Key process adjustment methods
1. Roller distance. The roller distance is directly related to the fiber length and ration. The roller holding distance cannot be less than the fiber length, otherwise the fiber may be held by two pairs of rollers at the same time and broken at a certain moment. If it is greater than the fiber length, During the drafting process, it is difficult to control fiber movement, and there are many floating fibers, which affects the evenness of the evenness. Therefore, if the gap is too large or too small, it will be detrimental to the quality of the semi-finished product. Generally, the roller gauge is determined according to the fiber quality length. The quality length is long, the gauge is large, the semi-finished roving is quantitatively heavy, and the roller gauge is slightly enlarged.
2. Roving twist coefficient: The roving tension is low, and the roving twist coefficient is related to product quality and output. The twist coefficient is too small. Accidental drafting is prone to occur, causing end breakage and uneven products. When the twist coefficient is too large, the drafting force will be too large when the spun yarn is stretched, resulting in uneven yarn formation or the appearance of small mice under hard ends. Pure cotton or chemical fiber is determined by many factors. Generally, chemical fibers have long fibers and high strength, and the twist coefficient can be smaller. The selection of twist coefficient is generally based on fiber length, fineness, roving basis weight, and spinning back zone technology. There is a lot of twist. At the same front roller speed, only by speeding up the spindle speed or slowing down the front roller speed at the same spindle speed can we meet the process requirements. Therefore, the twist is large and the output is low.
3. Roving tension and elongation roving tension change with factors such as roving basis weight, twist size, raw cotton quality, temperature, humidity, and mechanical state. Therefore, adjusting the roving tension is also complicated and requires accumulating experience in practice. Once the yarn is doffed, the tension of the small yarn usually elongates abnormally. Adjust the starting position of the cannon belt; the small yarn is normal, and the tension of the medium yarn and large yarn is too large or too small. Adjust the tension ratchet or coaxial gear; the tension of small yarn and large yarn is appropriate, and the tension of medium yarn is too tight or too loose, adjust the tension compensation gear. The roving tension is inappropriate and the elongation is large. It will be too tight or too loose during winding, which will affect the winding length or evenness, increase roving breakage and yarn defects, affect the output quality, and cause breakage and yarn breakage when the fine yarn unwinds. Defects bring disaster. The elongation of roving is generally controlled between 1.5% and 2.5%, and the difference in elongation of large and small yarns is controlled within 1.5%. The weight unevenness (long segment 5 m) is about 1.5%.
4. The influence of temperature and humidity on product quality. Physical properties such as fiber strength, fineness, elongation, and elasticity are closely related to the relative humidity in the workshop. When the temperature is lower than 18°C, the relative humidity is too small and the surface of the cotton fiber becomes waxy. , the plasticity is reduced, the fiber is fragile, the strength is reduced, static electricity occurs, and it is easy to wind around rollers and rubber rollers, causing deterioration of the evenness; when the temperature is 24℃~26℃, the relative humidity is suitable, the cotton wax is soft and hard, and the raw cotton is easy to decompose or single fiber It is beneficial to opening, dust removal and drafting; when the temperature is too high and the relative humidity is too high, the cotton wax softens and the friction between fibers increases, which affects normal drafting and causes uneven evenness. Therefore, the relative temperature in the roughening workshop is too high, which makes it easy to wind the rollers, rubber rollers, and the hollow arms of the spindle flyers. The resistance is large, there are many ends breakage, and the yarn is too tight, which affects normal drafting, hard ends occur, the relative humidity is too low, and static electricity The effect is enhanced, resulting in more fly flakes, loose roving, poor roving shaping, many broken ends, and poor fiber cohesion, which affects the unevenness and strength of the evenness, increases the labor intensity of the machine operator, and affects the output. The temperature and humidity control requirements for roving are as follows: winter: temperature is 22℃~24℃, relative humidity is 60℃~65℃; summer: temperature is 30℃~32℃, relative humidity is 55℃~65℃.
Causes of uneven roving evenness
There are many reasons for uneven roving. If the pressure is too light, the rubber roller will not be pressed firmly. The distance between rubber rollers and rollers is unreasonable; the bending eccentricity of rubber rollers and rollers exceeds the normal range or the surface is damaged. The rubber rollers and roller bearings are short of oil and damaged; the draft transmission gear is in poor condition, the gear is eccentrically damaged, the meshing is poor, worn out, the pin keys are loose, the drafting parts are defective, the bell mouth is skewed and damaged, the upper pin is deformed, and the jaws are abnormal; The upper pin hits the rubber roller, the rubber ring is broken, the rotation is not flexible, the lower pin rod is bent, and the opening of the cotton collector is incorrect, too large, too small, or damaged. The design of each process parameter is unreasonable, the tension is too large or too small, the drafting configuration is inappropriate, the elongation is too large, the spindle wing is loose, and the spindle shakes seriously, etc.
Solutions to poor roving forming
1. The upper and lower angles are different
Correct the level of the scalloped rod and the balance frame when the spindle flyer palm hole is in the center of the bobbin. Adjust the length of the top wire of the upper cradle to be consistent, and adjust the tension teeth to the same angle each time to make the iron cannon belt move equidistantly.
2. The roving appears.
When correcting the reversal of the lower beam, the reciprocating wheels (hehe teeth and square box gears) reciprocate flexibly without skipping, and the forming mechanism is inflexible (three actions of forming reversal: shifting of the iron cannon belt, changing the lifting speed of the lower beam (Slow down) and change the winding speed; push the reciprocating rotation to change the movement direction of the bottom rib; shorten the lifting stroke of the bottom rib to make both ends of the roving tube conical). It has three functions: deceleration, reversal, and shortening the stroke. , must occur at the same time when the roving is wound to one end of the bobbin, and is completed instantly. Therefore, the function of the forming mechanism is to use the lifting and lowering of the lower beam as a trigger to complete the three actions of deceleration, reversal, and shortening of the stroke.
Molding device�Relevant screws are loose, gear meshing is poor, related machine parts are damaged, tension spring tension is improperly adjusted, device debugging is poor, and the lifting of the lower rail is severely frustrated (the rail is uneven, gears and racks are poorly meshed, pins and screws are loose), and individual problems occur. The spindle wing is loose and the weight of the fed sliver is too light.
3. Off the shoulder
Due to the tension, improper adjustment of the cannon belt, cannon jumping (poor dynamic balance of the cannon, improper installation), poor temperature and humidity, relative humidity, etc.
4. Hard yarn, rotten yarn
The rear rubber roller is lifted up, and the drafting effect in the rear area is poor. The rubber roller is moving, the pressure is abnormal, the tension is too tight, the cotton sliver is unevenly fed, the press palm and the hollow arm of the spindle flyer are hung, the number of yarn winding passes on the press palm does not meet the requirements, and the gear screws related to the forming are loose, causing the long rack to move. Inflexible or too small, the long rack moves equidistantly each time, the relative humidity is too large or too small, and the process configuration is improper.
5. Waist hoop
The forming device functions poorly and the square box reciprocating gear 100T is poorly meshed. The gap between the dovetail pin and the dove head of the center cradle is too large. The cannon belt is too loose, the cannon bearing is damaged, the gear is loose, etc., causing the lower cannon to not rotate, the lifting gear, and the lifting intermediate wheel to mesh poorly, and the screw pin is loose. The tension spring of the forming device is not adjusted too loosely, etc.
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