Method and device for detecting core exposure rate of covering yarn

Abstract

The invention provides a method and device for detecting the core exposure rate of covering yarn. The method comprises the steps of transverse unwinding of the yarn, image capture of the yarn to be detected, image processing and data analysis. Transverse unwinding mainly ensures that the core-spun yarn is stable in state during unwinding, and core exposure of the yarn due to untwisting is avoided; the unwound yarn enters an image capturing area through a godet wheel, the area is provided with two cameras and a background plate, the whole capturing process is continuously carried out, images are numbered in sequence, the shot images are imported into a computer through data transmission, and then the computer carries out image processing and data statistical calculation. The method is used for detecting the covering quality of the outer-layer fiber of the ring-spun core-spun yarn on the core yarn, determining the proportion of the exposed area of the core yarn in the whole yarn, and providing a new reference standard for quality evaluation of the core-spun yarn.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of yarn structure performance detection, and particularly relates to a method and device for detecting core yarn core exposure rate. BACKGROUND

[0002] In the textile field, in order to improve the performance of yarn, a method of composite yarn is often used to combine two or more fibers to form a composite yarn. Among them, the core-spun yarn structure is simple and is the most widely used. In various spinning technologies, ring spinning technology is mature, can spin a wide range of yarn fineness, the yarn quality is stable, and the production efficiency is high, so ring spinning is usually used to produce core-spun yarn.

[0003] In order to improve the functionality and practical performance of the yarn, the core-spun yarn is processed, the short fibers are wrapped outside the long fibers or yarns with certain functionality, and a kind of skin-core structure yarn is formed. Compared with ordinary yarn, due to the combination of the properties of core long fibers or yarns and wrapped short fibers, the skin-core structure yarn can combine the advantages of various fiber raw materials to achieve the purpose of improving the functionality of the yarn.

[0004] In the actual spinning process, the nip must also be irregularly swinging due to uneven strip and machine vibration, and the core yarn cannot be stabilized in the central position of the must. At the same time, due to the difference in stress between the inner and outer fibers during the twisting process of the core-spun yarn, there is a phenomenon of fiber transfer between the inner and outer layers, and the two together make the core yarn spiral distribution. When the outer fibers are transferred to the inside of the yarn body, the core yarn will inevitably be pushed to the surface, resulting in core exposure problems. However, so far there is still a lack of systematic detection of the core quality of the core-spun yarn, and there is no systematic quality standard for the core-spun yarn. SUMMARY

[0005] The purpose of the present application is to overcome the above-mentioned deficiencies of the prior art, and to provide a method and device for detecting the core exposure rate of core-spun yarn.

[0006] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0007] The first purpose of the present application is to provide a method and device for detecting the core exposure rate of core-spun yarn, and the method is suitable for ring spinning core-spun yarn, comprising the following steps:

[0008] S1, yarn unwinding and feeding

[0009] The yarn tube of the produced ring spinning core-spun yarn is sleeved into the transverse unwinding mechanism, so that the fixed shaft of the yarn tube is a transverse free rotating shaft. The unwound yarn moves along the guide roller and is fed into the roller;

[0010] S2, image capture of the yarn to be tested

[0011] A camera is arranged in the area between the yarn guide wheel and the roller, which continuously takes pictures of the yarn between the yarn guide wheel and the roller, and numbers the pictures in sequence; meanwhile, according to the pulling speed v of the roller and the set photographing time t, the total length L of the yarn to be measured is calculated, the width L' of the yarn in the picture is measured, and the total area S of the yarn to be measured is calculated, with the following calculation formula:

[0012] L = v x t,

[0013] S = L' x L.

[0014] Wherein, v is in unit of m / min; t is in unit of min; L is in unit of m; L' is in unit of m; S is in unit of m 2 ;

[0015] S3, image processing and data analysis

[0016] The pictures with numbers obtained in step S2 are sequentially imported into a computer, black and white processing is performed, the area of the black part in each picture, i.e. the area of the core yarn exposed, is recognized, and the sum of all the black areas is calculated and recorded as S2.

[0017] S4, calculation formula

[0018] The core yarn exposure rate is the ratio k of the area of the core yarn exposed and the total area of the yarn, i.e.

[0019] Further, the camera includes two cameras, which are placed in parallel along the two sides of the yarn.

[0020] Further, the unwinding speed of the yarn is 30-50 m / min.

[0021] Further, the pixel of each camera is not less than 18 million, and the shutter speed is not less than 1 / 500 second.

