In the summer of high temperature and high humidity, it is very difficult to produce combed extra-fine yarn using high-sugar cotton. The author’s company has taken some measures in the production of CJ 5.8 tex yarn to stabilize and improve the quality of the yarn. Here is an introduction as follows.
Material performance
The cotton is made of 70% 237 long-staple cotton and 30% 333 medium-staple cotton. See Table 1 for performance.
Spinning process
A002C cotton picking machine→ A006B type cotton blender→A034 type six-cylinder cotton opener→A036B type porcupine type cotton opener (two sets)→A092A type double cotton box cotton feeder→A076C type single hand winding machine→A186F type carding machine→A272F Type pre-doubling machine → A191B type strip winding machine → A201C type combing machine → A272F type draw frame (two passes) → A454G type roving frame → BS516 type spinning frame → 1332MD type winding machine.
Technical measures
01 Raw material processing
The impact of sugar on spinning production It is very disadvantageous. In order to eliminate the entanglement problem and improve the spinnability of the fiber, BG-1202 high-efficiency anti-sticking agent is selected. The anti-sticking agent is evenly applied on the surface of the cotton bale and left for 24 hours before use. After repeated tests, it was found that 1% anti-sticking agent was more effective and there were no entanglement problems in each process. Before blowing and picking cotton, take samples to test the moisture regain of raw cotton. The moisture regain rate should be controlled below 8.5%. If the moisture regain is high, the workshop temperature can be appropriately increased and the relative humidity can be reduced.
02 Equipment Management
Equipment maintenance should focus on the maintenance and cleaning of key parts, shorten the wiping cycle, and clean the cotton every time. Wipe each part of the dust rod with gasoline once a week. It is required that all debris areas are not stuck and can be collected normally. The roll rollers are wiped every shift; in the carding process, the large and small leak bottoms, coiling discs, and large and small pressure rollers are regularly wiped every week. Clean the dust on the doffer cover and wall board to prevent dust on the channel, and have a dedicated person responsible for cleaning the cover every day to reduce the congestion of the cover and improve the efficiency of debris removal and carding; wipe the combing and drawing processes with gasoline regularly every day Stretching channels, rubber rollers, and coiling discs prevent long-term accumulation of sugar on the machine; reasonable selection of rubber rollers and aprons for the roving and spinning processes ensures that the rollers are smooth and burr-free, and the operator dynamically cleans the roller winding and accumulation.
03 Temperature and humidity control
Due to Raw cotton contains high sugar content and is very sensitive to changes in temperature and humidity. Air conditioners should use low temperature and low humidity. When there is a conflict between temperature and humidity, measures are taken to ensure stable relative humidity. From the cotton bale storage environment to the entire spinning process, a lower relative humidity is used to reduce the moisture absorption and release of raw cotton and semi-finished products. Temperature and humidity fluctuations in production mostly occur before and after the change of operation, and winding problems often begin during this period. Therefore, stabilizing the temperature and humidity in the workshop before and after the handover is the key to preventing the occurrence of winding problems.
Main process design parameters
01 Open-cleaning cotton
Aiming at raw cotton that is long, thin and contains impurities It has many characteristics and adopts the process principle of “grabbing cotton finely, loosening more and beating less, falling early and breaking less”. The operating efficiency of the cotton picking machine is controlled at about 85%, so as to achieve “grasping frequently and catching less” to improve the efficiency of opening and impurity removal. In order to reduce fiber damage, the speed of each department’s beater is appropriately reduced. The speed of the porcupine beater is 520 r/min. Since the raw cotton contains a lot of impurities, two sets of porcupines are opened and the counting is increased to improve the efficiency of impurity removal. At the same time, the temperature and humidity of the cleaning process should be well controlled, with the temperature at 25 ℃ ~ 30 ℃ and the relative humidity at 55% ~ 60%. The moisture regain of the cotton lap should be controlled below 8% to prevent tangling of the combing rubber roller and roller.
02 Carding
Using “light weight, low speed, The process principle of “tight gauge and strong carding” is conducive to improving fiber straightness and reducing card sliver knots. The cotton feeding board is raised by 4 mm and the length of the carding process is increased to reduce fiber damage and reduce the increase rate of short lint. The cylinder and licker-in adopt a large speed ratio of 2:1, which is conducive to the smooth stripping of fibers from the surface of the lickerin by the cylinder, reducing flower return, and reducing neps and short lint of the card sliver. In order to prevent the cotton net from falling when the relative humidity in the workshop is high, the front tension draft ratio is appropriately increased from the original 1.371 times to 1.443 times. Main carding process parameters: card sliver basis weight is 17.331 g/(5 m), cylinder speed is 360 r/min, licker-in speed is 928 r/min, doffer speed is 17 r/min, cylinder licker-in speed Ratio 2.0, cylinder-cover spacing are 0.20 mm, 0.18 mm, 0.18 mm, 0.18 mm, 0.20 mm respectively.
