combing. The process of combing is accompanied by gilling, a process of evening out carded or combed top making it suitable for spinning. Combing separates out short fibers by means of a rotating ring or rectilinear row of steel pins. The fibers in the 'top' it produces, have been straightened and lie parallel to each other. When combing wool, the discarded short fibers are called noils, and are ground up into shoddy.[1]

In general there are two main systems of preparing fiber for yarn: the worsted system and the woollen system. The worsted system is defined by the removal of short fibers by combing and top preparation by gilling. In the woollen system short fibers are retained, and it may or may not involve combing.

Description

The circular combs used have long metal teeth, and only barely resemble the comb used on hair. However, they are used in a similar fashion with one comb holding the fiber, which is slowly dubbed in by a brush, while the other is moved through, slowly transferring the fiber to the moving comb.[2]

The rectilinear comb uses a circular comb mounted on a drum to comb out the fringe and remove short fiber (set by a scale so fibers less than, for example, 25 mm are removed) not held by a clamping mechanism. The row of pins known as a top comb is a very fine tooth comb, for example 25 teeth per inch; it is inserted in cylindrical combed fringe to act as an impediment to contaminates (burr, seed etc.) flow. The top comb acts as an impediment to contamination moving into a combed sliver. On a next circular combing short finer and contaminates are removed. The circular combing without short fibers are placed on a moving belt in an overlapping motion. The circular combing and top comb insertion is repeated and combed fibers - now called tuft are overlapped. The overlapping produces some cohesion allowing the tuft then to be twisted to form a combed sliver. This sliver is weak and unsuitable for spinning. To allow spinning to take place additional gilling is required to introduce fiber end irregularity (Sokolov 1994).

Combing the fibers removes the short fibers and arranges the fiber in a flat bundle, with all the fibers going the same direction. This preparation is commonly used to spin a worsted yarn. Woollen yarns cannot be spun from fiber prepared with combs, instead the fiber must be carded. Cotton is combed when it is to be used for quality fabric with high thread counts.

In general, combing is done to filter or sieve out any short length fibers (for example, fibers shorter than 21 mm). Combing or carding is a primary process, followed by the gilling process, which removes hooks and involves three separate machines. Combing is then followed by two gillings to remove irregularity in the sliver and randomize fiber ends. This post-combing process is required if spinning is to follow. It is known that a sliver can be spun to a yarn of only 21 fibers with a suitable average length of 150 mm.[3]

Combing is a mechanical sieve, and so will not remove any containment with a form similar to the fiber being combed. Such contaminants must be mended out from a final garment. The manual mending out is a costly process.

There are two competing combing technologies: the Noble (1853) comb (variants Lister, Heilman (1846) and Holden) and the French comb. The Noble comb technology is inefficient, hence most combing in the world is carried out on the French system. The French system is superior as it combs the entire length of a fiber. Noble combs suffer from the problem that they will not comb 2 mm of a fiber's length. The 2 mm is the distance between counter-rotating pins. The French system is a rectilinear combing system as opposed to earlier woollen systems developed in England. Although the Heilman and Noble comb was an original circular design (also developed in min and 18–19th-century England) as it happens in modern history, English mills didn't share technology – resulting in development of superior technology on continental Europe in the mid-19th century, as in France.[4]

Efforts were made by Bradford to study the mechanism of noble combing but they failed to produce tangible results.[5] The Noble and French combs are now well understood technology thanks to work by CSIRO.[6] After 1994, Sokolov has endeavored to improve combing performance in the rectilinear comb. Combing technology continues to develop: Sokolov and Kirby developed a theory for combing model, simulation software for combing and drive design in 1982. Current technology used in providing comb drive by introducing innovation on cam performance to deliver textile fiber needs and separate mechanical performance of the comb was developed by Sokolov. The cam technology was an advance on century-old technology of cams by producing a subspecies of new cam design.

Machinery

In cotton manufacture, the Heilmann comber was superseded by the Naismith comber. In the worsted process a Noble comber was a common make, but now a French comber is more common.

The Noble comb is no longer used in worsted system as technology is inefficient. Noble combing may have uses for woollen system, or long fibers 250 mm+. The predominant technology for all fibers is the French comb system. A cotton comber is scaled and simplified mechanically version of a rectilinear comb relative to a mean fiber length (similar to Naismith comber). This scaled version of wool comb can be seen in stroke of the components used in a cotton comber. The scaled down has the purpose of accommodating fiber length and fiber physics requirements. The same scaled-up version of a comb can be seen in the way flax is combed.[7]


See also

References

  1. ↑ Dooley 1914, p. 40
  2. ↑ Collier 1970, p. 68
  3. ↑ CSIRO 1990.
  4. ↑ Happey, F., Contemporary Textile Engineering, 1982 ISBN 0-12-323750-5
  5. ↑ Dyson E and Happey 1960
  6. ↑ Sokolov and Kirby, CSIRO 1990-94
  7. ↑ Sokolov, Nick 2013

Bibliography

Wikimedia Commons has media related to Combing machines.

fiber

This article is issued from Wikipedia - version of the 6/11/2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.