The weak twist of the fine yarn means that the twist is lower than the normal value, the strength of the yarn is insufficient after the end of the fine yarn is broken, and the splicing is difficult. The short segment yarn is in a small twist state, which is commonly called weak twist.

1 category

1.1 Oneness: coarse details generated by uneven drafting. During the twisting process, the twist is concentrated to the details, the twist at the thick section is small, the strength is low, or the details are too long, forming a fragmentary twist coefficient and low strength. The long details caused by the roving cause insufficient twist during the yarn forming process and low strength.

1.2 Single-spindle: single-spindle failure, the entire yarn is thicker than normal, this type of yarn may be accompanied by rubbing the ring.

1.3 The whole set: process errors occur

       Judging from the actual production process, the weaker twists and weak single twists of the single spindle are the major influences. One weak twist cannot be connected to the head, the value of the lathe is large, and the entire single spindle is weakly twisted. It is not easy to be found and removed because of the large rubbing of the steel ring. It is the key task to control weak twist. The whole weak twist is not easy to occur, and it is easy to find, and generally does not cause negative effects.

2 Harm of weak twisted yarn

1.1 Powerful decline

1.2 produces yellow and white files. The contrast is more obvious after color absorption

1.3 Increase in repeated yarn ends

1.4 Easy to produce steel yarn

1.5 Knitting and weaving machine breakage increase

1.6 Weak twist easily produces hairiness

1.7 Weak twists easily get cotton balls (neps)

1.8 Use weakly twisted yarns as warp yarns. Due to the large amount of color absorption, a warp-like color warp will appear.

3 main factors of uneven twist

1.1 When the roving frame does not use a false twister, the twist of the spinning section is far lower than the process design twist, so that the normal roving elongation is also large (generally greater than about 2%). This is mainly due to the fact that the tip of the spindle is the sag point. The greater the friction effect at the tip of the spindle, the stronger the sag phenomenon of the sliver.

1.2 The fineness of the spun yarn is poor, especially the occurrence of thick knots and details has a greater impact on the twist unevenness of the yarn.

1.3 Uneven spindle speed is an important reason for uneven twist of the yarn. The uneven spindle speed is mainly caused by the difference between the rollers, the spindle condition and the slip ratio between the spindle belts. The main factors affecting the slip ratio are the tension of the spindle belt, the quality of the inner and outer layers of the spindle belt, the taper of the spindle tip and the spindle. Differences in disc diameter and lubrication conditions of the spindle.

1.4 Influence of the length of the ingot belt and the tension of the ingot belt on the ingot speed: If the ingot belt tension is large, the slip ratio between the ingot belt and the roller is small, and the slip ratio between the ingot belt and the ingot belt is also small, and the ingot speed is high. Therefore, the twist of the yarn is large. Conversely, the yarn twist is small.

       The influence of the length of the ingot belt on the tension of the ingot belt: if the length of the ingot belt is long, the tension of the ingot belt is small, and if the ingot belt is short, the tension of the ingot belt is large. If the length of the same spindle belt of the spinning frame and the twisting machine are not the same, it will cause a large difference in the tension of the spindle belt of the same spindle, resulting in the uneven spindle speed, which will affect the uneven twist of the yarn. Insufficient laps on the spindle belt, twisting and broken burrs, excessive adhesion of the flying belt on the spindle belt, inflexible rotation of the spindle and the spindle belt caused by the oil stain on the spindle, etc., will all cause uneven twist of the yarn. Have a degree of impact.

1.5 Poor contact between the spindle and the bobbin, the worn or irregular round inner hole on the top of the bobbin, the light weight, the bending of the spindle, and the unstable operation of the spindle, etc., will cause the tube yarn to jump or "invisible jump" during operation, Causes the rise of yarn twist unevenness.

1.6 Due to the lack of strong work responsibilities and the inadequate management of the workshop laboratory, the twist number of teeth is used incorrectly, resulting in a large number of strong and weak twisted yarns, that is, wrong twisted yarns.