1. Several situations of weak twist 1. Oneness: Thick details caused by uneven drafting,During the twisting process, the twist is concentrated in the details, and the twist is small and the strength is low at the thick places, or the details are too long, resulting in a fragmented twist coefficient and low strength. The long details caused by roving result in insufficient twisting and low strength during the yarn forming process.
2. Entire single ingot：Single spindle failure, the whole yarn is thicker than normal yarn, this type of yarn may be accompanied by friction on the steel ring.
3.The entire unit：Processing errors.
From the actual production process, the biggest impact is the weak twist in one place and the weak twist in the entire ingot. The weak twist in one place cannot be connected to the end, which is a big problem for the lathe. The weak twist in the entire ingot will not cause the problem. The forming of large-rubbed steel rings is difficult to detect and remove, which is the key task to control weak twist. Weak twist is not easy to occur in the entire machine, and is easy to detect, and generally does not cause negative effects.
2.Dangers of weakly twisted yarn 1 strong drop;
2 produces yellow and white. The contrast is more obvious after color absorption;
3 repeated yarn breaks increase;
4 It is easy to produce grinding steel ring yarn;
5 End breaks on knitting and woven machines increase;
6Weak twist is prone to hairiness;
7 Weak twist is prone to cotton balls (neps);
8 use Yarns with weak twists are used as warp yarns. Since they absorb more colors, they will produce long warps in the warp direction.
3.Main factors for uneven twist 1.When the roving frame does not use a false twister, the twist in the spinning section is far lower than the process design twist, so that the elongation of the normally spun roving is alsoLarger (generally greater than about 2%). This is mainly because the top of the spindle flyer is the twisting point. The greater the friction at the top of the spindle flyer, the stronger the twisting phenomenon of the yarn sliver.
2.The evenness of the spun yarn is poor, especially the coarse yarn The occurrence of knots and details has a greater impact on the twist unevenness of the yarn.
3.Uneven spindle speed is an important reason for uneven twist in yarn. Uneven spindle speed is mainly caused by the difference in slippery rate between rollers, spindle conditions and spindle discs. The main factors affecting the slippage rate are the tension of the spindle belt, the quality of the inner and outer layers of the spindle belt, the difference between the taper of the spindle tip and the diameter of the spindle disc, and the lubrication conditions of the spindle.
4. Strap length and strap tension Impact on speed：If the tension of the spindle belt is large, the slippage rate between the spindle belt and the roller plate will be small.The slippage between the yarns is also small, and the spindle speed is high, so the twist of the yarn is large. On the contrary, the yarn twist is small.
The influence of spindle belt length on spindle belt tension：The longer the spindle tape is, the smaller the tension on the spindle tape is, and the shorter the spindle tape is, the greater the tension on the spindle tape is. If the lengths of the spinning frames and twisting machines on the same machine are inconsistent, it will cause different parts of the spindle belt on the same machine. There is a large difference in tension between the spindle belts, resulting in the same spindle speed Unevenness will affect the uneven twist of the yarn, resulting in poor spindle tape head, twisted and damaged burrs, excessive adhesion of the spindle tape, oil stains on the spindle, etc., resulting in inflexible rotation of the spindle and the spindle tape disc. etc., will have a certain impact on the twist unevenness of the yarn.
5.Poor contact between the spindle and the bobbin, the inner hole at the top of the bobbin is worn or not rounded, the weight is too light, the spindle rod is bent and the spindle is unstable, etc., which will cause the bobbin to run The middle jumper or ‘invisible jumper’ causes the yarn twist unevenness to rise.
6.Due to a weak sense of work responsibility and lax management of the workshop laboratory, the wrong number of twist conversion teeth was used, resulting in a large number of strong and weak twisted yarns, that is, wrongly twisted yarns.
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