Hidden crossbar causes and preventive and corrective measures
Hidden crossbar refers to the phenomenon that the coil size changes periodically during a cycle of machine operation and appears unevenly on the cloth surface. Generally speaking, the raw materials cause hidden crossbar is less likely, mostly for mechanical wear and tear after adjustment is not timely produced by the periodic tension is not uniform, thus resulting in hidden crossbar.
1.1 Causes
a. Due to the installation accuracy is not high, or due to the aging of the equipment produced serious wear, circular knitting machine cylinder level and concentricity deviation from the allowable tolerance. Common problems occur in the transmission of large gear disk positioning pin and machine frame positioning groove between the clearance is too large, resulting in the cylinder in the operation is not smooth enough, seriously affecting the yarn into the loop as well as out.
In addition, due to equipment aging, mechanical wear and tear, prompting the main drive gear disk longitudinal and radial shaking increase the concentricity of the cylinder to produce deviations, resulting in fluctuations in the tension of the feeding yarn, resulting in abnormal coil size, the seriousness of the cloth will appear in the hidden horizontal stripes.
b. In the production process, the yarn feeding mechanism of the variable speed disk adjusting slider embedded in foreign objects such as flying flowers, so that its roundness is affected, the speed of the synchronous toothed belt abnormal, unstable amount of yarn feeding leads to the generation of hidden cross-stripes.
c. The round machine adopts negative yarn feeding mechanism, it is difficult to overcome the shortcomings of large differences in yarn tension in the process of yarn feeding, which may easily lead to accidental elongation of yarn and differences in the amount of yarn feeding, thus forming the hidden horizontal strip.
d. The circular knitting machine with intermittent winding mechanism has large fluctuation of tension in the process of winding, and the length of the coil is easy to produce differences.
1.2 Preventive and corrective measures
a. The gear disk positioning surface plating is appropriately thickened to control the gear disk wobble between 1~2 silk. On the bottom of the ball track polishing, grinding, plus grease to the bottom of the barrel with a soft thin elastomer pad flat, strict control of the barrel radial shaking in the 2 silk. The triangle of the sinker needs to be corrected regularly, so that the distance between the triangle of the sinker and the tail of the new sinker is controlled between 30 to 50 threads, and the positional deviation of the triangle of the sinker is controlled within 5 threads as far as possible, so that the sinker can keep the same yarn tension when retreating from the loop.
b. Control workshop temperature and humidity. General temperature control at about 25 ℃, relative humidity control at 75%, in order to prevent the phenomenon of adsorption of dust due to static electricity, while taking the necessary measures to maintain cleanliness and hygiene, strengthen the maintenance of the machine to ensure that all rotating parts operate normally.
c. Negative mechanism to transform into a positive storage order to give the mechanism, reduce the tension difference in the process of guiding the yarn, it is best to install the speed monitoring device to stabilize the feeding tension.
d. Transform the intermittent winding mechanism into a continuous winding mechanism to ensure the continuity of the cloth curling process and the stability and uniformity of the winding tension.
Monofilament cross-bar causes and preventive and corrective measures
Monofilament cross-stripe refers to the surface of the fabric, one or several cross-linking coils than the other cross-linking coils are too large or too small, unevenly spaced phenomenon. In the actual production of monofilament cross-stripes caused by raw materials is the most common.
2.1 Causes
a. Poor yarn quality, monofilament color difference phenomenon such as tightly twisted silk, not the Division of the batch number of chemical fiber filament, not color-covered filament or yarn mixing of different yarn counts, which directly leads to monofilament cross-bar production.
b. Yarn cylinder size difference or the silk cake itself forming the existence of convex shoulders and collapsed edges, resulting in uneven yarn winding tension, easy to produce monofilament cross-stripe. This is because the different size of the yarn cylinder will make its winding point and the diameter of the annealing air circle is different, the law of change of annealing tension is bound to have a big difference. In the knitting process, when the tension difference reaches its maximum value, it is easy to cause the different amount of yarn feeding, thus leading to uneven coil size.
c. The use of porous and ultra-fine denier raw materials processing, the silk channel should be as smooth as possible, a guide hook slightly rough or grease curing, it is very easy to cause the raw material more than one monofilament fracture, monofilament color difference is also produced. Compared with conventional raw material processing, the requirements of the equipment are more demanding, and the cloth is also more likely to produce monofilament cross-stripe.
d. Machine adjustment is not in place, somewhere in the pressure needle triangle is too deep or too shallow, so that the yarn tension abnormality, the formation of the size of the coil production differences.
2.2 Preventive and corrective measures
a. Ensure the quality of raw materials, as far as possible, use brand-name manufacturers of raw materials, raw materials, dyeing, and physical indicators of the change in the requirements of strict requirements, dyeing requirements standard at 4.0 or more, physical indicators of the coefficient of variation should be small.
b. Selection of the best fixed-weight silk cake processing, fixed-weight silk cake selection of rolled diameter of the silk cake on the machine to use, found that the appearance of poor molding, such as the existence of convex shoulders and collapse of the edge of the silk cake, must be removed from the use. When dyeing and finishing, it is best to dye small samples, such as the emergence of horizontal stripes, then choose to change the dyeing of non-sensitive colors or add cross-stripe treatment agent to eliminate or reduce the cross-stripe.
c. The use of porous and ultra-fine denier raw materials processing, must be the first raw material appearance of hair strict control. In addition, it is best to clean the silk road, check whether each guide structure is smooth. In the production process to observe the weft storage whether there are tangled hair, such as found, should immediately stop to find the cause.
d. Ensure that the depth of the pressure meter triangle of each way of feeding yarn is consistent, use the yarn length gauge to fine-tune the position of the bending yarn of each triangle, and keep the amount of feeding yarn consistent. In addition, check each road bending triangle has no wear, bending triangle adjustment directly affects the size of the yarn tension, yarn tension directly affects the formation of the coil people small.
Conclusion
1. round machine fabric production due to the quality of raw materials caused by the most common monofilament crossbar, the choice of good appearance, good quality raw materials for round machine production is very necessary.
2. The routine maintenance of machinery is very important, long-term operation of some machine parts wear, so that the circular knitting machine cylinder level and concentricity deviation increases, very easy to cause the production of horizontal stripes.
3. In the production process, the pressure needle triangle and the adjustment of the sinker arc is not in place, so that the coil abnormality, resulting in an increase in the difference between the feeding tension, resulting in the feeding of yarn volume is not the same, resulting in the production of horizontal stripes.
4. Circular fabrics due to the characteristics of its coil structure, the sensitivity of different organizations of the fabrics appear cross-stripe is also different, usually speaking, single-area fabrics, such as sweatshirt cross-stripe probability is relatively large, on the machinery and raw materials, the requirements are relatively high. In addition, the use of porous and ultra-fine denier raw material processing fabrics have a higher probability of cross-stripe.