How to improve yarn drop head retention in spinning process?
With the development of textile market, reducing the number of workers and reducing the labor intensity has become a sharp and urgent issue. In such a situation, it has become normal for new enterprises to choose collective doffing spinning frame. How to make good use of collective doffing device and improve the rate of spinning machine start-up retention is a problem that must be solved by equipment manufacturers and users.
A. Equipment
1 six centered
That is to say, the ring, spindle, guide hook, air ring, grabber and separator are at the same central point, which is also the basic requirement of spinning production.
2 adjustment of the position of the wire ring cleaner
As the name implies, the wire ring cleaner is to clean the accumulated flowers on the wire ring. In principle, the higher the count, the smaller the spacing. Taking 14.58 tex as an example, the interval was 1.8 mm. If the separation distance is too large, it will not only fail to clean the yarn, but also be easy to get out of the steel ring when dropping the yarn, increasing the start-up breakage; if the separation distance is too small, the steel ring will run unevenly or even stick, which may cause yarn loosening, weak twisting and breakage.
3 select the appropriate height of leaf plate
Generally, the distance from the starting position to the top of the tube is 20 mm to 25 mm. Matching with the selection of appropriate specification of steel wire ring, the yarn does not touch the separator plate when the yarn is small, and does not touch the bobbin head when the yarn is large.
4 steel ring plate leveling
The ring plate shall be at the same height, and the height of the ring shall be in the middle of the waste tray when the yarn is dropped.
5. Select the appropriate cycle of flat cleaning, car cleaning, steel ring replacement and tail yarn cleaning
a) Cycle of flat and wipe: the condition of the equipment is the basis of normal production. It is required to wipe the vehicle thoroughly every half a month, carry out part of the maintenance work every four months, do well in lubrication work and routine maintenance work. Each unit can make its own maintenance plan according to its accumulated experience.
b) Replacement cycle of steel wire ring: reasonable service cycle of steel wire ring has a great influence on the end breakage. The cycle is too long, the spinning channel is seriously worn, the light one scratches the yarn, resulting in the decline of strength, the details of yarn, and the serious one will produce neps. According to the spinning speed, production variety, spinning form, steel ring type and reasonable period explored by the manufacturer.
c) Period of tail yarn cleaning: the cleaning of tail yarn has a great influence on the retention rate of start-up, because the tail yarn will interfere with the operation of normal yarn during start-up, and constantly rub and strike the normal yarn, resulting in the increase of broken ends and the increase of yarn hairiness. Therefore, a reasonable cleaning period should be established.
6 working state of normal collective doffing device
Maintain the collective doffing device, ensure that the height, in and out, left and right positions of the air frame are normal, and the operation is in place.
B. Technology
1. Use reasonable spindle speed curve to ensure the retention rate before dropping
Jwf1562 spinning frame adopts 9-stage frequency conversion speed regulation setting, which can refine the spindle speed curve into three stages: first stage, small yarn stability stage, small yarn forming stage, medium yarn acceleration stage, medium yarn peak speed stage, medium yarn deceleration stage, large yarn deceleration stage, large yarn stability stage and spinning off speed stage. In the whole process of speed change, try to be stable, smooth speed curve, avoid sudden acceleration and premature deceleration, and maximize the unity of the contradiction between production and life.
2. Select suitable ring shape and weight of steel wire
According to the type of ring, the corresponding type of steel ring should be selected. The opening should not be too large, but the yarn must have sufficient channel. The principle of selecting the weight is that the yarn does not touch the separator when the yarn is small, and does not touch the bobbin head when the yarn is large.
3 body yarn
The yarn wound on the yarn body during yarn falling is called corset yarn. Based on 0.5-3 turns, the higher the count, the more turns, and vice versa.
4 tails
The safety yarn wound on the waste silk disc is called tail yarn. In principle, the less, the better. However, when pulling out the yarn, it should be ensured that the safety yarn cannot be pulled apart while the yarn is cut off.
5 braking time
It is more important to ensure that the spindle can stop suddenly in the braking time after rotating at a sufficient speed, so as to reduce the weak twist in the roller triangle area, especially ring spinning.
6 yarn positions
The lifting position of the steel ring plate in the falling yarn is called the lifting position. In principle, it should be higher than the yarn cutter to ensure that the yarn is easy to cut.
7 medium position
When driving, the highest position of the steel collar plate is called the middle yarn position. It is necessary to ensure that the down distance is enough to stretch the braided yarn, and that the yarn cannot be broken due to the long down distance. At the same time, it is necessary to take into account the winder reaction, and it is not difficult for the winder to unwind due to too much middle yarn.
8 spindle speed
The principle is not only to ensure that there is enough speed to open the air ring for timely twisting, but also not to break the yarn due to the excessive instantaneous tension caused by the high spindle speed, but also to pull the braided yarn apart with the speed of the lower steel collar plate.
C. Operation
1. The stopper shall ensure the retention rate before yarn dropping
Generally, we require no more than 5 pieces for the whole car. After yarn dropping and shutdown, we need to take out the air box flower in time to ensure that the air suction of whistle tube and the negative pressure of compact spinning are normal.
2 the doffer should follow up the doffer in time
Try to participate in the yarn dropping process as soon as possible, pick out the unqualified bobbin, remove and replace the bobbin that has not been removed completely, and clean the broken yarn at the yarn guide hook and flute nozzle, so as to shorten the yarn dropping time and drive in time.
