Method of controlling uniformity of fancy yarn face finish

Abstract

The application relates to the technical field of textiles, in particular to a fancy yarn surface uniformity treatment control method, which comprises the following steps: S1. fiber pretreatment; S2. fiber mixing; S3. airflow conveying monitoring; S4. roving; S5. twisting and yarn making; and S6. surface uniformity analysis. The application can accurately control the surface uniformity of the fancy yarn and keep the stability of product quality by the following steps: the fibers are sequentially subjected to preliminary mixing, multi-group mixing, and the mixing uniformity of the fibers is judged; the mixed fibers are subjected to airflow conveying; the airflow conveying flow rate is adjusted when the fibers deposit in the pipeline; the airflow conveying flow rate is corrected in real time during actual conveying; the uniformity of the twisting process is judged by calculating the variation coefficient of the roving; the fancy yarn is prepared; the surface image of the fancy yarn is obtained; whether the surface uniformity of the fancy yarn is qualified is judged; and a feedback signal is sent.

Description

Technical Field

[0001] This invention relates to the field of textile technology, and more specifically, to a method for controlling the uniformity of the nap of fancy yarns. Background Technology

[0002] In the modern textile industry, fancy yarns occupy a pivotal position due to their unique appearance and rich texture. From high-end fashion apparel fabrics to exquisite home textiles, the application of fancy yarns is ubiquitous, giving products a unique style and charm. As consumers' demand for personalized and diversified textiles continues to grow, the market demand for fancy yarns continues to rise.

[0003] Although the napped surface effect of fancy yarns brings many advantages to textile products, the problem of napped surface uniformity has always plagued the industry. Poor napped surface uniformity can lead to obvious differences in the appearance of the yarn, affecting the overall aesthetics and quality stability of the fabric. For example, when producing batches of napped fancy yarn fabrics, if the napped surface uniformity is inconsistent, the finished garments may have areas with dense napping and areas with sparse napping, which seriously affects the appearance consistency and commercial value of the product.

[0004] The existing Chinese patent application number 201910336810.7 discloses a method for producing knitted blended yarn. The method uses cotton fiber and viscose fiber as raw materials. After the two fibers are processed by the pre-processing of opening and cleaning, they are fed into a multi-compartment cotton blending machine in a blending ratio to achieve random mixing between them under the action of airflow. The two fibers are then subjected to vibration feeding and beating to form a spool to obtain a blended cotton spool. Then, a series of processes are carried out to obtain the desired knitted blended yarn.

[0005] However, the above-mentioned patent has the following problems: the solution uses airflow multiple times to achieve fiber transport and mixing, but the stability of airflow may be affected by a variety of factors. If the airflow is unstable, it may lead to uneven fiber transport and mixing, thereby affecting the uniformity of the product.

[0006] For example, Chinese patent application number 202411221642.4 discloses a linen-like fancy yarn and its preparation method. In the blending process, the integrity of the fibers and the uniformity of the mixture are ensured through pretreatment and adjustment of specific process parameters, thereby improving the overall performance and quality of the yarn. Moreover, the use of a blend of multiple lyocell fibers gives the yarn a unique texture and visual effect, meeting the market demand for new textiles.

[0007] However, the above-mentioned patent has the following problems: First, the solution does not provide further monitoring or adjustment means to ensure the uniformity of the yarn in the roving process, which may lead to uneven yarn linear density and cause uneven fabric surface in subsequent textile processing.

[0008] Second, this solution uses a blend of various lyocell fibers. Different lyocell fibers have significant differences in length and fineness. During the twisting process, longer and thicker fibers may tend to be distributed on the outer layer of the yarn, while shorter and thinner fibers are more likely to be concentrated inside the yarn. This will lead to uneven fiber distribution inside the yarn, thus affecting the uniformity of twisting. This solution does not mention twisting-related factors, which may lead to unstable yarn quality. Summary of the Invention

[0009] To overcome the shortcomings of the prior art, this invention provides a method for controlling the uniformity of the nap of fancy yarns, which can effectively solve the problems mentioned in the prior art.

[0010] The objective of this invention can be achieved through the following technical solution: a method for controlling the uniformity of the nap of fancy yarn, the method comprising the following steps: S1. Fiber pretreatment: obtaining the moisture regain of each fiber raw material and performing moisture regain balancing treatment on it.

[0011] S2. Fiber mixing: The fibers are initially mixed and then mixed in multiple batches in sequence, and the uniformity of the fiber mixing is judged.

