Fiber configuration in sliver and the incidence of hooks in sliver and rovings have been studied, employing two different techniques. It has been established that during the drafting of sliver at draw frames, trailing hooks are removed preferentially as com pared to leading hooks. The direction of presentation of hooks in the ingoing material (sliver or roving) at the ring frame has been shown to have a considerable effect on yarn strength and evenness. For best results with carded yarn, the majority of hooks in the feed to the ring frame should be presented to the drafting system in a trailing direction, i.e., there should be an odd number of processes between carding and spinning.

Hook formation at fiber ends and fiber disorder in the card sliver have been studied by using a fluorescent-tracer-fiber technique and Lindsley's method for measuring comb ing ratio. The rate of throughput at the card and the cylinder and doffer loadings have been shown to affect the proportions of the different types of hooks in the sliver. Other factors, such as the type of wire on cylinder and doffer, the action of flats, and the doffer comb speed, have been seen to have no influence on hook formation. Within the range of speeds investigated, the speed ratio between doffer and cylinder has little influence on hook formation. On the basis of the results obtained and the different hypotheses of Morton, it is suggested that the trailing and leading hooks are both formed at the junc tion of cylinder and doffer, but by different mechanisms.

167 first integral desorption result in the formation of certain number of points of contact between polymer chains where adsorption of water vapor cannot take place. When the same samples are rehumidified and desorption is made effective through small steps of interval desorption, there is little possibility of the formation of the same number of points of contact as were formed during the previous desorption. That the changes in the accessibility of the polymers is not due to any breaking up of the crystalline regions is indicated by the fact that no changes in density were observed after integral or interval sorption and desorption. , Dear Stir :After the initial work of Morton and Summers [2] on the formation of hooks in fibers at carding, some studies were undertaken in this laboratory to investigate the mechanism of hook formation at the card.These have been reported in a separate communication [3]. Another aspect of the same problem is the relationship between the fiber configuration in the material fed at the card and that in the outcoming sliver. Such a study is of particular interest to workers who are engaged in investigating methods to prevent the formation of hooks totally or partially at the card. In the study now being reported, the laps fed to the card were specially prepared so as to have different degrees and types of fiber disorder, and the characteristics of the delivered sliver were examined.On a 37-in.-width SACM card, equipped with flexible wire fillet, a blow room lap (410 g/m) of an Indian cotton Digvijay (Baer Sorter mean length: 22.3 mm; fineness : 1.44 pg/cm ) was carded at 3.6 kg/hr. A part of the outcoming card sliver (A) was converted directly into sliver laps, and four such sliver laps were fed to the card again. These laps were of two types: (B) in which the trailing hooks of the parent card sliver were fed as trailing to the card and (C) in which the card sliver trailing hooks were fed as leading. The r maining parent card sliver was combed, extracting 1 c;{ noil. The combed sliver (G) was converted into s iver laps and fed to the card in three different ways: fi st ( D) the fibers were aligned to the direction of feed, secondly (E) they were perpendicular to the direction of feed, and finally (F) they were in a disordered state of orientation with reference to the direction of feed. The sliver laps were cut into several 36in.-long pieces and then fed transversely for the feed of type 1 E ) . The conditions for feed (F) were obtained by breaking up the sliver laps into small tufts, from which laps of one square yard were prepared by hand. In all cases the rate of feed was maintained at 3.6 kg,,'hr.The fluorescent-tracer-fiber technique 13] was used for counting hooks in the card sliver. The fiber extent of each tracer was also determined. This is a measure of the effective length of the fiber as it lies in the web and takes into account the shortening in length due to crimp, hooks, etc. The trailing and leading ends of fibers were designated with reference to the direction of ...

The effect of the fiber configuration in the feed to the comber on the waste extracted has been investigated at different step-gauge settings and with different cottons. Experi ments have been conducted with normal combing and with combing without the top comb. With normal combing, the waste decreases with decreasing fiber disorder, and at a given fiber disorder it generally decreases with a reduction in the number of trailing hooks fed. However, with a high degree of fiber disorder in the feed. the waste tends to increase with a decrease in the number of trailing hooks fed to the comber. Without the top comb, the comber almost always extracts more waste when leading hooks predominate in the lap, irrespective of the fiber disorder. These results have been critically examined. and a hypothesis has been formulated with respect to the mechanism of waste removal at combers, to explain the observed facts.

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