[0022] Further, the two cameras are in continuous shooting mode, and the continuous shooting speed is 4-6 pictures per second.

[0023] Further, in step S3, according to the black and white processing result, the number of times of the core yarn exposure of the yarn to be measured is recorded as 1, 2, … n, the area of the core yarn exposed each time is approximately a parallelogram, and the length of the core yarn exposed each time is approximately the width L' of the yarn to be measured, and the width l of the core yarn exposed each time is measured. n The area S of the core yarn exposed each time is n L' x l. n .

[0024] The second object of the present application is to provide a device for detecting the core exposure rate of core-spun yarn by using the above method, comprising a transverse unwinding mechanism, a traction mechanism, a camera mechanism, a yarn suction air box and a computer, the transverse unwinding mechanism comprises a base, a support arm, a fixed shaft, an unwinding shaft and a telescopic spring, the support arm is arranged on the base, the end of the support arm is provided with the fixed shaft, the fixed shaft is rotatably provided with the unwinding shaft, the telescopic spring is installed on the unwinding shaft, the core-spun yarn bobbin is sleeved on the unwinding shaft, the telescopic spring is compressed to different degrees according to the size of the core-spun yarn bobbin, the traction mechanism comprises a guide roller and a roller, the yarn sleeved on the unwinding shaft is drawn into the roller by the guide roller, and the outgoing end of the roller is arranged at the air inlet of the yarn suction air box; the camera mechanism is arranged between the guide roller and the roller, the camera mechanism continuously shoots the yarn between the guide roller and the roller, and the pictures obtained by shooting are transmitted to the computer for processing.

[0025] Further, the traction mechanism further comprises a tension disc and a fixed plate, the guide roller, the roller and the tension disc are arranged in a straight line and are all arranged on the fixed plate, the roller is located directly below the guide roller, and the tension disc is arranged between the guide roller and the roller.

[0026] Further, the camera mechanism comprises a background plate and two cameras, and the two cameras are placed in parallel along the two sides of the yarn.

[0027] Further, the positions of the two cameras are 10-15 cm in height difference along the direction of the yarn.

[0028] Compared with the prior art, the present application has the following beneficial effects:

[0029] (1) The method for detecting the core exposure rate of core-spun yarn provided by the present application adopts transverse unwinding of the yarn of ring-spun core-spun yarn, since the ring core-spun yarn is formed by twisting the core yarn (filament) and the staple fiber together to achieve the covering effect, if the yarn is untwisted, the yarn structure is loose and damaged, and the core yarn is more likely to be exposed, so the traditional longitudinal unwinding cannot be used, and the transverse unwinding can better ensure the stability of the yarn during unwinding and the accuracy of the detection.

[0030] (2) The method provided by this invention involves setting up a camera mechanism in the area between the guide roller and the roller. The camera mechanism continuously captures images of the yarn between the guide roller and the roller. Since the yarn is a cylindrical body, single-sided shooting can only capture one side of the yarn, while the core yarn (filament) will be exposed on both sides of the yarn. To improve the accuracy of core yarn detection, two cameras are used to shoot at the same frequency. Images taken at the same time are marked with the same sequence number, and the images are arranged in order. The entire shooting process is continuous. In addition, the shooting area can be changed to different colored backgrounds according to the color of the core-spun yarn, which is helpful for distinguishing the color of the core yarn.

[0031] (3) The method provided by this invention is used to detect the covering quality of the outer fibers of ring-spun core-spun yarn on the core yarn, determine the proportion of the exposed core area to the overall yarn, and provide a new reference standard for the quality evaluation of core-spun yarn. Existing testing methods do not address the problem of core exposure in core-spun yarn. In current spinning technology, core exposure is unavoidable in ring-spun core-spun yarn. Core exposure not only affects the yarn structure but also its function due to structural damage. Furthermore, exposed core fibers can affect subsequent dyeing and finishing processes. Therefore, an accurate testing method is needed to evaluate the covering quality of core-spun yarn.

[0032] (4) The device for detecting the core exposure rate of core-spun yarn provided by the present invention has a simple structure, is easy to operate, and is beneficial to actual production. Attached Figure Description

[0033] Figure 1 A schematic diagram of the structure of a device for detecting the core exposure rate of core-spun yarn provided by the present invention;

[0034] Figure 2 This is a side view of the shooting area of ​​the present invention;

[0035] Figure 3 The images shown are of the exposed core of the core-spun yarn and are illustrated in the diagram for image processing.

