Quality control of combed slivers
(1) Quality indicators of combed sliver
Combed cotton yarn is used to spin high-end products, so the quality requirements for combed sliver are extremely high. Due to the different spinning varieties, raw cotton conditions and production conditions of each factory, the control range of the quality index of combed sliver is also different. The general control range is shown in Table 5-2.
Combed cotton sliver quality indicators
(2) Reduce nep impurities and combed yarn defects
Combed cotton yarn has higher quality requirements, and the number of neps and impurities is higher than that of the same yarn. The linear density of carded cotton yarn is less than half, because the combing machine can remove a considerable amount of neps and impurities, especially the impurity removal rate reaches 50% to 60%, and the neps can remove 10% to 20%.
To reduce nep impurities and yarn defects, in addition to rationally selecting raw cotton, giving full play to the impurity removal function of the cleaning and carding processes and preventing the occurrence of neps, the following points should be paid attention to during the combing process:
( 1) Improve the roll preparation process, improve the quality of the rolls, and strive to improve the longitudinal and transverse uniformity of the rolls and the straightening and parallelism of the fibers to give full play to the carding effect of the combing machine.
(2) Improve the mechanical condition of the carding machine, especially the condition of the carding needles, which is the key to improving the carding effect. For example, the needle specifications and needle planting density of the cylinder and top comb should be reasonably adjusted to prevent needles from being broken or missing, keeping the comb needles in good working condition, trimming the brushes in a timely manner, improving the flatness of the brushes, and maintaining the elasticity of the bristles, so as to improve The working efficiency of the brush ensures that it can clean the cylinder needle surface, etc.
(3) Correctly grasp the combing process, and reasonably adjust the timing of the forward rotation of the separate rollers, the positioning of the cylinder bow plate, the closing timing of the nip plates, and the combing distance.
(4) Reasonably grasp and control the combing noil rate. According to the quality requirements of the cotton yarn being spun, the noil rate should be reasonably determined, and the status of noil should be paid attention to at all times to reduce the table difference and eye difference of noil.
(5) Strengthen operational governance. During operation, attention should be paid to the sticking of small rolls to prevent unclear layers or damage to the combing needle when feeding thick layers, which will affect the quality of the cotton web. At the same time, the cleaning cycle of various parts of the combing machine should be correctly formulated and implemented, and better pile board structures and materials should be adopted to reduce combing yarn defects.
(3) Reduce the unevenness of combed sliver
Since the cycles of the cotton web output from the combing machine are combined separately, the combed sliver has larger periodic segment unevenness. After the combining effect of the subsequent process, the periodic unevenness of the combed sliver can be greatly reduced, and because the fiber separation and straightening parallelism in the combed sliver are better, there are fewer short lint and defects, which is beneficial to Due to the drafting process in the subsequent process, the combed sliver has better evenness.
There are many factors that affect the evenness of combed sliver. On the basis of improving the quality of small rolls and maintaining normal organizational status, the following points should also be paid attention to:
(1) Reasonably adjust process parameters and correctly determine the timing. Positioning;
(2) Correctly control the tension draft of each part to reduce accidental elongation;
(3) Keep the passage through which the cotton web and sliver pass through clean;
(4) Strictly control the workshop temperature Humidity, so that the temperature and humidity of the workshop are controlled within the specified range, that is, the temperature is 20 to 30 degrees Celsius, and the relative humidity is 55% to 60%, so as to avoid improper control of temperature and humidity, which may cause the winding roller, winding roller, cotton web to break and coil. Problems such as blocked inclined pipes.
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