Research On Yarn State Detection In Circular Weft Knitting Process

In the course of weaving,the yarn will inevitably appear broken,entangled,etc.Therefore,it is necessary to monitor the yarn status during the programming of the circular weft machine A circular weft machine contains multiple yarn conveying,each yarn conveying is not continuous.Therefore,when the circular weft machine is in operation,there are different states of the yarn,such as normal delivery,normal non-conveyance,yarn breakage,and yarn winding.Yarn breakage will cause the yarn to be unable to be conveyed;yarn entanglement will cause the yarn to be excessively conveyed and easily cause damage to the knitted components.Therefore,these faults need to be detected in time.As the yarn is being conveyed,there is a significant lateral vibration phenomenon.This article will design a reasonable detection method based on the characteristics of the transverse vibration of the yarn to realize real-time monitoring of the yarn state during the operation of the circular weft machine.First,the production process of the circular weft machine and the yarn conveying method are introduced.The difference in transverse vibration frequency characteristics between normal and abnormally transported yarns in the weaving process is analyzed.Designed the experimental platform,using high-speed camera and motion analysis software,based on the actual production process parameters of the circular weft machine,through experimental research,the frequency domain of the yarn transverse vibration and the yarn initial tension,yarn conveying speed,yarn conveying variable speed This relationship provides a practical basis for yarn condition monitoring.Secondly,according to the frequency domain characteristics of the transverse vibration of the yarn,a detection circuit based on infrared light sensitivity is designed to convert the yarn vibration into a rectangular wave signal of standard amplitude.The correlation between the frequency of the rectangular wave signal and the frequency domain of the transverse vibration of the yarn is analyzed through experiments.It is verified that the detection circuit can effectively measure the transverse vibration state during the yarn conveying process.Finally,using the detection circuit,a circular weft yarn conveying failure monitoring scheme composed of a monitoring main controller and a detection sensor is designed to monitor the circular weft yarn conveying failure in real time.In practical applications,detection sensors are installed on each yarn conveying path.When any of the yarn conveying faults occur,the monitoring main controller will upload the fault information to the circular weft controller at the same time as the fault alarm,to ensure timely shutdown when the fault occurs.The program has been practically applied in enterprises to verify the stability and reliability of yarn condition monitoring.