Major breakthroughs in spinning technology were on display at ATME-I 2000.
There have been several comments in the textile press that there is perhaps an excess of textile machinery shows and that machinery makers are limiting their efforts by electing to make a significant presence at selected exhibitions. This was clearly apparent at the American Textile Machinery Exhibition International (ATME-I) 2000, because the booths contained little equipment, and several manufacturers had only a token presence. While this report primarily focuses on staple spinning, it was clearly evident from the number of exhibitors, and from the activities at the various booths, that the nonwovens sector had become a major feature of this ATME-I (See the upcoming nonwovens report in the February issue of ATI). Exhibitors included companies that market cutting and recycling of waste fibers, opening and feed systems, web-forming systems, and different bonding techniques.A further surprising feature was the re-emergence and significant presence of Greenville, S.C.-based Saco Lowell Inc. at the textile machinery show. Indeed, Saco Lowell (and Fiber Controls) occupied the greatest amount of booth space of any single manufacturer at the show and, furthermore, actually showed the greatest range of spinning machinery. The focal point of the Saco Lowell display was the companys 766 Rovematic roving frame, which claimed to doff an entire 128-spindle frame in less than three minutes. Also on display were opening and cleaning machinery, the M-2000 card, the Model 995 draw frame, the Model 804 tdS spinning frame and Model 849 heavy ring twister. The brief review that follows looks primarily at general trends in yarn production and particular new developments viewed in the light of the last ITMA and OTEMAS. There have been several developments in carding machines, which, when taken together, could represent a major breakthrough. These include automatic measurement of sliver uniformity (all cards with autolevelers) and nep content (Truetzschler), automatic measurement of card settings (Truetzschler and Hollingsworth), centralized and possibly motorized flat setting (Truetzschler), automatic grinding of cylinder and flats (Rieter). If these technologies were combined, it should thus be possible to grind and set the card based on measurements of nep content and sliver uniformity. There have been few changes in drawing machines, but the possibility of integrating a drawing unit with the card is being promoted by Truetzschler. While this possibility has been previously proposed by other manufacturers, it is claimed that by using a higher draft, the present system gives improvements in fiber straightening and, hence, yarn properties. Truetzschler also exhibited its Sliver Focus System, which records the incidences of thick places (longer than 20 millimeters and 15 percent over-weight), and emphasized that sliver thick places can be correlated with yarn defects. One further drawing unit worthy of note was the Schlumberger chain gill with electronic autoleveling, which has a maximum speed of 500 meters per minute (m/min). SpinningRing Spinning In conventional ring spinning, a cotton spinning frame (with Murata link winding) was shown by Shanghai Erfangji Co., while Schlumberger showed a double-sided carpet-yarn machine with autodoffing and sliver stop motions operating with a draft of 73.Compact Spinning The buzz word in staple spinning at ITMA 99 was compact. While this term was originally used by Rieter to describe its technology adopted from Fehrers DrefRing development, Rieter replaced the terminology with comfort spinning and, ultimately, Com4. The technology is also termed condensed spinning by other manufacturers. The concept behind this spinning technology is that the strand of fibers issuing from the drafting system is condensed (usually pneumatically) and this gives the yarn a more compact structure (See Photograph 1-all photos and figures are at the bottom of the page).In compact spinning, the fibers are integrated more tightly into the yarn structure, resulting in yarns that are less hairy, stronger, more extensible and lustrous. Fabrics produced from the yarns are softer, stronger, have better abrasion resistance, and give better print and pattern definition. In terms of processing advantages it is claimed that fewer end breaks occur during spinning and, for certain end-uses, it is possible to reduce the spinning twist and thus increase production on the ring frame. In downstream processing, it is claimed that the reduced hairiness and increased strength give better performance in knitting and weaving. Indeed, because of the improved surface characteristics of the yarns, it is claimed that singeing, sizing and waxing can be eliminated. While four different systems of compact spinning namely, Suessen, MAL, Zinser and Rieter were shown at ITMA 99, three different systems were exhibited at ATME-I 2000: Rieter showed a new version of the Com4 system. The drafting system used is a double-apron system with two top front rollers. The bottom front roll of the drafting system is perforated, and as the drafted strand passes between the two top front