The function of the draw frame is to improve the internal structure of the fiber sliver, thereby improving its long-segment uniformity and reducing weight unevenness. Therefore, the care and maintenance of the draw frame is closely related to product quality. Here are some relevant experiences.
Method 1: Regularly check the status of the roller bearings to reduce the generation of mechanical waves
The roughening process is one of the key processes for spinning enterprises to control and stabilize the quality of semi-finished products. The impact of mechanical waves in the process on the subsequent processes and even the quality of the cloth is particularly important. Therefore, equipment inspection and strict control must be strengthened. By analyzing and processing the causes of mechanical waves at 13 cm to 15 cm and 78 cm to 80 cm on the sliver spectrum of the FA317 draw frame, the CV value of the draw frame was significantly improved.
The mechanical wave reflected on the spectrum is the “chimney”, which generally occupies one channel, and when the frequency of the mechanical wave is between two adjacent channels, the two phases Adjacent channels will be touched, so the spectrogram shows that two adjacent channels are occupied; in some cases, due to slight changes in the periodic fluctuations of the channels, the “chimney” may occupy 3 or 4 channels. Mechanical waves have inherent wavelengths and are accompanied by harmonics. Therefore, analysis is most accurate only by grasping the fundamental wave.
In order to prevent the generation of mechanical waves, it is necessary to regularly check the condition of the roller bearings, the wear of the shaft and holes, the looseness of the keys and keyways, the wear and shape of the gear tooth tips, and the bearings. Regularly check the shaking condition, and refuel the bearing parts regularly to ensure that there is no oil shortage or damage; regularly check the tightness of the toothed belt of the transmission roller, clean the dirt embedded in the tooth gap in a timely manner, and after discovering poor gear meshing or wear It must be dealt with promptly.
In specific work, the lubrication status of the rollers should be checked regularly, and the bending rollers should be corrected; oil should be added regularly, the bushings should be cleaned, and the rubber rollers should be calibrated to prevent problems caused by the bushings and rubber. The drafting mechanical wave caused by the poor operation of the roller; strengthen the inspection of the transmission toothed belt, requiring the toothed belt to be free of wear and moderately tight; when changing the type, replace and inspect the rubber roller to ensure its surface roughness and straightness degree; strictly check the drafting channel during shift handover to prevent the bushings and rubber rollers from jumping.
Method 2: Maintain key equipment to play the role of self-levelling
The FP sensor is installed on the FA322B type The bell mouth detection device of the high-speed draw frame is a precision measuring mechanism. When cleaning and dealing with blockage problems, if you are not careful, it will be scratched or damaged, resulting in inaccurate detection signals or failure of the quality monitoring system. Frequent alarms affect driving efficiency. Therefore, special tools should be used for disassembly and cleaning, and it is strictly prohibited to scratch or hit it with hard objects.
It should be ensured that the air source supplied to the FP sensor is oil-free, free of debris, and dry. However, some users did not pay attention to this and used old-fashioned air compressors, resulting in oil contamination in the air source, causing a short circuit in the bridge circuit in the FP sensor, and ultimately rendering it unusable.
The T/G roller device is mainly responsible for detecting the thickness signal of the fed sliver. If it is not cleaned regularly, the cotton will go around the grooves of the concave and convex rollers. Over time, more and more cotton will accumulate. Finally, the signal given by the displacement sensor is biased, which affects the leveling effect of the entire machine.
The purpose of encrypting the operation panel is to prevent random operations by unrelated personnel. Some users do not strictly manage passwords, causing many people to operate at will, which in turn causes abnormalities in the leveling system and produces waste slivers. In addition, it is necessary to develop the good habit of promptly cleaning the waste cotton in the cotton suction box, regularly refueling high-speed rotating mechanical parts, regularly replacing the oil in the gear box, and promptly cleaning the air duct and fan blades of the frequency converter.
With the development of spinning technology towards high speed, large packages and short processes, as well as the continuous improvement of market requirements for yarn and fabric quality, it is equipped with an auto-leveling device. High-speed draw frames are welcomed by more and more cotton textile companies. Practice has proved that the use of the FA322B high-speed belt autoleveling draw frame and the combined process after combing shortens the spinning process, ensures spinning quality, reduces labor costs, and also improves the risk of overripe and rotten yarns. The problem.
Method 3: Pay attention to parameter settings to ensure dynamic closed-loop monitoring
The FA387 machine is a digital For high-speed draw frames, the machine’s drafting, speed, fixed length and other parameters can be set through the human-machine interface. At the same time, the main drafting multiple can be accurately set and dynamically monitored in a closed loop.
Enter the “System Menu” and select “Parameter Settings”. After entering the password, you will automatically enter the basic “Parameter Settings” screen. Set the strip speed, low speed speed, barrel fixed length, low speed length, suction delay and speed ratio values according to the process. The outlet speed is usually 200 m/min ~ 500 m/min, the low speed is 100 m/min ~ 200 m/min, and the fixed length of the can can be set according to the size of the can. The low-speed length is generally 50 m to 200 m. It is appropriate to increase the speed after the yarn is in contact with the upper coiling disc. The suction delay is set to 3 s to 10 s. The speed ratio is set to 0.8~1.2, usually set to 1.0. This is because the speed is adjusted by frequency conversion. When the power frequency fluctuates, the actual output speed is inconsistent with the set speed. The speed ratio can be adjusted to make the speed set value consistent with the actual output. The values are consistent.
In the “Design rear area draft C” item on the touch screen, select “Rear area draft synchronous pulley”, the machine will automatically calculate�Zone draft multiple. At the same time, manually replace the synchronous pulley, and its number of teeth should be consistent with the touch screen settings. The machine is equipped with a total of 13 synchronous pulleys of different specifications, corresponding to the rear draft ratio from 1.1 times to 2.04 times.
After the setting is completed and the weight and dryness of the sliver are tested to meet the requirements, be sure to select “Join” in the “Closed-loop Control” item on the touch screen. In this way, one roller and four The draft ratio between the rollers is under monitoring. When the draft ratio exceeds 0.01 times the design draft ratio, the machine will stop in time to ensure the quality stability of the sliver produced by the machine under abnormal conditions such as unstable voltage. . Finally, select “Close” in the “Large Hood Switch” item to ensure the safety of blocking the car after driving. </p
