Neps in the raw material can be classified as mechanical neps or biological neps. The unevenness and tensile properties are found to be best for flat speed 360 mm/min with significant increasing of waste percentage. A manageable average nep level in a bale is from 200 to 350 neps/g. But neps formation due to high cleaning intensity overweighs the effect of neps removing in card cylinder. linage analysis is being used to quantify white speck neps on dyed fabric. The carding process will always reduce neps. We perform these diagnostic tests in my company on routine basis, and the problem can either be caused in the spinning process or during knitting. The two main factors affecting nep formation are fiber characteristics and mechanical processing. Bhavdip Paldiya Dept. In order to study the effects of heat setting conditions on the properties of 100% cotton yarn, 30/1 Ne combed ring yarn cones were heat setting in a XORELLA CONTEXXOR (yarn conditioning and steaming system). The Ne24 and Ne30 cotton yarns have comparable unevenness and … In Indian cottons, the ratio of smaller size neps to larger size ones is about 55:45. The mechanical processes affecting neps formation include ginning, opening and blending, carding, combing, drawing and spinning. Nep removal efficiency in carding is determined using the following formula [100 × (neps in the chute-feed – Neps in the carded sliver)/neps in the chute feed]. The effect of contamination on final yarn quality and various techniques of contamination removal during spinning processes have also been discussed in detail. A spinners double in the warp or in yarn for circular knitting can downgrade hundreds of meters of woven , or knitted fabric. It was observed that yarn spun on the EliTe compact spinning frame have the following advantages when compared to those spun on the conventional spinning frame: higher tenacity and elongation at break, lower mass irregularity measured on short segments, and a significantly smaller number of faults such as thin & thick places and neps, as well as a higher degree of elasticity, and a … Further work could be done on producing quality yarn of various counts from other natural, synthetic and blends fibres to justify this analysis. Combed yarns are superior in quality when compared to carded yarn as they are generally finer, stronger, smoother and more uniform due to the removal of short fibers and the alignment of fibers. Effect Of Spinning On Yarn Quality - Sep 18, 2020 - The number of fiber roots extracted from the roving is the same whether the roving is of light weight or heavy weight in the drawing of the yarn. All cotton bales, manually harvested, mechanically harvested, saw-ginned, or roller-ginned will have fiber neps. The yarn quality tends to deteriorate i.e. Textile terms and definitions define a `Nep’ as a small knot of entangled fibers that usually comprises dead or immature fibers. There is an inverse nature of NEPS (200%/km) with the increase in polyester proportion in the blend, which is shown in Figure 4. The residual neps can be as low as 30 neps per gram in carded yarns and as low as 8 or 10 neps per gram in combed yarns. 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The mechanical processes affecting neps formation include ginning, opening and blending, carding, combing, drawing and spinning. This type of nep is very common, and it represents the majority of neps in U.S. cotton. This means that lower the neps in the card sliver could mean lower comber noil, which can be a major saving to spinners. The removal of neps represents a significant added-cost of yarn manufacturing since they may require more frequent wiring of carding machines, or higher comber noils during combing. Mechanical neps are those made up of only fibrous material containing at least five or more fibres. 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In this study, the relationship between fiber properties and yarn imperfections has been investigated using statistical and Monte Carlo techniques. However, these defects may also be due to the presence of fiber contaminants during the knitting process as a result of fly generation during knitting. A list of potential substitutes, if you can't get hold of (or can't afford) Rico Design Fashion Cotton Neps DK, with detailed advice and warnings about any differences. This is because the equipment required to gin, and clean cotton will inevitably result in some fiber entanglement causing neps to occur. 13. Question 1: What are neps, seedcoat neps, and white specks? They are mechanically created during harvesting and in the lint-cleaning process after ginning. Pvt. * CTF, SVKMs, NMIMS, MPSTME, Shirpur. Data from the Uster tester [ 1] suggest that average ring spinners produced nep levels in the range from 25 nep/km (≈ 0.3 nep/g) at about 6 s cotton count to 1300 nep/km (≈ 100 nep/g) at 45 s cotton count. The sensitivity levelwas 3for thick places and neps and - 50% for thin places. It is to be noted that neps below critical nep size will not influence yarn quality/fabric appearance significantly. Question 4: We receive frequent complaints of white specks and undyed spots in fabrics made from our yarns. Figure 4:Effect of polyester/cotton blend ratio on NEPS 200%/Km. Neps are associated with poor yarn and ultimately with poor fabric appearance and have an