[0012] S3. Airflow conveying monitoring: The mixed fibers are conveyed by airflow to determine whether the fibers are deposited in the pipeline. If deposits are found, the airflow conveying speed is adjusted and the airflow conveying speed is corrected in real time during actual conveying.

[0013] S4. Roving: The fiber bundle is stretched and thinned according to the draft ratio, and the drafted fibers are twisted to form roving.

[0014] S5. Twisting Yarn Making: Calculate the coefficient of variation of the roving, determine whether the uniformity of the twisting process is qualified, and then produce fancy yarn.

[0015] S6. Nail Surface Uniformity Analysis: Obtain the nap image of the fancy yarn, determine whether the nap surface uniformity of the fancy yarn is qualified, and then issue a feedback signal.

[0016] Preferably, the specific operation process of the fiber pretreatment is as follows: obtain the type of fiber raw material, denoted as each fiber raw material; match each fiber raw material with the corresponding moisture regain target value of each type of fiber raw material stored in the management database to obtain the moisture regain target value of each fiber raw material; measure the weight of each fiber raw material; add lubricant according to the weight of each fiber raw material in proportion; extract a sample of a set weight from each part of each fiber raw material; use a moisture meter to obtain the moisture regain of each part of each fiber raw material; and calculate the average value to obtain the moisture regain of each fiber raw material.

[0017] The moisture regain difference of each fiber material is obtained by subtracting the moisture regain of each fiber material from its target moisture regain value. A threshold for the moisture regain difference is set, and each fiber material whose moisture regain difference is greater than the set threshold is selected and recorded as each balanced fiber material. These fibers are then placed in a specific humidity environment for moisture regain balancing treatment.

[0018] Preferably, the specific operation process of fiber mixing is as follows: according to the preset defined moisture regain range, the pretreated fiber raw materials are grouped according to the moisture regain range and recorded as each group of fibers. The mixing time is determined according to the weight of each group of fibers, and a low-speed stirring and mixing device is used to perform preliminary mixing in groups. The pre-mixed groups of fibers are put into the main mixing device according to the preset formula ratio for multiple mixing to form a mixed fiber.

[0019] A fiber-mixed standard sample was prepared, and its light scattering was measured using a light scattering monitor. The light scattering intensity of the fiber-mixed standard sample at various angles was obtained and denoted as . , Indicates the first Numbering of each angle, According to the preset equal time interval principle, each detection time point is set in the multiple mixing processes. At each detection time point, light of a set wavelength is emitted to the fiber. The light scattering intensity of the fiber at each detection time point is measured by a detector at each angle. , Indicates the first The number of each detection time point, .

[0020] Preferably, the specific operation process for determining the uniformity of fiber mixing is as follows: based on the light scattering intensity of the fiber mixing standard sample at various angles... Light scattering intensity of fibers at various time points and angles Calculate the mixing uniformity of fibers at each detection time point. ,in Indicates the number of angles. This represents the average light scattering intensity of the fiber at each detection time point. The weighting factors, representing the light scattering intensity and the degree of light scattering intensity fluctuation, are expressed by the formula... Calculate the difference in fiber mixing uniformity over time. Indicates the first The mixing uniformity at each detection time point is assessed. If the difference in the uniformity of fiber mixing over time is positive, it indicates that the mixing process is progressing towards uniform mixing. Mixing continues until the uniformity reaches the preset ideal value. If the value is negative, it indicates a problem with the mixing process, and mixing needs to be stopped and the parameters of the mixing equipment adjusted.

[0021] Preferably, the specific operation process for determining whether fiber deposition occurs in the pipeline is as follows: multiple groups of fibers after mixing are recorded as mixed fibers, a set amount of mixed fibers are selected as fiber conveying samples, placed in the hopper of the pneumatic conveying equipment, the pneumatic conveying equipment is set and started according to the preliminary conveying flow rate determined by computer simulation, and the inlet flow rate and outlet flow rate of fiber conveying are obtained by installing flow monitoring devices at the inlet and outlet of the pneumatic conveying pipeline, the difference is calculated to obtain the fiber conveying flow rate difference value, and a fiber conveying flow rate difference threshold value is set. If the fiber conveying flow rate difference value is greater than or equal to the fiber conveying flow rate difference threshold value, it is determined that fiber deposition has occurred in the pipeline, and the pneumatic conveying flow rate needs to be adjusted.

