Uster Shares Insights To Avoid Claims, From The Start Of The Process

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Uster Shares Insights To Avoid Claims, From The Start Of The Process

Producing consistent yarn quality is an everyday challenge, and a very difficult one. Detailed knowledge and understanding of the fibre raw material is absolutely critical to achieving the best possible quality in the yarn. To help spinners, Uster experts have put together guidelines for avoiding yarn irregularity claims, in a special edition of the Uster News Bulletin.

Drawing on decades of industry data, Uster notes that the root causes of yarn claims have remained largely unchanged over the past 20–30 years. While their intensity and distribution vary by end use, the primary triggers are consistent and identifiable. By analysing these factors and outlining clear pathways to operational excellence, Uster News Bulletin No. 52 serves as a focused, actionable tool for mills determined to reduce quality claims and strengthen spinning performance.

Laydown consistency – use data correctly

One factor which greatly impacts on the spinnability of cotton fibres, as well as the yarn quality, is fibre fineness. Cotton has inherent natural variations, so fibre fineness (micronaire) is therefore the most important parameter to be controlled within required limits.

Optimal bale mixing aims at a consistently narrow micronaire range. Minimizing variation in micronaire values, both across and within laydowns, is critical. Fluctuating micronaire values can lead to barré or inconsistencies in yarn strength, causing quality claims. To reduce the risk, spinners use data from Uster HVI for laydown management. Taking it further, many mills have integrated automated solutions such as Uster FibreQ, with algorithms that control not only micronaire but also multiple other fibre characteristics. This reduces manual work, but more importantly improves long-term quality from fibre to yarn by refining raw material selection.

Fibre process control – look closely at the blowroom

Uster’s experience shows that the reduction of neps is another of the most frequent challenges for spinning mills. Here, it’s better to avoid creating neps at the beginning of the process, instead of trying to reduce them in spinning. Many spinners take steps in the blowroom and carding processes to tackle this issue.

In the blowroom it’s about managing trash reduction, and preventing the increase of short fibre content and neps. During cotton processing, the material is opened into tufts, with several stages of opening and cleaning aimed at removing impurities. But a side effect of these processes can be an increase in neps and short fibre content, due to the mechanical stresses. Some spinning mills adjust card settings or try to remove broken fibres during combing, but a more effective and economical solution is thorough testing and blowroom optimisation.

To control blowroom and carding performance, measurements with Uster AFIS are part of the routine test plan, as well as also being applied after machine maintenance or changes in cotton laydown recipes. These tests ensure optimal opening and cleaning at an appropriate waste level. Close monitoring of potential fibre damage is essential.

Processing statistics – track fibre characteristics

The processing charts in Uster Statistics track the fibre quality characteristics. Key parameters for neps, short fibres, and impurities are plotted through each processing stage. The accompanying graphic shows the typical increase in neps in the blowroom from bale to card mat, followed by a decrease after carding as neps are removed. Spinning mills can compare their own levels against the global standard. This allows a quick assessment of the situation, identifying areas of overperformance or potential improvements.

Various raw materials – one common goal

Process control is also important, and even more so when processing mechanically recycled cotton. Depending on the source of the recycled material and its opening method, the short fibre content might already be at a naturally higher level when entering the blowroom.

Similarly, fibre damage can apply to man-made fibres which initially have uniform cut lengths. Uster AFIS 6 is able to measure cotton as well as synthetic materials. With thorough quality management, spinners can identify fibre deterioration at source, before it results in yarn irregularity.

It’s clear that fibre characteristics significantly affect both spinnability and yarn quality consistency. Therefore, understanding fibre quality and how fibres are treated during the spinning process is essential right from the start. What is not measured, cannot be controlled! However, this is only one element to be managed to avoid quality claims.

Uster has the technology, the experience and the knowledge to foster a new level of consistency in yarn production.

The company’s know-how is freely shared in Uster News Bulletin No. 52, which includes more chapters offering ‘best practice’ advice – from spinners for spinners – on how to take control of quality claims.

It’s clear that fibre characteristics significantly affect both spinnability and yarn quality consistency. Therefore, understanding fibre quality and how fibres are treated during the spinning process is essential right from the start. What is not measured, cannot be controlled! However, this is only one element to be managed to avoid quality claims. Uster has the technology, the experience and the knowledge to foster a new level of consistency in yarn production.

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