Process control of the roving frame
The roving machine process parameters mainly include: quantitative, spindle speed, draft multiple, roller grip distance and aprons jaw distance, roller pressure, twist coefficient, winding density, collector and bell mouth diameter, palm roll Number of detours.
1
The ration of upset roving is determined according to the drafting capacity of the spinning frame, the spinning number, and the product quality, among which the spinning number is mainly based. The heavier the roving and the thicker the spun yarn, but if it is too heavy, the spun yarn increases with the draft multiple, which has an effect on the yarn sliver dryness. At present, there is an increase in the basis weight to 10 g / (10 m). The spun yarn is changed to a "V" draft, and the finished yarn is also good. It is worth promoting.
In short, the total draft multiple of the roving frame is determined by the number of spinning frames and the sliver quantity, as well as the draft type of the roving frame. As the current spinning frame develops to a high draft, the roving can be configured with a lower draft Stretching multiple is good for quality. When double-aperture roving is used, the draft ratio can be slightly higher than the three-up, four-down curve drawing, generally 5 to 12 times.
2
The drafting allocation of the roving frame is determined by the drafting type and the total drafting multiple. When the drafting capacity in the main drafting area is large, the drafting ratio in the main drafting area should be large. The drafting area has a larger capacity. Practice has proved that under the condition that the sliver quantity and the roving quantity are unchanged, the greater the post-drawing multiple, the worse the roving sliver dryness. Therefore, the process conditions in the main drafting area When better, the post-draft multiple should be kept small.
3
Post-drawing multiple: Post-drawing multiple has a great influence on the roving sliver. Under normal circumstances, the double-aperture drafting device, due to the strong friction of the aprons, and an elastic jaw, can stabilize the drafting force and make the fiber shift point forward, both concentrated and stable. Therefore, the general post-draft multiple is arranged between 1.08 and 1.4 times. In production practice, we use 1.1 times of rear draft and roving evenness on the A454, FA468E, FA458A, and FA421 roving frames. Of course, the dry quality is also related to the pressure of the aprons. When determining the post-draft multiple, you should first understand the slip ratio of the lower rubber ring to the center roller, and try to reduce the slip ratio of the upper and lower rubber rings as much as possible.
In addition, when the roving is overweight, in order to prevent the delamination of the sliver, a large post-drawing multiple may be adopted. When spinning knitting yarns, in order to prevent the details of the long section of the fine yarn, a smaller total draft multiple is selected Under the circumstances, the draft of the rear area should also be mastered. For the three-up, four-down drafting type, due to the existence of an anti-enclosing arc on the third roller in the rear zone, when the weight of the cooked bar is relatively light, the draft ratio in the rear zone should also be controlled too small, generally 1.17 to 1.36 times.
4
When using a large package and high roving frame, the spindle speed can reach 1000 r / min ～ 1500 r / min, and the roving ration should not be too light, otherwise it will increase the accidental drafting and increase the coarse and fine yarn ends, making life difficult.
5
Twist coefficient: When the fiber is long, well-groomed, and fine, the twist number should be small, otherwise it should be large, and the roving has twist, so that it can withstand the tension in winding and unwinding, and it is beneficial to the drafting of the back region of the fine yarn Fiber control. However, if the twist factor is too large, not only the strength of the roving will be uneven, but also the spun yarn will cause rubber rollers to slip, hard ends, and increased end breaks; otherwise, it is too small, which is prone to accidental drafting, and also increases end breaks, making the product uneven.
6
Roller separation and compression: Roller separation should be determined according to the fiber length, too small damage to the fiber, even hard head, irregular movement of too large fiber, deterioration of CV value and other quality indicators, roller compression is to ensure the roller clamp The mouth has sufficient holding power to prevent the yarn from slipping under the roller jaws and excessive delamination. During the drawing process, can the roller jaws effectively control the fiber, which directly affects the evenness of the sliver, the weight unevenness and the occurrence of roving defects. On the roving machine pressurized by the spring cradle, the spring swings the pin and The stepped lower pin aprons are controlled by jaws, and the original distance of the jaws is determined by the quantitative change of the roving. When the fixed weight is more than 5 g / (10 m), the original distances of 4.5 mm, 5 mm, 5.5 mm, and 6 mm are selected. When the selection is made, it should be equipped with a small jaw under sufficient spring pressure. The product is uniform and favorable, but the spring pressure should be corrected regularly. If the pressure is not consistent, it will cause a large difference between the ingots. If the jaw is too small, it will easily spit out hard heads.
7
The front and middle areas of the roving frame are also equivalent to the role of an additional friction force. The caliber is: the front area should be compatible with the roving basis weight, and the middle area should be compatible with the sliver basis weight.
8
The spindle has no vertical swing head and is controlled within 0.03 mm. The bending is too large, resulting in increased end breaks and irregular thickness.
9
The ingot wing must be dynamic, statically balanced, not skewed, smooth, and the palm pressed tightly. If the yarn is too tight, hairiness will occur, and if it is too loose, it will easily fall off. When the open gear is large, they will collide with each other. If the open gear is small, the yarn will be worn. If the palm press arc is unqualified, the roving is wound tightly and unevenly, and even the defective product is broken, and the end break is increased. In order to keep the machine running normally and reduce wear and tear, it is necessary to correct the wiping regularly.
In short, the correct use of the roving frame is a key link in textile engineering. Only by understanding the connotations can we make better use of the roving frame and produce high-end products.