rollers, the strand is condensed. The new system utilizes one suction roller for each roving (and each spindle), unlike the system shown at ITMA, which used shared drafting and suction roller for two rovings (See Photograph 2). The new system, which is designated ComforSpin K44, is not yet available, but it is intended for combed cotton yarns. Suessen exhibited the EliTe spinning system. Suessens implementation of compact spinning follows a different approach than Rieter, in that the EliTe system is an addition to an existing drafting unit. A perforated apron, through which suction is applied, is positioned after the bottom front roller of the drafting system (See Figure 1). An additional top roller, which is gear- driven from the top front drafting roller, forms a nip with the apron and drives it through friction. Because the additional top roll is slightly larger than the front roll, a small tension (draft) is applied in the condensing zone. The suction through the perforated apron is applied through a narrow angled slot in the tubular profile (the tube that supports the apron). This condenses the fiber strand and is claimed to cause the fiber assembly to rotate around its own axis so that the fiber ends are closely embedded into the fiber assembly (See Photograph 3). Suessen announced it can now retrofit the EliTe Spinning System to existing ring frames. A possible advantage of this system is that it is relatively easy to revert back to normal spinning with the removal of the perforated apron and the extra top roll. A further claimed advantage is that almost all short-staple fibers can be processed on the EliTe system (both carded and combed). Marzoli had a static demonstration of its Olfil system, which resembles the Suessen system in that it also uses a bottom perforated apron and an extra top front roller. The Olfil system is still under development and not yet commercially available. The major difference between these two systems is that, whereas Suessen utilizes a bottom perforated apron that extends back into the nip of the normal front roller, the Marzoli system uses a bottom roller around which the perforated apron passes. This implies that the Suessen system has greater control of the issuing strand. Indeed, a video of the Olfil system showed a lot of freedom for the fibers as they passed to the suction roller. An additional difference between Suessen and Marzoli is that, while they both use slightly different roller sizes to promote the tension in the condensing zone, Marzoli use a timing-belt drive, whereas Suessen uses a gear drive.One observation on compact spinning is that the improvement in yarn processing due to the higher strength and lower hairiness does carry a small penalty. The reduction in hairiness reduces the amount of air carried with the yarn, which can result in hotter running of the traveler, which shortens traveler life. It may thus be necessary to use slightly slower spindle speeds when operating compact spinning frames. A further interest is that Rieter has attempted to quantify a COM4 value, which is defined as: COM4-value = 100,000/(yarn twist * yarn hairiness) where twist is turns per meter (T/m) and hairiness is measured with UT3 or 4. Higher values represent compact yarns of better quality.Rotor Spinning There was little new in rotor spinning and indeed the only machine shown was a Schlafhorst Autocoro SE 8 machine, which had been modernized using Suessen upgrade components. The main feature of the conversion is the use of the SC 1-M spin box, which is claimed to offer improved fiber control during combing of the fiber beard, coupled with improved aerodynamics. The machine was also shown spinning Ne 20 yarn (50/50-percent polyester/cotton) at 116,000 revolutions per minute (revs/min) and 204 m/min. An additional feature of the conversion is the use of a new piecer carriage that no longer required the use of a starter yarn. It is evident that the modernization of rotor machines is currently an attractive alternative to purchasing new machines.Vortex Spinning Murata Vortex Spinning (MVS) (See Photograph 4) was initially unveiled at the OTEMAS exhibition. It has aroused a lot of interest because of the claimed possibility of spinning 100-percent cotton at high production speeds (maximum 400 m/min). The system is best viewed as a development of jet spinning, as available information indicates that the yarn produced is fasciated. It was interesting to note that while three machines were exhibited at OTEMAS, only one machine was shown at ITMA and ATME-I. The reasoning given was that, when shown earlier, the machinery was under development and different configurations were being used, whereas the configuration is now finalized. The MVS 851 machine shown at the exhibition was very impressive spinning 100-percent carded cotton into Ne30 yarn at 350 m/min. It is clear that this system offers major production advantages over other spinning systems (See Figure 2). Yarns and fabrics produced are regarded as ring-like (See Photograph 5), and there have been claims that, in some respects, they resemble combed cotton products. There are, however, significant fiber losses associated with this