Tekstil Teknik Dergisi Tekstil Haberleri, Tekstil Sektörü, Tekstil Teknik
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The most important quality parameter in texturing is the correct yarn tension. Abnormal tension levels and peaks result in dyeing problems. During production many problems can accumulate, which are not easily recognised. Without process tension control, these faults are usually only detected later in the fabric.
A tension control offers many options for obtaining a clear overview of production and quality situations at any time. The increased quality demanded for textured yarns, the use of new materials and of microfilaments, together with an increase in texturing speeds, requires quality controls that are more and more extensive. The quality control procedures, which are sometimes very labour intensive, can be substantially reduced by using on-line process monitoring, e.g. by measuring yarn tension continuously. In the case of Win-OLT, Retech has developed a yarn tension measuring system that continuously monitors yarn tension, records yarn breaks, calculates downtimes and provides machine efficiency and quality data. Retech AG originally invented this system in the early 1980’s thereafter distributed in most countries in partnership with TEMCO until 2009. Subsequently Retech AG itself approached the worldwide market very successfully to the satisfaction of the customers. Retech AG provides the OLT sensor itself as a standard product as well as the entire Win-OLT system. The measuring principle of the Retech sensors is based on the Hall effect. A spring with a small magnet is deflected as a result of changes in the yarn tension that occur during process. This causes a different magnetic field in the Hall sensor, which in turn changes the output signal ( 0-10 volt . ) Minimum long –term drift, maintenance free and easily to repair are advantages of this measuring principle and the sensors are in addition to this unaffected by spin finish, yarn residues or snow. After the input of all process parameters and the start of production, WinOLT monitors the yarn tension at every position 50 times per second. If the number of pre-defined faults is exceeded, it will be clearly recorded in the table and indicated both by the sensor LED and a bright alarm indicator located on top of the cabinet. If a machine has been fitted with a quality level yarn-cutting device, WinOLT will then, when requested, cut the yarn for these instances. If there are unknown problems with machine positions, WinOLT offers a graphical option to find the origin of the fault.
The advantages of a continuously controlled tension cannot be dismissed at all.100 % quality control during production is only one aspect. Also waste can be substantially reduced due to the early detection and as a matter of course is the software and the hardware extremely user-friendly with a wide range of facilities for fault detection by application of user defined parameters. The analysis of production data and the recording of yarn tension at all position enables long-term analysis. The evaluations of OLT data can be extended up to 75 doff. In this way faulty positions within each machine become obvious. Trend line for yarn breaks, quality or tension can predict problems that are just developing, and with this means preventive actions can be started in time. The new evaluation program developed by Retech AG at this times, will show more flexibility and will be even more operator friendly. Newly the evaluation of the data can be chosen arbitrary of a time period.
More than one day can be selected. In General the analysis will give an overview of efficiency information and shifts. That means that the customer can filter data and compare these data of every shift related to machine efficiency and product quality. The qualities will be classified in quality A, B C and newly also in a best quality A with not even one event. The take up overview will be amended with more important production information to ensure a perfect analysis of every doff and every shift.
This new evaluation system guarantees a perfect quality classification and an impeccable error analysis. The customer will be able to react early and an early pay pack is assured. The Win-OLT system consists of a sensor for various tension ranges ( 0-60 cN, 0-120 cN, 0-240 cN and specialities ), microprocessor with yarn cutters and doffing sub-units and a central control cabinet with computer system and printer together with the Windows based OLT- software in various languages. Retech AG is able to provide you an individual solution for different kind of production units. The system fits new machines as well as older types and a good team of engineers will elaborate the perfect solution for the existing machines. Retech AG has the experience in the application of its Win OLT system in many different industrial machines. Not only false twist texturing machines are predestined, also air texturing machines can be equipped, where the small Retech sensor fits perfectly and the online monitoring can be achieved easily. However texturing is not the only use for this system. It is also suitable for monitoring the yarn tension in other textile processes. Examples of this are spinning, winding, covering and draw twisting, among others. Also in the BCF process the Retech sensor can be found and works to the customer’s satisfaction. Quality control in many kinds of textile processes means Win-OLT: The industry standard for high quality and optimised production.
