The drawing process is responsible for the tasks of merging, drafting, mixing, and sliver formation. It has the function of improving uneven long segments of cotton slivers and improving fiber hooks. However, some problems often occur during the drawing process, which affects the quality of the yarn.
draw weight difference
The problem of weight difference on the same machine is not only related to the manufacturer’s inadequate guidance, installation, and debugging of draw frame equipment technology, but also closely related to factors such as improper use of adjustment equipment in the spinning mill. Common reasons are as follows:
a) The bell mouth is too large, the pressure roller is deformed, the pressure roller bearing is damaged, the pressure roller is aged (grooved), the front pressure roller pressure spring is aged, and there is no oil between the pressure roller pressure spindle and the pressure spring.
b) The position of the bundler is downward or backward, causing some fibers in the cotton web to rush straight to the front wall of the inner cavity of the bundler, and then flip backward in the radial direction and rush out along the rear edge; the feeding barrel is randomly placed too far away, It will cause accidental drafting of the sliver. Mark the position of the sliver can on the ground and supervise and educate the operator to operate it correctly.
c) The cotton guide ring is not in a horizontal state or the gap between the two slivers is too small, which causes excessive tension in the fed sliver, causing unexpected drafting of the sliver.
d) The diameter of the single-eye or two-eye rubber rollers is different or exceeds the service limit, which directly causes eye discrepancy; the pressure spring exceeds the specified period, the pressure mandrel is deformed, and other reasons cause unstable pressure.
f) The tilt of the pressure hook at the pressure position will not be repaired or the butterfly spring piece has been damaged; the diameter of the bell mouth is inconsistent from left to right or the aperture is too large or too small.
g) The roller spacing in the drafting distribution does not match the light and heavy teeth, and the tension adjustment is unreasonable; the pressure rod is deformed and misaligned; the pressure rod adjustment ring is inconsistent or deformed; the experimenter’s sampling and weighing inspection operation methods are not standardized, and often Repeated misadjustments can cause drawing eyelash problems.
Defect strips with sandwich fiber bundles
Such defective strips are generally only discovered during production on the roving frame and are highly concealed. Usually, when the roving frame is in normal operation, some spindle positions on individual machines suddenly appear to be unable to stretch and frequently break ends. Only after changing the machine and feeding sliver can the situation return to normal. After checking the faulty sliver, it was found that there were wrinkled fiber bundles at every other section in the sliver. The fiber bundles were neither flannel flowers, flying flowers, or dirty flowers attached, but were completely good fibers.
After inspection, the draw frame corresponding to the production was in normal condition. The spun sliver was evenly dry and had a good structure. The cause of the problem could not be found. After questioning the on-duty lathe, he learned that the side of the front rubber roller was damaged due to insufficient cleaning and inspection. The thick layer of floral fabrics was still being spun, but was not found and cleaned in time. After cleaning, the defective strips that had been spun were not tracked and flowed to the subsequent process.
After repeated tests and analysis, as long as the surface of the front roller and front rubber roller is covered with more floral clothing, the spun cotton sliver will produce sandwich fiber bundle defects. This phenomenon is generally easy to occur when the sugar content of the raw cotton is high or the relative humidity in the workshop is high.
In response to this problem, it is necessary to improve the anti-winding and anti-winding performance of the rubber roller. Keep the lower roller cleaning and wiping device normal on the equipment, and the upper cleaning flannel has a good effect. In production, focus on the operation cleaning cycle, and improve the responsibility of the operator. Once an abnormality is discovered, Timely tracking and processing.
Drawing details
a) When drawing out detailed defects in parallel driving, you must first consider whether the transmission key is loose. Generally, when the key is loose, mechanical waves will be displayed on the spectrum. Secondly, consider whether the tension draft, guide draft and coil draft are too large. If details occur in the rear area when starting, the method to check whether the key of the transmission part is loose is: hold the front roller with one hand and turn the pulley with the other hand. If there is obvious gap, the transmission part should be checked. It may be caused by loose keys, worn gears, etc.
b) According to production experience, when multiple vehicles reproduce car details, or multiple equipment occasionally and intermittently show details, the design of process parameters is in a critical state, which is most likely to cause it. At this time, improper process design should first be considered possibility. However, in actual production, drawing details may also occur due to both mechanical and process reasons, and sufficient attention should be paid to them.
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