Combing
Combing is a method for preparing carded fiber for spinning. The combing is divided into linear and circular combing. Noble comb is an example of circular combing. 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 the 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 fibres are called noils, and are ground up into shoddy.[1]
In general there are two main system of preparing fibre for yarn. System are known as worsted and woollen system. Worsted system is defined by removal of short fibre by combing and top preparation by gilling. The other system referred to as woollen system short fibre retained, that system 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 fibre, which is slowelly dubbed in by a brush, while the other is moved through, slowly transferring the fibre to the moving comb.[2]
The rectilinear comb uses a circular comb mounted on a drum to comb out the fringe and remove short fibre ( set by a scale so fibres less than for example 25mm 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 25teeth 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 shot fibres are placed on a moving belt in an overlapping motion. The of 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 fibre end irregularity( Sokolov 1994 ).
Combing the fibres removes the short fibres and arranges the fibre in a flat bundle, with all the fibres going the same direction. This preparation is commonly used to spin a worsted yarn. Woollen yarns cannot be spun from fibre prepared with combs, instead the fibre 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 remove the short length fibres. For example fibre shorter than 21 mm. The comb is a filter or sieve for short fibre length and it defines the Worsted processing system. In process of combing carding is a primary process followed by 3 gilling machining. The gilling process is there to remove hooks and involves 3 separate machines. Combing removes short fibre content as sated earlier. The Combing is than followed by 2 gillings to remove irregularity in the sliver and randomize fibre ends. This post combing process is required if spinning is to follow. It is know that a sliver can be spun to a yarn of only 21 fibres with a suitable average length of 150mm.[3]
Combing is a mechanical sieve and will not remove any containment that looks like a fibre being combed. That has to be mended out from a final garment. The manual mending out is a costly process.
There are two competing combing technology - Noble (1853) Comb ( variants Lister, Heilman (1846) and Holden) and French Comb. The Noble comb technology is inefficient hence most combing in the world is carried out on French system. The French system is superior as it combs the entire length of a fibre. Noble combs suffer from the problem that they will not comb 2mm of a fibre length. The 2mm is distance between counter rotating pins. The French system is a rectilinear combing system as oppose to earlier woollen system developed in England. Although Heilman and Noble comb was 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 the continental Europe in mid 19th century- France.[4]
Efforts was made by Bradford to study the mechanism of noble combing but it failed to produce tangible results.[5] The Noble and French combs are now well understood technology thanks to work by CSIRO.[6] Post 1994, Sokolov has endeavoured to improve combing performance in rectilinear comb. Post 20th century effort in combing technology. Sokolov and Kirby developed a theory for combing model, simulation software for combing and drive design in 1982 ( Csiro provisional patent and papers related to combing ). Current technology used in providing comb drive by introducing innovation on cam performance to deliver textile fibre 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 sub species of new cam design.
Machinery
In cotton manufacture, the Heilmann comber was superseded by the Naismith comber. In worsted a Noble comber was a common make now its a French comb.
Noble comb is no longer used in worsted system as technology is inefficient. Noble comb may have uses for woollen system or long fibres 250mm+. Predominate technology for all fibres is a French Comb system. A cotton comber is scaled and simplified mechanically version of a rectilinear comb relative to a mean fibre 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 a purpose to accommodate fibre length and fibre physics needs. The same scale up version of a comb can be seen in way flax is combed.[7]
See also
References
Bibliography
- Collier, Ann M (1970), A Handbook of Textiles, Pergamon Press, p. 258, ISBN 978-0-08-018057-1
- Dooley, William H. (1914), Project Gutenberg Textiles (Project Gutenberg ed.), Boston, USA: D.C. Heath and Co., retrieved 13 November 2011
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