ABSTRACT
As the removal of short fibres is the basic object of the combing process, the cylinder needles which mainly carry out this function, assume great importance. In conventional combers where the lap weights processed were limited, the needles did a very fine job of removing the short fibres quite efficiently. In fact, the idea of using needle combs is much older than the invention of the machine. It is known that since ancient times, people, especially ladies at home, were using needle combs for combing their hair. At the palaces of Rajas and Maharajas, combs with beautiful designs were used. The function, however, was the same whether the comb was ordinary or decorated – to comb the hair. In households, combs with two different densities are not uncommon, the initial coarser portion to remove the entanglements and the subsequent finer portion to straighten out, parallelise and smoothen the hair.
The comber machine has adopted the principle in toto. The only difference is that whereas, a single comb is used by women or men, there are a series of needle rows used in the comber machine. The principle of using initially widely spaced needles in the beginning rows and steadily increasing the needle population as the rows progress, is however, accepted as a general guideline for preparing the needling segment. Even initial little penetration to prepare the hair before straightening and a little deeper penetration to carry out a tough combing job is also followed by some needling manufacturers.
In short, whichever is the arrangement, it should serve the basic object: 1. it should fulfil the job of satisfactorily removing the short fibres and 2. it should not damage both the needles and the fibres as well. The effect of efficient removal of short fibres can be seen immediately by improvement in the web quality and later by an increase in the yarn properties, especially the yarn strength. As against cylinder needles, the top comb needling is simple, though can not be undermined. This is because, first, it is a single row of needles and second, there is a wide range of needle densities over which, the results are not much affected. Also, needles of different cross-sections are available. In practice, round and flat wires are two popular sections.
Lastly, whether cylinder needles or top needles, their maintenance is very important. The damaged or bent wires are very likely to spoil their performance in carrying out the assigned job. At every opportunity, their up-keeping has to be checked.