[0036] In the diagram, 1. Lateral unwinding mechanism; 11. Base; 12. Support arm; 13. Fixed shaft; 14. Unwinding shaft; 15. Telescopic spring; 16. Core-spun yarn tube; 161. Yarn; 2. Traction mechanism; 21. Guide roller; 22. Roller; 23. Tension plate; 24. Fixed plate; 3. Camera mechanism; 31. Background plate; 32. Camera; 4. Yarn suction box; 5. Computer. Detailed Implementation

[0037] In order to make the objects, technical solutions and advantages of the present application clearer, the embodiments of the present application are described in detail below, examples of which are shown in the drawings, wherein the same or similar notations represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present application, and cannot be understood as a limitation of the present application.

[0038] Embodiment 1

[0039] The embodiment provides a method for detecting the core exposure rate of core-spun yarn.

[0040] The device shown in Figures 1-2 includes a transverse unwinding mechanism 1, a traction mechanism 2, a camera mechanism 3, a yarn suction air box 4 and a computer 5. The transverse unwinding mechanism 1 includes a base 11, a support arm 12, a fixed shaft 13, an unwinding shaft 14 and a telescopic spring 15. The support arm 12 is arranged on the base 11, the end of the support arm 12 is provided with the fixed shaft 13, the fixed shaft 13 is rotatably provided with the unwinding shaft 14, the telescopic spring 15 is installed on the unwinding shaft 14, the core-spun yarn tube 16 is sleeved on the unwinding shaft 14, the telescopic spring 15 is compressed to different degrees according to the size of the core-spun yarn tube 16, the spring provides a certain reaction force to the yarn tube after being compressed, which prevents the yarn tube from slipping due to external force and ensures that the yarn tube moves synchronously with the unwinding shaft; the traction mechanism 2 includes a guide roller 21 and a roller 22, the yarn 161 of the core-spun yarn tube sleeved on the unwinding shaft 14 is drawn into the feeding roller 22 by the guide roller 21, and the outgoing end of the roller 22 is arranged at the air inlet of the yarn suction air box 4; the camera mechanism 3 is arranged between the guide roller 21 and the roller 22, the camera mechanism 3 continuously shoots the yarn 161 between the guide roller 21 and the roller 22, and the pictures obtained by shooting are transmitted to the computer 5 for processing.

[0041] The core-spun yarn is spun on a ring spinning frame, the short fibers are wrapped outside the spun yarn or filament with a certain twist to form a core-spun yarn tube. The core-spun yarn tube is sleeved on the transverse unwinding mechanism to passively stabilize the output yarn, ensure the integrity of the core-spun yarn structure, prevent the yarn from untwisting and affect the accuracy of detection. The unwinding device of the traditional spun yarn detection system is longitudinal unwinding. Since the core yarn and the outer fiber are twisted together to form the core-sheath structure of the core-spun yarn, when the yarn untwists, the core yarn is more likely to be exposed from the main body of the yarn. Therefore, in order to ensure the stability of the core-spun yarn structure during unwinding and avoid the change of the twist, it is necessary to transversely unwind the yarn to avoid the change of the yarn structure before detection affecting the detection effect.

[0042] The transverse unwinding mode is passive unwinding, and the fixed shaft of the yarn tube is a transverse free rotating shaft. During detection, the yarn is unwound at the linear speed of the roller to avoid mutual friction and twisting shrinkage of the yarn during unwinding. The unwound yarn moves along the guide wheel 21 and is fed into the shooting area. The adjustable tension disc 23 ensures that the yarn always has a certain pre-tension and remains in a straight state.

[0043] A camera mechanism 3 is erected in the area between the guide wheel 21 and the roller 22. The camera mechanism 3 includes a background plate 31 and two cameras 32. The two cameras 32 are placed in parallel on both sides of the yarn 161, and the height difference between the two cameras is about 10 cm to ensure that the two cameras do not interfere with each other. Since the movement path of the core-spun yarn during shooting is up and down, a shutter speed of 1 / 500 seconds is used to keep the focus stable during shooting. The camera pixel is 18 million to ensure the clarity of the photo. The photographing frequency of the two cameras is the same, and the two sides of the core-spun yarn are shot respectively to ensure that each part of the core-spun yarn is shot.

[0044] In some embodiments, the back of each of the two cameras 32 is provided with a background plate 31. The background plate 31 can change color according to the color state of the yarn to facilitate the identification of the core yarn exposure condition and ensure that the shot picture is in the best state. Adjustable lights are installed on both sides of the shooting area to ensure the imaging state and clarity of the yarn.

