Research On The Super-large Drafting Device And Technology Of Ring Spinning Bidirectional Extension Aprons

The super-large draft of the ring spinning frame is the core of the high-efficiency spinning technology,and it is also an important support for realizing the weight of semi-products.Relevant researchers at home and abroad have carried out spinning research on the spun yarn advanced drafting device by increasing the number of additional components and drafting zones.There is still a problem of poor fiber control resulting in poor yarn formation.Based on the research of the predecessor's super-large drafting device,this paper intends to realize the super-large drafting of the spinning frame by increasing the draft ratio of the rear zone.The qualitative mechanism analysis of the drafting device and the research on the influence of the relevant process of the device on the spinning quality are carried out,which provides a certain theoretical basis and reference value for the research of the super-large drafting device.The specific research content of this paper is as follows:Firstly,the drafting device adopts the front zone forward extension apron drafting,the middle zone simple roller drafting,and the rear zone reverse extension apron drafting to achieve super large drafting.In addition,a four-roller coil spring cradle is designed for compression and the mechanism of the device is analyzed.Conclusions are drawn: 1)Under the control of the two-way stretch apron,the fiber shifting points are concentrated in the front and rear areas near the front and rear jaws,and the rear area has a larger draft ratio.It is conducive to the straightening of the fibers of the front hook;2)When the back zone aprons are reversely extended: the working side is in a "tight edge" state,which is beneficial to strengthen the control of the fiber and can improve the concave phenomenon of the upper apron;3)The rear zone adopts more when feeding a large amount of roving,the fiber layering can be improved;4)The whiskers fed by the super drafting device are scattered at the edges under the action of the rotating air flow,and the hairiness of the yarn is increased.5)Discrete event simulations were performed on the apron reverse drafting zone and the simple roller drafting zone,verifying that the shifting points in the apron reverse extension drafting zone are concentrated near the rear jaw.Secondly,a comparative study on the spinnability of the super drafting device and the ordinary drafting device.The results show that under the experimental design conditions,the super-large drafting device can achieve a maximum total drafting capacity of 145.23 times.Among them,the continuous spinning can reach 108.93 times and the spinning quality is good,while the general drafting device can reach 72.61 times.Compared with normal quantitative spinning with ordinary drafting device,super-large drafting device is suitable for spinning fine special yarn with heavy weight,and the yarn quality is better.In the super drafting device,the spinning quality is better with the draft distribution form of the larger draft multiple in the back zone,which also verifies the rationality of the super drafting device design.Thirdly,the influence of the rear draft ratio and the middle draft ratio of the super-large drafting device on the spinning quality is studied.Different raw materials and different quantitative rovings are used to spin yarns of different linear densities.The results show that as the draft ratio of the back zone increases,the quality of the yarn first increases and then decreases.An appropriate draft ratio is beneficial to the production.For the improvement of yarn quality,the draft ratio in the rear zone is about 2 times,and the spinning quality is better when the draft ratio in the middle zone is 1.14timesFinally,the orthogonal experimental design was used to optimize the process parameters of viscose roving spinning 16.8tex and 23.6tex yarns and cotton roving spinning 19.4tex and 23.3tex yarns on the super drafting device and verified by experiments.The optimal combination of process parameters obtained in the experiment are: rear zone draft ratio 2.4,middle zone draft ratio 1.14,spun yarn twist800t/m;rear zone draft ratio 1.8,middle zone draft ratio 1.14,spun yarn twist 750t/m;rear draft ratio 1.8,middle draft ratio 1.14,spun yarn twist 850t/m;rear draft ratio 1.8,middle draft ratio The multiplier is 1.14,and the spinning twist is 800t/m.