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Discussion on the application of detection technology in Modern Spinning Engineering (Part 1)

1 the important role of detection technology in modern spinning engineering

in the process of textile product quality detection, the fabric surface detection basically adopts the full inspection method; For the quality inspection of cotton yarn, because most of the inspections are destructive tests, we can only use random sampling inspection. Compared with weaving engineering, spinning engineering has more production units (i.e. spinning spindles). During random sampling inspection, it is likely that some spindles with quality defects will not be able to collect samples for detection for a long time. 4. Experimental steps: the average quality of cotton yarn represented by the sub sample level can not completely determine the fabric quality, which is often in a batch of cotton yarn with the same overall level, The defective products of individual rolls will affect the quality of the whole cloth surface and practical quality. With the continuous progress of textile technology, especially the rapid development of electronic information technology and computer technology, detection technology has been more and more widely used in spinning engineering. Accelerating the development of testing technology and promoting the application of testing technology are of great significance to strengthen the process quality control of spinning production, improve and perfect the shortcomings of traditional yarn quality testing methods, improve the quality level of textiles, realize the modernization of spinning production and promote the progress of textile technology

detection refers to the method of detecting the characteristics of the tested product directly in the production process, but for shoes, it is non slip. If shoes are scratched in rainy days and snowy days, it will directly affect their own safety problems. In many processes of spinning engineering, detection, automatic adjustment and automatic detection technology have been used earlier. Automatic detection of cotton bale height, automatic detection and control of cotton box storage in the cotton cleaning process; The self leveling system of carding process and the function of detecting neps and impurities; Self leveling system of drawing process; Spinning tension of roving frame 4 In case of major failure of the experimental machine, contact the monitoring system with the manufacturer of the experimental machine; The detection technology has been successfully applied to the automatic detection of end breakage in spinning process and the electronic yarn cleaning function in winding process. In the spinning production process, the drawing process is the last process to control the sliver quality, and the winding is the last process to remove defects and control the yarn quality. The detection technology of drawing frame and winding machine should be widely used and have obvious effect. Taking the typical vouk sh802e, Unimax drawing frame and Savio Orion winder as examples, this paper discusses the application and practical effect of the detection technology of drawing process and winder process

2 application of typical detection technology in key spinning processes

2.1 application of drawing process detection technology

sh802-e and Unimax drawing frame detection technology includes self leveling system, quality detection and control system and mechanical alarm system

2.1.1 drawing frame self leveling system

sh802-e and the USC and USG self leveling systems on Unimax drawing frame work on the principle that a pair of concave convex rollers are used to continuously sample the sliver fed into the drawing frame, detect the change of its feeding amount, convert the displacement of the concave convex roller into a voltage signal, and after computer processing, control the servo motor to change the drafting multiple of the main drafting area of the drafting system, Make the output cotton sliver achieve the purpose of evenness. Compared with the traditional non self leveling drawing frame, the self leveling drawing frame has the following advantages in the quality control of drawing output:

(1) the change of drafting multiple in the drafting area is synchronized with the reduction of feeding volume noise in time

the traditional weight control method of drawing spinning is to take samples at regular intervals during the production process of the drawing frame, and compare the detected weight with the design weight, When the weight of off-line detection exceeds a certain range of the design weight, manually adjust the drafting gear and change the drafting multiple to make the spinning weight consistent with (or similar to) the design weight. The cotton sliver that is too heavy or too light will be reused as unqualified products. When the feeding sliver changes systematically due to previous reasons (such as cotton blending changes, falling process changes, etc.), this method can adjust the weight of the output sliver to make the yarn count consistent. But in the process of regulation, there is obvious hysteresis. When the feeding sliver changes irregularly due to accidental factors (such as holes in the cotton roll, cotton bleeding, white absorption, lack of sliver, etc.), it is difficult to find its change by regular sampling. Even if this change is found accidentally, it may be generalized, and the drafting multiple of the drawing frame can be easily adjusted, resulting in more serious system unevenness. USC and USG open-loop self leveling systems adjust the change delay of drafting multiple by setting the dead zone length, so that the drafting change is synchronized with the change of feeding amount, effectively avoiding the adjustment lag in the traditional adjustment method and the negative control of irregular changes

(2) the change of drafting multiple in the drafting area is synchronized with the change of feeding amount

in the traditional drawing spinning weight control method, it is usually stipulated that when the output strip deviates from the standard weight by more than ± 1%, one crown tooth of the drawing machine is adjusted, and when the deviation from the standard weight is more than ± 2%, it is treated as cotton sliver return. Even if this artificial regulation is reasonable, if the interference factors in the drafting process of roving and spinning are excluded, when the difference of cooked sliver weight is ± 1%, the difference of yarn weight will also be ± 1%. In the drawing frame drafting mechanism, adjusting a crown tooth can only change about 1% of the drafting multiple. If minor adjustment is required, either increase the number of crown teeth or increase the number of drafting pairs, which is difficult in mechanical design. When comparing the measured weight with the standard weight in the off-line detection, the standard weight is the dry weight or the wet weight under a certain moisture regain rate, while the measured weight is the wet weight under the actual moisture regain rate of the production environment. The actual moisture regain is unknown in the weight detection, and the actual moisture regain can be calculated only after a long time of drying. Therefore, when adjusting the drawing weight according to the measured weight, It is always the default that the moisture regain at the time of detection is consistent with that at the time of last detection, so it is not rigorous. In the self leveling drawing frame, when there is a difference △ g between the actual feeding amount g and the theoretical feeding amount go, the actual total drafting multiple Q1 and the theoretical drafting multiple Qo comply with the following leveling equation

q1=qo* (1+ △ g/go)

this formula theoretically shows that as long as there is a difference △ g between the actual feeding amount g and the theoretical feeding amount go on the drawing frame, there will always be an actual drafting multiple Q1 corresponding to it, and the change law is a continuous straight line. In practical application, by adjusting the magnification of the autoleveller, the response of the drafting multiple to the change of the feeding amount is corrected, so that the relative change of the drafting multiple is consistent with the relative change of the feeding amount. In addition, the detection mechanism of USC and USG self leveling instruments is a combination of machinery and electrical appliances, which effectively eliminates the influence of moisture regain in traditional weight adjustment methods


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