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Yarns
Published in Michael Hann, Textile Design, 2020
Drawing (or drafting) is the attenuation of a sliver, achieved through rollers moving more quickly at the front (the output end) of a machine compared to the back (the input end). Following the idea that thick and thin patches will often coincide when different slivers are simply placed one on top of the other, doubling is aimed at achieving a more regular sliver. As noted previously (in section 3.2), the term ‘doubling’ can be used also to refer to the action associated with combining two or more yarns into one twisted structure. In the context of slivers, doubling is often combined with drafting. So, if four slivers (each roughly equal in terms of weight per unit length) are fed into a machine (known as a draw frame) with input rollers turning at a speed equal to, say, x metres per minute and the output rollers (or similar arrangements) are turning at, say, 4x metres per minute (thus, considered to have a draft of 4) and within the machine the four slivers are brought together one on top of the other, then the resultant single output sliver will be broadly the same weight per unit length as each of the input slivers but will be more regular. Therefore, in this case, doubling and drawing have served the purpose of regularity and attenuation, respectively.
Textile Yarns
Published in Sheraz Ahmad, Abher Rasheed, Ali Afzal, Faheem Ahmad, Advanced Textile Testing Techniques, 2017
Khurram Shehzad Akhtar, Fiaz Hussain, Faheem Ahmad, Sheraz Ahmad, Abher Rasheed, Ali Afzal
On the base of the USTER Classimate, yarn faults are classified into the following categories, most of which can be removed with the help of any yarn clearer in the auto cone department during the winding process.NepsShort thickLong thick or double yarnLong thinNormally neps have a length of 0.1–1 cm and a diameter of about +420%. A short thick place appears as a very small fault and covers the length of 1–4 cm with a diameter range of +150% to +400%. Long thick places have a diameter range of about +50% to +200% with a length of 8–38 cm. Double yarn is also produced by doubling the material at any stage during yarn manufacturing as a doubling of roving or sliver. This fault is known as a double yarn. A long thin place and a long single yarn are also produced. A long single yarn is the yarn whose diameter is half of the main yarn. The cross-section of the thin yarn is –30%, –45%, and –75%.
Investigation of the concurrent sliver-opening mechanism and unveiling features of the new dual-feed rotor spinning concept
Published in The Journal of The Textile Institute, 2019
Nicholus Tayari Akankwasa, Huiting Lin, Jun Wang
The dual-feed rotor spinning concept is a new technique in open-end spinning designed to achieve effective fiber opening and blending through integrated dual feed and fiber transfer (Wang et al., 2014). Previous works on the dual-feed have projected tangible benefits of the dual-feed invention in the yarn manufacture (Akankwasa, Lin, Zhang, & Wang, 2016; Hajilari, Eskandarnejad, Behzadan, Moghadam, & Moghadam, 2007; Peyravi, Eskandarnejad, & Moghadam, 2014; Wang et al., 2014). With the dual-feed rotor spinning system, blend yarn production does not require doubling which is rather tedious and comes with extra costs. Slivers are directly blended by simultaneously feeding them on the dual-feed machine where they are carded and transported separately then assorted in the rotor within a single unit. Hajilari et al. (2007) and Peyravi et al. (2014) performed experiments on the dual-feed technique which attained yarns with enhanced fiber orientation, high tenacity, extension, work of rupture, strain at peak and hairiness compared to the conventional rotor spun yarns. Akankwasa et al. (2016) and Akankwasa, Lin, and Wang (2017) have presented recent studies on the dual-feed rotor spinning unit. Their studies revealed the suitable operating parameters to produce a dual-feed yarn, in addition to considerable characterization of internal airflow field of the dual-feed and conventional rotor spinning. Precedent commendations of the dual-feed rotor spinning unit by these studies prompt further interest in exploring the concept.
Cotton mule spinning after Richard Roberts
Published in The International Journal for the History of Engineering & Technology, 2022
Twiners were another type of mule-like machines used for doubling. Doubling is the process of forming a folded yarn by twisting together two or more single yarns. This is a distinct process from spinning and no drafting is involved. There were two types of mule-like machines used for this purpose known as French twiners and Yorkshire twiners respectively. French twiners worked in the same way as a mule, the moveable carriage carrying the spindles with stationary creel for the single yarn. Yorkshire twiners worked the other way, the moveable carriage carrying the single yarn.