[0022] Preferably, the specific operation process of adjusting the airflow conveying speed is as follows: with a fixed flow rate as the increase range, the airflow conveying speed is gradually increased, and the fiber conveying flow rate difference after each increase in flow rate is obtained in real time. When the fiber conveying flow rate difference is lower than the preset fiber conveying flow rate difference threshold, the corresponding airflow conveying speed is obtained and recorded as the suitable airflow conveying speed.

[0023] Preferably, the specific operation process for real-time correction of the airflow conveying velocity is as follows: adjust the airflow conveying equipment according to the appropriate airflow conveying velocity, set each position point in the airflow conveying pipeline according to the principle of equal spacing, convey the mixed fiber to the next process through airflow, obtain the airflow conveying velocity at each position point during the airflow conveying process, compare it with the appropriate airflow conveying velocity to obtain the airflow conveying velocity difference at each position point, and correct the airflow conveying velocity at each position point through the installed airflow adjustment device.

[0024] Preferably, the specific operation process of the roving is as follows: the fibers conveyed by the airflow are evenly fed into the drafting device of the roving frame through the fiber guiding device, the average fineness of the fibers is obtained by the fiber measuring instrument, the drafting ratio is obtained by dividing the required linear density of the roving by the average fineness of the fibers, and the drafting ratio of the drafting device is set accordingly, the fiber bundle is stretched and thinned, and the drafted fibers are twisted to form roving.

[0025] Randomly select roving samples from the twisted roving, fix one end of each sample to a chuck of a twist meter, start the twist meter, and rotate the movable chuck at a set speed to untwist each roving sample back to its initial untwisted state. Obtain the number of twists per unit length for each roving sample, and record it as the twist count of each roving sample. , Indicates the first The number of each roving sample, .

[0026] Preferably, the specific operation process of the twisting yarn making is as follows: calculating the coefficient of variation of the roving. The formula for calculating the coefficient of variation is: ,in This represents the average number of twists in the roving sample. To determine the number of roving samples, a coefficient of variation threshold is set. The coefficient of variation of the roving is compared with the coefficient of variation threshold. If the coefficient of variation of the roving is less than the coefficient of variation threshold, it means that the fluctuation of the roving twist in the yarn length direction meets the requirements and the uniformity of the twisting process is qualified. Conversely, it means that the uniformity of the twisting process is unqualified and the twisting equipment needs to be calibrated and re-twisted.

[0027] The obtained rovings are combined and then drafted and twisted again through a spinning machine to produce the required yarn, which is then shaped into fancy yarn according to design requirements.

[0028] Preferably, the specific analysis process for the uniformity analysis of the yarn surface is as follows: Acquire a yarn surface image of the fancy yarn, perform grayscale processing on it, set a grayscale threshold, separate the yarn fiber region and background region through binarization, divide the yarn fiber region into sub-regions, count the number of pixels in each sub-region, and simultaneously obtain the total number of pixels in the yarn surface image. Calculate the ratio of the counted number of pixels in each sub-region to the total number of pixels to obtain the yarn fiber coverage density of each sub-region, denoted as . , Indicates the first The sub-region numbering, Calculate the uniformity of the nap of fancy yarns. ,in This indicates the number of sub-regions. A uniformity threshold is set, and the uniformity of the fancy yarn's surface is compared with the uniformity threshold. If the uniformity of the fancy yarn's surface is greater than or equal to the uniformity threshold, it means that the uniformity of the fancy yarn's surface is qualified; otherwise, it means that the uniformity of the fancy yarn's surface is unqualified. Feedback is provided on the qualification level of the fancy yarn's surface uniformity.

[0029] Compared with the prior art, the embodiments of the present invention have at least the following advantages or beneficial effects: First, the present invention performs preliminary mixing and multiple mixing of fibers in sequence, and judges the uniformity of fiber mixing. Different fibers have different physical and chemical properties. Preliminary mixing and multiple mixing can make these fibers evenly distributed in the yarn, avoiding local performance differences caused by fiber aggregation.

[0030] Second, this invention uses airflow to transport mixed fibers. When fibers deposit in the pipe, the airflow speed is adjusted, and the airflow speed is corrected in real time during actual transport. By adjusting the airflow speed when deposits occur, the fibers can be resuspended in the airflow to avoid blockage. The real-time correction of the airflow speed can adjust the transport state of the fibers according to these changes, so that the fibers always maintain a stable suspension and movement state, ensuring uniform transport.

