The ring spinning machine is prone to post-roller torsional vibration when processing certain chemical fibers, which is more harmful to the yarn quality. Taking R14.8tex yarn as an example, when torsional vibration occurs, the sliver CV value increases from 11.51% to 12.29%, and the sliver CVb rises from 1.8% to 2.4%, and frequent yarn defects increase. The performance test index gradually deteriorates from the front to the rear.
Roller will feel a throbbing or high-frequency hemp feeling after touching the rear of the car. In severe cases, the roving entry at the rear of the car will measure intermittent jitters. When he touches the roller slightly, he will be frustrated once every two or three minutes. Roller torsional vibration is concealed, sometimes not in high temperature and high humidity season, sometimes light and heavy. After analysis, the torsional vibration of the roller is mainly caused by the acceleration torque of the roving whisker acting on the rear roller. Due to the high speed of the roving sliver in the middle jaw, the roving that is not fully untwisted will transfer the fast turning torque to the rear roller. The fast turning torque is gradually superimposed from the tail to the front of the car, forcing the rear roller to accelerate, and the rear roller is subject to the drive system's inability to accelerate. The fast turning torque is too large, which will cause the rear roller to rebound instantly to remove the fast turning torque. The torsional motion creates torsional vibration.
During the processing of certain chemical fibers, due to the large frictional cohesive force of the fiber, the draft force in the rear region is greatly increased, and the fast turning torque transmitted through the roving is enhanced, which greatly increases the probability of roller torsional vibration. In addition, if slipping occurs in the connection of the rollers of the roller section, the roller speed may also intermittently change under the drafting force of the roving. After a lot of experiments, we summarized the following technical measures to eliminate the torsional vibration of the rollers for reference.
1
Reduce roving twist. The roving has a large twist, strong fiber cohesion, and a large draft force in the rear zone. The acceleration torque transmitted to the rear roller increases, and it is easy to induce torsional vibration. This method is more effective to eliminate slight roller torsional vibration.
2
The rear rubber roller with smaller diameter and lower hardness is used. When spinning R14.2tex yarn, the rear rubber roller adopts 876 type rubber roller with a diameter of 28mm and a hardness of 73 to 75 degrees, and severe torsional vibration occurs; when using a 975 type rubber roller with a diameter of 26mm and the same hardness, it still has Obvious torsional vibration; after using a 965 rubber roller with a diameter of 26mm and a hardness of 63 to 65 degrees, the torsional vibration is eliminated. The reason is that the small-diameter, low-hardness rear rubber roller reduces the peak gripping force of the rear jaw, stabilizes the drafting force, and thereby eliminates torsional vibration.
3
Reduce the draft in the back zone. When spinning R14.2tex yarn, the draft in the back zone is 1.15 times, and there is severe torsional vibration. The draft in the rear area is reduced to 1.07 times, and the torsional vibration is eliminated. The reason is that the drafting force is increased before the critical drafting multiple is reached, and then the drafting ratio is increased in the subsequent zone. The drafting multiple in the rear zone is reduced, the drafting force is relaxed, the fast turning torque is weakened, and the rear roller twist is eliminated. Zhen.
4
Increase the back roller distance. Spinning JC / R14.7tex yarn, there is torsional vibration when the roller spacing is 17mm × 43mm. After the separation is enlarged to 17mm × 53mm, the torsional vibration is eliminated. According to the drafting principle, the smaller the gap, the stronger the control effect of the rear jaw, the larger the drafting force, the faster the turning torque transmitted to the rear roller through the roving will be, and it will easily cause the rear roller torsional vibration. Therefore, increasing the roller distance in the rear zone helps to reduce the drafting force, weakens the fast turning torque of the sliver to the roller, and achieves the purpose of eliminating the rear roller torsional vibration.
5
In response to the torsional vibration caused by the sliding wire of the roller connecting section, loosen each section of the roller and eliminate the bad roller to eliminate it.
