1. Roving twist coefficient
When the twist coefficient of the roving is large, the tightness of the roving strips increases, the cohesion force is good, the friction resistance between fibers increases, and the draft force response increases. When the spacing distance of the back zone of the spun yarn and the draft multiple of the back zone remain unchanged, Under such conditions, the strands cannot be effectively untwisted and enter the main drafting area with a larger twist, resulting in the phenomenon of unable to be drafted. However, the twist coefficient of the roving should not be too small. If it is too small, accidental drafting may occur when feeding the spinning machine, resulting in details and affecting product quality.
2. Spinning yarn guide motion
When the moving direction of the spun yarn guide stroke is the same as the twist direction of the sliver, the drafting force is large and the holding force is less than the drafting force and draft occurs. When the twist direction of the strands is opposite to the movement direction of the yarn guide, the drafting force is small, which is beneficial to reducing the drafting problem.
3. Roving weight
The increase in the roving basis weight means that the drafting force of the spun yarn increases. In the same rubber roller state and after When the zone draft multiple and roving twist coefficient are certain, the holding force of the spun yarn required by the heavy roving is greater than the holding force required by the light roving, so the roving weight has a higher holding force for the spinning draft. requirements. The ration of the roving should be adapted to the nip spacing to avoid drastic fluctuations in the drafting force of the yarn at the nip during the spinning process, which would affect the normal drafting of the spun yarn.
4. Spinning roller gauge
Small roller spacing is conducive to the control of floating fibers in the sliver, which increases the drafting force of the sliver during the drafting process and tends to prevent the sliver from being drafted. After the roller gauge is increased, the ability to control the floating fibers in the whiskers is weakened, so that the fibers can be well controlled and drafted normally, avoiding the phenomenon of unable to be drafted.
5. Drafting in the rear area of spun yarn
After the drafting multiple of the rear area of the spun yarn is increased, the number of fibers in the cross section of the sliver entering the main drafting area is reduced, and the drafting force is reduced, which is beneficial to the drafting jaws on the fibers in the sliver. The control can reduce the phenomenon of draft failure, but in general, it is not conducive to the improvement of yarn quality. Most current production enterprises use larger center distance of the back roller of spinning yarn and smaller draft ratio of the back area. Roving twist coefficient
6. Spacing between spun yarn jaws
The smaller jaw spacing block is conducive to strengthening the control ability of the apron jaws on the drafted yarn, and has better control over the edge fibers of the yarn when the fiber speed is changed, thereby improving the results. The yarn sliver is dry. After the distance block is increased, the control force of the apron clamp on the sliver is weakened, which can reduce the phenomenon of draft failure, but it will have a certain impact on the quality of the yarn.
7. Spun yarn roller pressurization
The roller pressure is small, and the drafting jaws have weak control over the fibers, resulting in the fibers in the sliver not being well controlled and resulting in the phenomenon of inability to be drafted. After the roller pressure increases, the friction force of the drafting nip increases, so that the fibers in the sliver can be well controlled and drafted normally. The pressure of the front, middle and rear gears of the cradle should be distributed reasonably to avoid drafting failure in the rear area and resulting in failure to open.
8. Spinning yarn top roller
For new rubber rollers with a paint layer on the surface, the surface paint is thicker, and the gripping force of the rubber roller surface is greatly weakened. During the drafting process of the rubber roller, the slippage rate is high, so that the yarn cannot be effectively stretched. The coating layer on the surface of the old rubber roller is thin, the friction factor on the surface of the rubber roller is large, and the holding force of the rubber roller on the yarn sliver is greater than the yarn sliver. Drafting force, the whiskers can be stretched normally. Since the surface of the untreated rubber roller is not chemically treated, the surface of the rubber roller can be in direct contact with the whiskers. The friction coefficient is large, and it has a large holding force and can overcome large drafts. It is an effective measure to solve the problem of poor drafting. In winter, due to the low temperature, the top roller will become hard if not treated, and the slippage rate will increase, making it easy to produce hard ends.
9. Raw material condition
In daily production, the raw materials are in a state of change at any time. The fiber quality length in the cotton sliver is lengthened (such as increasing the combed sliver content) or the length uniformity is good, and the friction coefficient between the fibers in the sliver becomes larger. During the drafting process, the drafting force response increases. When the spinning process remains unchanged, the drafting jaws cannot effectively control the fibers in the sliver, resulting in the sliver not being able to be drafted normally and resulting in draft failure. phenomenon, other processes need to be adjusted.
10. Temperature and humidity
When the humidity in the workshop increases, the friction coefficient between the fibers in the sliver becomes larger, and the friction resistance response increases, which increases the drafting force of the sliver. When the spinning process remains unchanged, the drafting jaw cannot Effectively control the fibers in the sliver to avoid drafting failure. The workshop should reasonably control the temperature and humidity according to seasonal changes, raw material conditions and other factors to ensure normal production and avoid drafting failure.
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