[0031] Third, this invention determines whether the uniformity of the twisting process is qualified by calculating the coefficient of variation of the roving, and then produces fancy yarn. Twisting is the process of making the fibers in the yarn hold together. The uniformity of twist directly affects the uniformity of the yarn structure. By calculating the coefficient of variation to determine the uniformity of the twisting process, it can be ensured that the twist distribution of the yarn is uniform in the length direction, so that the fibers are arranged neatly and tightly in the yarn, ensuring the stability and uniformity of the yarn structure.

[0032] Fourth, this invention obtains a surface image of fancy yarn, determines whether the surface uniformity of the fancy yarn is qualified, and then sends a feedback signal. By obtaining the surface image, the distribution of fibers on the yarn surface can be observed intuitively, ensuring that the produced fancy yarn meets the quality standards. Attached Figure Description

[0033] The present invention will be further described with reference to the accompanying drawings, but the embodiments in the drawings do not constitute any limitation on the present invention. For those skilled in the art, other drawings can be obtained based on the following drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the method flow of the present invention.

[0035] Figure 2 for Figure 1 A flowchart of step S1.

[0036] Figure 3 This is a flowchart of the process judgment of the present invention. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Please see Figure 1 As shown, the present invention provides a method for controlling the uniformity of the nap of fancy yarn. The method includes the following steps: S1. Fiber pretreatment: obtaining the moisture regain of each fiber raw material and performing moisture regain balancing treatment on it.

[0039] Please see Figure 2 As shown, the specific operation process of the fiber pretreatment is as follows: The types of fiber raw materials are obtained and denoted as each fiber raw material. Each fiber raw material is matched with the corresponding moisture regain target values ​​stored in the management database to obtain the moisture regain target value for each fiber raw material. The weight of each fiber raw material is measured. Lubricant is added proportionally according to the weight of each fiber raw material. Samples of a set weight are extracted from each part of each fiber raw material. The moisture regain of each part of each fiber raw material is obtained using a moisture meter. The average value is calculated to obtain the moisture regain of each fiber raw material. This provides an accurate basis for subsequent moisture regain balancing treatment. Without accurate measurement of the moisture regain of each part, the moisture regain balancing treatment may be insufficient or excessive.

[0040] The moisture regain difference of each fiber raw material is obtained by subtracting its target moisture regain value from its actual moisture regain value. A threshold for the moisture regain difference is set, and fiber raw materials with a moisture regain difference greater than the set threshold are selected and recorded as balanced fiber raw materials. These are then placed in a specific humidity environment for moisture regain balancing treatment. Throughout the entire production process, the moisture regain of all fiber raw materials remains within a suitable range, which helps to ensure the quality stability of the product between batches.

[0041] It should be noted that the specific analysis method for the moisture regain balancing process is as follows: according to the preset equal time interval principle, several time points are set in the moisture regain balancing process, the moisture regain of each balancing fiber raw material at each time point is obtained, and the difference between the moisture regain target value of each fiber raw material and the moisture regain target value of each balancing fiber raw material at each time point is obtained. When the moisture regain difference of a certain balancing fiber raw material at a certain time point is less than or equal to the set moisture regain difference threshold, it is determined that the balancing process of that fiber raw material is completed, thereby completing the balancing process of each balancing fiber raw material.

[0042] S2. Fiber mixing: The fibers are initially mixed and then mixed in multiple batches in sequence, and the uniformity of the fiber mixing is judged.

[0043] The specific operation process of fiber mixing is as follows: according to the preset moisture regain range, the pretreated fiber raw materials are grouped according to each moisture regain range and recorded as each group of fibers. The mixing time is determined according to the weight of each group of fibers, and a low-speed stirring and mixing device is used to perform preliminary mixing of the groups. The pre-mixed groups of fibers are then put into the main mixing device according to the preset formula ratio for multiple mixing to form a group of mixed fibers. Grouping can group fiber raw materials with similar moisture regain characteristics together, which helps to better control the uniformity of mixing in the subsequent mixing process, because fiber raw materials with similar moisture regain are more likely to blend together during mixing, avoiding unevenness caused by excessive differences in moisture regain.

[0044] A fiber-mixed standard sample was prepared, and its light scattering was measured using a light scattering monitor. The light scattering intensity of the fiber-mixed standard sample at various angles was obtained and denoted as . , Indicates the first Numbering of each angle, According to the preset equal time interval principle, each detection time point is set in the multiple mixing processes. At each detection time point, light of a set wavelength is emitted to the fiber. The light scattering intensity of the fiber at each detection time point is measured by a detector at each angle. , Indicates the first The number of each detection time point, Light scattering measurements can reflect the structure and distribution of fibers at different angles. By measuring standard samples, a light scattering intensity model under an ideal mixed state can be established.