[0045] After the core-spun yarn is led out of the shooting area, it is held by the roller below the shooting area. The stable traction of the yarn is realized by adjusting the roller speed, and the roller linear speed is set in the range of 30 m / min to 50 m / min.

[0046] Due to the small fineness of the yarn, in order to more clearly calculate the exposed area of the core yarn and make the exposed area closer to a parallelogram, the camera parameters are set to macro mode. In macro mode, the camera automatically adjusts the aperture size and focal length. In addition, the macro size can be adjusted appropriately according to the fineness of the yarn. In particular, the macro mode of the two cameras is set consistently, and the two cameras shoot two planes of the yarn respectively. A certain height difference is set between the two cameras to avoid interference.

[0047] In order to ensure the stability of the yarn movement state and considering the size and cost of the camera installation space, the unwinding speed of the yarn should not be too large. The yarn unwinding speed is controlled in the range of 30 m / min to 50 m / min, and the shutter speed is set to 1 / 500 to ensure the clarity of the picture. In order to ensure the continuity of the shot yarn, both cameras use continuous shooting mode, and the continuous shooting speed is 4 to 6 pictures per second.

[0048] Statistical analysis is performed on the images captured by two cameras, and the total length L of the core-spun yarn test can be calculated based on the roller speed and the shooting time.

[0049] Image processing is carried out on the captured images to identify the core yarn, mark the core yarn, record the number of times the core yarn of the yarn to be tested is exposed as 1, 2,... n. The area of each core yarn exposure is approximately a parallelogram, and the length of each core yarn exposure is approximately the width L' of the yarn to be tested. Measure the width l of each core yarn exposure. n , the area S of each core yarn exposure n = L'×l n .

[0050] As Figure 3 shown, calculate the area of the core yarn exposed from the yarn body through the pictures captured by the camera. Process the image and approximately regard the area where the core yarn is exposed as a parallelogram, calculate the area where the core yarn is exposed, and sum up the areas where all the core yarns are exposed. Since the colors of the core yarn and the outer wrapping fibers are different, perform black-and-white processing on the captured images, calculate the area of the black part in the pictures, and sum up all the black areas and denote it as S2.

[0051] S2 = L'×l1 + L'×l2 + L'×l3 + …… + L'×l n .

[0052] At the same time, according to the traction speed v of the roller and the set shooting duration t, calculate the total length L of the yarn to be tested, measure the width L' of the yarn in the picture, and the total area S of the yarn to be tested. The calculation formulas are as follows:

[0053] L = v×t,

[0054] S = L'×L.

[0055] Among them, the unit of v is m / min; the unit of t is min; the unit of l n is m; the unit of L is m; the unit of L' is m; the unit of S is m 2 ; the unit of S2 is m 2 ;

[0056] The calculation of the core yarn exposure rate of the core-spun yarn mainly includes the calculation of the total area S of the core-spun yarn to be tested and the calculation of the total area S2 of the core yarn exposed from the yarn to be tested. The ratio of S2 to S is the core yarn exposure rate of the core-spun yarn.

[0057] According to the test results of the core-spun yarn, it is stipulated that the exposure rate k < 15% is a high-quality core-spun yarn; 15% < k < 40% is an ordinary core-spun yarn; k > 40% is a low-quality core-spun yarn.

[0058] In some embodiments, the test results obtained by the detection method according to the present application can divide the core-spun yarn into three grades, and for high-quality core-spun yarn, defects caused by uneven dyeing can be avoided in the dyeing and finishing process. When low-quality core-spun yarn appears, the spinning process needs to be optimized to improve the covering effect. Secondly, according to the requirements of the dyeing and finishing process, high-quality core-spun yarn needs to be used to produce fabrics with smooth appearance, and ordinary core-spun yarn can be used to produce denim fabrics. The spun core-spun yarn can also be divided by detection standards, and different standards of core-spun yarn can be used to produce fabrics of different quality grades, and efficient use of core-spun yarn of various grades can bring greater benefits.

[0059] The above not involved, applicable to the prior art.

[0060] Although some specific embodiments of the present application have been described in detail by examples, those skilled in the art should understand that the above examples are only for illustration, not for limiting the scope of the present application, and those skilled in the art can make various modifications or supplements to the described specific embodiments or replace them with similar ways, but will not deviate from the direction of the present application or exceed the scope defined by the appended claims. Those skilled in the art should understand that any modification, equivalent replacement, improvement, etc. made to the above embodiments according to the technical essence of the present application shall be included in the protection scope of the present application.