effect on yarn uniformity and dyeing quality. Neps in the raw material can be classified as mechanical neps or biological neps. The quality parameters such as unevenness (Um% and CVm%), imperfections/km (thick places/km, thin places/km and neps/km), yarn hairiness, yarn strength (count strength product), moisture% and yarn … Neps can generate at draw frame due to inferior quality of card sliver at the higher card production rate. Fig 4: Effect of fibre length on neps [2]. Fiber neps have always presented a challenge to mills and manufacturers. There are four stages of processing during spinning in which nep content can be controlled:  This is because different cards in the same line may have different nep removal efficiency because of the different wiring conditions of card machines. Neps do not generate after carding due to the number of draw frame passage. Effect of polyester/cotton blend ratio on NEPS 200%/ km. Pure fiber neps (or mechanical neps): these are neps consisting only of fibers entangled together. The author of this article is solely responsible for the content and the recommendations made. Effect of yarn winding Most of the mills use high-speed winding machines to wind the yarn. measures neps in yarns as short thick spots. The effect of neps on yarn cost is twofold: (1) neps must be largely removed before yarns can be produced, (2) residual neps can be detrimental to the appearance and the value of yarn. This type of nep appears as light or white spots in the finished fabric. Neps in the raw material can be classified as mechanical neps or biological neps. Biological neps are more serious than pure fiber neps because they are more difficult to disentangle, and they tend to be progressively fragmented into smaller and smaller neps during spinning preparation. What are the causes? In a mill using 100,000 bales annually for combed ring-spun yarn, a 1% to 2% less comber noil could mean a saving of about $1 million per year. This can be as low as 40% and as high as 90%. Mechanical neps are those made up of only fibrous material containing at least five or more fibers. If you have any query or want to publish article, please contact: textilelearners@gmail.com. Neps containing foreign material such as seed coat fragments, leaf or stem materials … Yiyun Cai et.al. Yarn produced from shorter fibers has negative 2 effect on yarn tenacity, hairiness and yarn imperfections. The occurrence of higher level of smaller size neps in Indian cottons affects yarn imperfections in fine and superfine counts. I’m working as a textile consualtant in several local and international companies. But at high cleaning intensity (fig.-2), higher cylinder speed shows poor yarn quality in case of neps (+280%). A third category of neps found on the surface of the dyed fabrics was named pancake type neps. YARN FAULTS Effect on Quality ( Cntd…) Faults like spinners doubles are difficult to determine in the yarn, with the naked eye. Seed Coat Neps Influence In Yarn Quality In a recent trial conducted by Zellweger Uster, it has been determined that fiber neps as measured by the Uster AFIS, contain two types of neps: mechanical neps and seed coat neps. Disclaimer:  This article responds to questions addressed by a number of spinners in Vietnam and Bangladesh regarding cotton fiber neps and seedcoat fragments. Normally, long and fine fibers are more flexible, and they have more tendency to curl and entangle together than short and coarse fibers. Modal is a regenerated man-made fibre and free from short fibres, neps, and impurities. COTTON USA SOLUTIONS® is a registration of Cotton Council International and has been registered by the United States Patent and Trademark Office. The combing process will always remove neps. There is an inverse nature of NEPS (200%/km) with the increase in polyester proportion in the blend, which is shown in Figure 4. An industry expert explains how the U.S. Cotton Trust Protocol can help you meet your goals. When high variation of neps between cards is observed, better card maintenance and wiring schedule will be required. AIM OF THE PROJECT To compare different blend ratio of Polyester/Cotton yarn in terms of yarn quality parameters such as CVm% and Um%, Thick, Thin, Neps, IPI, CSP, Hairiness, Single yarn strength by which we can find out the best quality blended yarn of 30/s Ne. Carding both generates and removes neps. The yarn neps reduces with increase of crimps. If you continue to use this site we will assume that you are happy with it. The author welcomes any additional questions on the subject and he will be happy to answer them. Yarn imperfection (neps, thick and thin places) on the other hand is an important yarn parameter which affects yarn and fabric processing, and quality parameter. Carding is the most significant process where significant decrease in the level of neps can take place. Card clothing is the core component of the carding process to increase the yield and quality and reduce the nep. Further work could be done on producing quality yarn of various counts from other natural, synthetic and blends fibres to justify this analysis. On the other hand, they can produce quite fatal results in the finished product. It should also be noted that the higher the carding speed the lower the nep removal efficiency. Notify me of follow-up comments by email. By