03 Combing
Adopting the process principle of “light weight, small draft”, the combing noil rate is controlled within 13%±1%. In order to reduce the impurities in combed sliver, the quantity of combed sliver should be controlled lightly. The combing cylinder uses a certain serrated integral cylinder, which has strong puncture performance, stable combing quality, high impurity removal rate, and no intarsia. It has a better effect when used in conjunction with the integral top comb. Due to limitations of air-conditioning equipment, the temperature and humidity of the company’s combing process fluctuate greatly, and because the sugar content of raw cotton is high, in order to improve spinability and reduce the problem of winding cots, the combing machine selected Shore A65-degree separating cots. , wipe the surface of the finely ground rubber roller, and micro-treat it with WTB colorless paint. When using it on the car, use a special cleaner to clean the surface oil and dust, then rub a little talcum powder on it, and there will be no glue wrapping after getting on the car. Roller problem. In the spinning process, if the control of the previous process is not good and the combing around the rubber roller occurs, the speed can be reduced and the number of combing nip can be reduced to alleviate the problem.
04 Drawing
Adopting the process principle of “light weight, low speed, large distance”, the first pass is 6 pieces MergeThe back area drafting makes the fibers fully straight and parallel, and the last 6 fibers are combined with the small back area drafting to ensure stable drafting and prevent accidental drafting from damaging the fibers or deteriorating the evenness. Appropriately reduce the diameter of the trumpet head to increase the cohesion between fibers, which will help the cooked strips to be tight and not loose, and avoid adhesion of the strips. A rubber roller with a Shore hardness of A75 is selected for drawing. In order to enhance the anti-winding performance, corresponding micro-treatment measures are taken on the surface. The ground rubber roller is lightly treated with WTB composite coating, and the surface of the rubber roller is coated with paint. It must be completely penetrated and there should be no traces on the surface of the rubber roller. The rubber roller has moderate hardness and good elasticity. After micro-processing, it has strong anti-winding ability, is less affected by temperature and humidity changes, and has the characteristics of wear resistance and aging resistance. It has a significant effect on stabilizing and improving product quality. After testing, it is finally Drawing dry CV is about 2.6%. The main process parameters of drawing are shown in Table 2.
05 Roving
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Adopt the process principle of “light basis weight, low speed, large twist coefficient, small back draft area, small jaw distance, heavy pressure” to give full play to the role of the main drafting area , which is beneficial to control floating fibers, reduce the drafting burden of spinning yarn, and improve the evenness of the yarn. Appropriately reduce the roving speed, reasonably match the front and rear supply, minimize the parking time, and avoid causing entanglement during driving. Since the roving has a light basis weight and small fiber cohesion force, in order to reduce the accidental drafting of the roving on the spinning frame, the fixed length of the roving should not be too large. The roving adopts TC-975 surface untreated rubber roller. The Shore hardness is A75 degrees ± 3 degrees. It is a medium-soft rubber roller with excellent anti-winding performance. It can be used in environments with fluctuating temperature and humidity without emptying the car. Issued normally. The main process parameters of the roving are: the basis weight is 2.252 g/(10 m), the back drafting multiple is 1.211, the twist coefficient is 106, the roller spacing is 25/36 mm, the front roller speed is 116 r/min, and the spindle speed is 700 r/min, jaw spacing is 3.5 mm.
06 Spinning yarn
Adopts “light basis weight, low speed, small back draft area, small jaw gap” The process principle is to strengthen the control of fibers and help improve the evenness of the yarn. The spun yarn uses an aluminum bushing with a Shore hardness of A65 and a treatment-free rubber roller. The rubber roller has a large contact arc surface with the roller and has strong fiber control. Its impact elasticity is 40%, has good elastic recovery, long service life and slow hardness decay. The spinning performance is stable, which is beneficial to improving yarn quality and reducing rough details. Without increasing yarn breakage, appropriately weight the traveler to reduce hairiness. The dry basis weight of the spinning yarn is 0.535 g/(100 m), the total draft ratio is 42.09, the draft ratio in the rear area is 1.2, the twist coefficient is 340, the front roller speed is 125 r/min, and the spindle speed is 13 997 r/min. The jaw gap is 2.5 mm.
07 Winding
The winding process adopts “low speed, The “light tension” process configuration is used to reduce the damage to the strength and evenness of the yarn during the winding process. A metal groove barrel with strong conductivity is selected to control the hairiness increase rate, while keeping the winding channel smooth and clean, and wiping it regularly with alcohol. By taking the above methods and measures, in the summer of high temperature and high humidity, combing and other processes prone to tangling did not occur, and the product quality was stable. </p
