October and November were busy months for harvesting in what is, of course, one of the world's largest cotton-producing countries. Each of the ten major grower states in India has its own specialised cotton variety: for example Punjab is famed for its J34 quality, ideal for coarse-count yarns; while Gujarat focuses on Shankar S6 variety, perfect for medium count; and Andhra on MCU, preferred for finer counts. In all these cases, and others, the issue of contamination presents real challenges.
Raw material
Next September again an army of pickers will bring in the new crop. This is when the vital first steps in quality control begin, as a sizable percentage of India's cotton gins rely on USTER's High Volume Instrument (HVI®) to classify the raw material. The system's precision quality measurement is the basis for objective standards in cotton trading - allowing market prices to be set at fair levels for both producers and buyers. That is why USTER®HVI 1000 is recognised by growers, ginners and traders worldwide as a dependable and impartial quality arbiter.
After purchase, the spinning mills pick up the task of controlling quality throughout the yarn-making sequence, starting with the incoming raw material. Here also there is a key role for the USTER® HVI 1000 - which has already provided accurate information on the raw cotton via its classification facility. Spinners thus have a detailed quality inventory of the cotton they have in stock. And this means they can select and manage bale laydowns, using HVI® data, to ensure that exactly the right cotton is chosen to produce the required yarn quality as economically as possible.
Obviously, the raw material mix is fundamental to achieving targeted yarn quality, but there are a number of additional process stages where yarn quality can - and should - be checked and optimised. The opening-line-card-combing operations are the first of these.
Continuing control
For all the processes before spinning, the USTER® AFIS PRO 2 single fibre test instrument is a massive help in defining and controlling blowroom, carding, combing and roving machinery settings to minimise waste.
In parallel, the world-renowned USTER® TESTER 5 is essential equipment for the mill laboratory, and its role in process optimisation and quality control is increasingly important. Its advanced sensors measure quality parameters such as unevenness, hairiness, diameter variations, count, foreign matter, imperfections, and remaining dust and trash particles. This test data is then used to facilitate optimum machine set-up and track spinning machine performance.
Total final monitoring
Even with ideal preparation and accurate spinning set-up, based on the USTER®instruments already mentioned, there is still a final stage which is required for serious quality assurance. Yarn clearing, based on latest-generation fault detection, is the only way to guarantee consistent quality throughout the entire yarn lot. Monitoring of the total output, in-process on the winding machine, is the solution. USTER®QUANTUM 3 yarn clearers are uniquely able to harness the power of sensor technologies - capacitive or optical with foreign matter - to identify and remove unacceptable defects before they get to the finished yarn package.
USTER® QUANTUM 3 displays the full YARN BODYTM of the running yarn. This on-screen visualisation shows the yarn profile, with its set tolerable variations. Smart Clearing TechnologyTM integrated with USTER® QUANTUM 3 then provides rapid analysis and proposes an ideal clearing regime for each article and quality requirement - at the push of a single button and without the need for highly-qualified personnel. Knowing exactly how many cuts are needed for a given quality target allows the spinning manager to easily define the optimum limit with minimum waste. Consistent quality is therefore assured.
Indian cotton's challenges
Where contamination of raw cotton is a potential headache, as in many varieties grown in India, the USTER®QUANTUM 3 has effective tools to ease the pain for spinners. Its new foreign matter sensor can detect all coloured foreign fibres and - crucially - separate these from vegetable matter, which is normally regarded as non-disturbing. The brand new polypropylene clearing option, with technological improvements can efficiently eliminate white and transparent polypropylene fibres.
Fabric quality with Total Testing
Spinners know only too well the cost of delivering defective yarn packages to the fabric producers: expensive claims, loss of customer confidence and damaged reputation will all ultimately impact on profits, if fabric faults are traced back to quality exceptions in the yarn, as most can be.
World-class quality control today requires quality monitoring of every single metre of yarn, as part of an overall awareness of the needs of the entire fibre-to-fabric chain. This approach is at the heart of the USTER Total Testing approach, designed to encourage and empower spinners to assure optimum quality consistently while considering waste and productivity.
The Uster Group is the leading high-technology instrument manufacturer of products for quality measurement and certification for the textile industry. The Group provides testing and monitoring instruments, systems and services that allow optimisation of quality through each individual stage of textile production. This includes raw textile fibres, such as cotton or wool; all staple fibre and filament yarns, as well as downstream services to the final finished fabric. The Uster Group provides benchmarks that are a basis for the trading of textile products at assured levels of quality across global markets. The Group's aim is to forward know-how on quality, productivity and cost to the textile industry.
The Group is headquartered in Uster, Switzerland and operates through a worldwide Market Organisation complemented by Technology Centres. It has sales and service subsidiaries in the major textile markets and Technology Centres in Uster (Switzerland), Knoxville (USA) and Suzhou (China). www.uster.com
(Uster Technologies AG, Sonnenbergstrasse 10, CH - 8610 Uster/Switzerland. Tel: +41 43 366 38 80. Mobile: +41 79 916 02 91. Email: edith.aepli@uster.com.)
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