Claims

1. A method of detecting the show-through of a core yarn, characterized in that, The method is suitable for ring spinning core-spun yarn and comprises the following steps: S1, transverse unwinding and feeding of the yarn The yarn tube of the produced ring spinning core-spun yarn is sleeved on the transverse unwinding mechanism, so that the fixed shaft of the yarn tube is a transverse free rotating shaft, the unwound yarn moves along the guide roller and is fed to the roller; S2, image capturing of the yarn to be measured A camera mechanism is erected in the area between the guide roller and the roller, the camera mechanism continuously photographs the yarn between the guide roller and the roller, the photographed pictures are sequentially numbered, the total length L of the yarn to be measured is calculated according to the pulling speed v of the roller and the set photographing time t, the width L' of the yarn in the measurement picture is measured, the total area S of the yarn to be measured is calculated, and the calculation formula is as follows: L = v × t, S = L' × L; wherein v is in units of m / min; t is in units of min; L is in units of m; L' is in units of m; S is in units of m 2 ; S3, image processing and data analysis The pictures with numbers obtained in step S2 are sequentially introduced into a computer, black and white processing is performed, the area of the black part in each picture, that is, the exposed area of the core yarn, is recognized, the sum of all the black areas is calculated and recorded as S2; S4, calculation formula The core yarn exposure ratio is the ratio k of the area of the core yarn exposed and the total area of the yarn, i.e.

2. The method of claim 1, wherein, The camera mechanism comprises two cameras, and the two cameras are placed in parallel on both sides of the yarn.

3. The method of claim 2, wherein, The unwinding speed of the yarn is 30-50 m / min.

4. The method of claim 2, wherein, The pixel of each camera is not less than 18 million, and the shutter speed is not less than 1 / 500 s.

5. The method of claim 4, wherein, The two cameras are in continuous shooting mode, and the continuous shooting speed is 4-6 pictures / s.

6. The method of claim 4, wherein, In step S3, according to the black and white processing result, the core yarn exposure times of the yarn to be measured are recorded as 1, 2, … n, the core yarn exposure area each time is approximately a parallelogram, the length of the core yarn exposure each time is approximately the width L' of the yarn to be measured, and the width l of the core yarn exposure each time is measured n The core yarn exposure area S each time is n = L' x l n .

7. A device for detecting the core exposure of a cored yarn using the method according to any one of claims 1 to 6, characterized in that The device comprises a transverse unwinding mechanism (1), a pulling mechanism (2), a camera mechanism (3), a yarn suction air box (4) and a computer (5), the transverse unwinding mechanism (1) comprises a base (11), a supporting arm (12), a fixed shaft (13), an unwinding shaft (14) and a telescopic spring (15), the supporting arm (12) is arranged on the base (11), the end of the supporting arm (12) is provided with the fixed shaft (13), the fixed shaft (13) is rotatably provided with the unwinding shaft (14), the telescopic spring (15) is installed on the unwinding shaft (14), the core-spun yarn tube (16) is sleeved on the unwinding shaft (14), the telescopic spring (15) is compressed to different degrees according to the size of the core-spun yarn tube (16), the pulling mechanism (2) comprises a guide roller (21) and a roller (22), the guide roller (21) pulls the yarn (161) of the core-spun yarn tube sleeved on the unwinding shaft (14) into the roller (22), and the outlet end of the roller (22) is arranged at the air inlet of the yarn suction air box (4); the camera mechanism (3) is arranged between the guide roller (21) and the roller (22), the camera mechanism (3) continuously photographs the yarn (161) between the guide roller (21) and the roller (22), and the photographed pictures are transmitted to the computer (5) for processing.

8. The apparatus of claim 7, wherein, The traction mechanism (2) further comprises a tension disc (23) and a fixed plate (24), the thread guide wheel (21), the roller (22) and the tension disc (23) are arranged in a straight line and are all arranged on the fixed plate (24), the roller (22) is located directly below the thread guide wheel (21), and the tension disc (23) is arranged between the thread guide wheel (21) and the roller (22).

9. The apparatus of claim 7, wherein, The camera mechanism (3) comprises a background plate (31) and two cameras (32), and the two cameras (32) are arranged in parallel on both sides of the yarn (161).

10. The apparatus of claim 9, wherein, The height difference between the positions of the two cameras is 10-15 cm in the yarn direction.

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