system, and while it has been claimed that most of the loss is short fiber, figures of fiber waste of 5 to 8 percent have been quoted. The system has undergone development in U.S. mills for several years, and significant quantities of yarn are being commercially produced. It was claimed that 200 machines are presently installed. Historically, successful spinning systems have doubled in production speed within eight years of their introduction. Based on this maxim, it would appear that the future looks exciting for MVS, but to realize the full potential of the system, significant developments in drafting and winding technology may be necessary. Areas Of Significant InterestConversations with exhibitors and representatives of the spinning industry indicated that there is significant interest in two areas of quality control the monitoring (and control) of moisture content and the detection and elimination of foreign materials. While these areas have for many years been regarded as very important to worsted and woolen spinners, their significance for cotton spinning is just being recognized. Moisture measurement and control is important with respect to both the ease of fiber processing (and hence, yarn quality) and the management of materials within the mill. Different sensors and approaches are offered by different manufacturers, but the main areas of measurement are the input and the final product. Systems for monitoring bales are available from, for example, Streat, Forte and Malcam. These units can monitor the moisture content of unopened bales. Fortes system uses harmless electromagnetic waves. Monitors placed on either side of the conveyor register the regain of the bale. Malcam utilizes microwaves and claims they not only measure average moisture content, but can also detect wet spots, hot spots and large foreign matter in the bale. These systems could also potentially be used for moving fiber webs. In this area, Mahlo offers a multifunctional web-scanning device, which can use either infrared or microwave moisture sensors (depending on the web characteristics). Additional sensors can be used for measurement of the thickness and weight of the webs. Single yarn packages can be assessed for moisture content using non-contact systems from Forte and Malcam. While the Forte system claims to be able to assess the moisture content of palletized yarn packages, Malcam prefers to sample individual packages. Foreign material detection and removal, including other unwanted debris, can be achieved at many stages of processing. Intuitively, the earlier in the processing stage the defect is removed, the better, because the impurity is coherent, and thus early removal prevents its spreading to a larger volume. Unfortunately, in order to remove the impurity, it has to be identified, which, in turn, requires that the fibers be at least partially opened. In general, the systems use a camera system to scan the fiber tufts (See Figure 3) and then eject unwanted material, usually with the assistance of jets of air (See Photograph 6). Systems working at the early stages of the opening line are available from Uster, Barco and Jossi. The Vision Shield Compact system offered by Jossi (marketed through Rieter), of which there are presently 350 installations, was shown to be capable of removing small tufts of colored fibers and small sections of film (about 2 inches by 2 inches). Truetzschlers new Securomat SCFO system works at the deduster stage, during which the fibers are well opened, and thus enables easier identification and removal of foreign materials. Optical sensing devices offer the potential of foreign material identification but not removal at the draw frame. The final stage of foreign material removal is at the clearing stage, which can be during winding of ring yarn and spinning of rotor, jet or vortex yarns. Uster and Loepfe (Barco) are well-known in this area, but other manufacturers of optical sensing devices could also enter this market. It was interesting to note that Loepfe has created a Foreign Fiber Standard, which is a table showing the classification for foreign fiber defects in yarns.The limitation of the current systems is that they rely on distinct color differences between the raw material and the foreign materials. Unfortunately, some of the foreign materials may be very similar to the normal fibers, and thus defects will not show until after coloration. ConclusionThere is no doubt that staple spinning is at the forefront of technology in terms of automation and productivity. In addition, there are greater possibilities for improving yarn quality by utilizing online and offline monitoring and control devices. However, it was evident at ATME-I that alternatives to staple spinning are also making significant strides that may ultimately lead to products that directly compete with those traditionally made from staple-spun yarns. Visitors to ATME-I must have noticed the considerable amount of activity associated with the use of air to twist, texture, intermingle, and cover filament yarns. There are also major breakthroughs taking place in nonwovens technology, with respect to both productivity and fabric properties.