continuing to use this site, you agree to the use of cookies and our Privacy Policy.You may provide personal information, such as your email address, to us via this website. Email:- kiranpk.rp.kp@gmail.com, prafullkolte@gmail.com. In this study, the relationship between fiber properties and yarn imperfections has been investigated using … The yarn tenacity improves at lower card production rate because of better carding quality (Rakshit et al, 1985).Neps in the drawn sliver mainly increase due to inferior carding quality at higher card production rate. Neps in the Combing Process For quality jute fabrics or composites, good quality yarn is one of the basic needs. Jute fiber processing requires inter fiber cohesion which can be imparted by crimping process [5] , [6] , [7] . Neps of large sizes (> 2,000 µm) that manage to survive into the yarn can result in poor yarn appearance and they can appear in the finished fabrics in the form of undyed dark dots (white specks) particularly if they constitute dead or immature fibers. Effect of polyester/cotton blend ratio on NEPS 200%/ km Figure 4: Effect of polyester/cotton blend ratio on NEPS 200%/Km. Figure 4:Effect of polyester/cotton blend ratio on NEPS 200%/Km. Discover these answers and more. Can they be controlled? the condition in which the axis of a fiber departs from a straight line and follows a simple or a complex or an irregular wavy path. 11. 3.1 Neps (USTER ® AFIS-N ... describe the quality of a fiber or a yarn. Abstract Yarn testing plays a crucial role in gauging product quality, assuring regulatory compliance and assessing the performance of textile materials. Periodic and quasi periodic irregularities in yarn result in warp way streaks and weft bars in woven fabrics and a non-periodical yarn irregularity gives cloudiness in the woven or knitted fabric, leading to fabric rejections. Please direct your questions to the author at yelmogahzy@gmail.com. Neps not only adversely affect the appearance of cotton yarns and fabric but are also usually associated with lower yarn strength, ends down in … Neps are small knots of tangled fibers which are created during harvesting, ginning, and yarn manufacturing phases of production. S.P.Mishra, (2005); Fiber Science and technology; New age international ltd publishers. More than 80% of U.S. cotton fall in this range. The key step to control neps in the cotton mix is to purchase cotton bales that do not exceed 400 neps per gram, or 35 seedcoat neps per gram. Hence, to improve quality of these yarns, measures to eliminate smaller size neps during processing assume significance. Hairiness: Hairiness is measured using Uster Tester-4. [Show full abstract] to observe the effect of spinning parameters such as rotor diameter and speed on thick, thin places and neps of yarn in rotor spinning process. The study revealed a relationship between the blend ratio and the NEPS 200% in the yarn per km. It is important for spinners to diagnose the fabric defect very carefully before making a conclusion about the cause. thick, thin places and neps were increased when the rotor diameter increases from 43 to 54 mm. The main object of this work is to produce better quality yarn. Question 3: How can we control the effects of neps during spinning? Neps are associated with poor yarn and ultimately with poor fabric appearance and have an effect on yarn uniformity and dyeing quality. Normally, fibers of micronaire value above 3.8 are very mature. Light dense pure fiber neps may be straightened during carding particularly at low carding speeds. So neps of rotor yarn had been increased with increasing cylinder speed at high cleaning intensity. thick, thin places and neps were increased when the rotor diameter increases from 43 to 54 mm. In today’s climate, designers don’t just have an opportunity to create beautiful products, they have an obligation to use their informed positions to create innovative fibers, fabrics, design systems, and products that protect our planet. In this article, expert Dr. Yehia Elmogahzy answers frequently asked questions about the effect of neps on the manufacturing process. The latter have been determined to cause yarn faults This is because neps may either be removed during carding or straightened in the carding zone. It was also found a good correlation exists between the card web neps and the yarn neps. White speck neps contain minature clusters of fibers and are often not visible as defects until dyeing, rendering the fabric unsuitable for colornercial use, resulting in large financial losses.   Mechanical neps are those made up of only fibrous material containing at least five or more fibres. This is a long subject that I will be glad to discuss with individual spinning mills. In case some of these bales are available in the inventory, they can either be processed separately using slower rates of processing, or they can be dispersed in small amounts over many cotton mixes. And what causes them? The quality cotton yarn was produce by using rotor spinning system that can be used for weaving and knitting fabrics. Effect of flat speed of carding machine on the carded sliver and yarn quality Mohammad Mamunur Rashid, KZM Abdul Motaleb and Ayub Nabi Khan Abstract Processing parameters play an important role in influencing the quality of the final product in any kinds of production.