[0045] The specific procedure for determining the uniformity of fiber mixing is as follows: based on the light scattering intensity of the fiber mixing standard sample at various angles... Light scattering intensity of fibers at various time points and angles Calculate the mixing uniformity of fibers at each detection time point. ,in Indicates the number of angles. This represents the average light scattering intensity of the fiber at each detection time point. The weighting factors, representing the light scattering intensity and the degree of light scattering intensity fluctuation, are expressed by the formula... Calculate the difference in fiber mixing uniformity over time. Indicates the first The mixing uniformity at each detection time point is determined by the following: if the difference in the mixing uniformity of the fibers over time is positive, it indicates that the mixing process is progressing towards uniform mixing, and mixing continues until the mixing uniformity reaches the preset ideal value. If the difference is negative, it indicates a problem with the mixing process, and mixing needs to be stopped and the parameters of the mixing equipment adjusted. By calculating the difference in the mixing uniformity over time, the direction of the mixing process can be determined. A positive value indicates progress towards uniform mixing, while a negative value indicates a problem with the mixing process.

[0046] It should be noted that in the formula for the uniformity of fiber mixing at each testing time point, This represents the absolute difference between the light scattering intensity of the actual fiber and the light scattering intensity of the standard sample at various angles. The larger the deviation, the worse the uniformity of the actual fiber mixture. The formula is calculated as the reciprocal of the mean square error. The mean square error is used to measure the dispersion of a set of data. Here, the mean square error of light scattering intensity reflects the fluctuation of light scattering intensity of the fiber at various angles. Taking the reciprocal of the mean square error means that the smaller the difference between the actual light scattering intensity of the fiber at various angles and the average value, the larger this part is, and the greater its contribution to the overall result in the formula. That is, it is more conducive to improving the calculated mixing uniformity value. This is consistent with the actual situation, because a more stable light scattering intensity corresponds to better fiber mixing uniformity.

[0047] It should be noted that, in one specific embodiment, It can be set to 0.6. The value can be set to 0.4. Light scattering intensity is directly related to the structural inhomogeneity within the fiber. If the fiber mixture is uneven, different scattering centers will exist in different regions, leading to significant changes in the overall light scattering intensity. The degree of fluctuation in light scattering intensity reflects local inhomogeneity more. Although local inhomogeneity is also part of the degree of mixing uniformity, it may only be a local deviation compared to the overall light scattering intensity. Therefore, the weight corresponding to light scattering intensity is greater.

[0048] It should be noted that the specific operation method for adjusting the parameters of the mixing equipment is as follows: adjust the mixing mode of the main mixing equipment to intermittent stirring, select each intermittent time interval for testing, keep other mixing conditions unchanged in each test, test the uniformity of each fiber sample after mixing, and select the intermittent time interval corresponding to the fiber sample with the highest uniformity to adjust the mixing frequency of the main mixing equipment; allowing the raw materials to have a certain time for self-adjustment and redistribution when stirring stops helps to improve the mixing uniformity.

[0049] S3. Airflow conveying monitoring: The mixed fibers are conveyed by airflow to determine whether the fibers are deposited in the pipeline. If deposits are found, the airflow conveying speed is adjusted and the airflow conveying speed is corrected in real time during actual conveying.

[0050] The specific operation process for determining whether fiber deposition has occurred in the pipeline is as follows: Multiple groups of fibers after mixing are recorded as mixed fibers. A set amount of mixed fibers is selected as a fiber transport sample and placed in the hopper of the pneumatic conveying equipment. The pneumatic conveying equipment is set and started according to the initial conveying flow rate determined by computer simulation. Flow monitoring devices are installed at the inlet and outlet of the pneumatic conveying pipeline to obtain the inlet flow rate and outlet flow rate of the fiber transport. The difference is calculated to obtain the fiber transport flow rate difference value. A fiber transport flow rate difference threshold is set. If the fiber transport flow rate difference value is greater than or equal to the fiber transport flow rate difference threshold, it is determined that fiber deposition has occurred in the pipeline, and the pneumatic conveying flow rate needs to be adjusted. This allows for timely detection of fiber deposition in the pipeline, preventing further deterioration of the deposition problem and thus preventing more serious problems such as pipeline blockage.

[0051] The specific operation process of adjusting the airflow conveying speed is as follows: gradually increase the airflow conveying speed with a fixed speed as the increment, and obtain the fiber conveying flow rate difference after each speed increase in real time. When the fiber conveying flow rate difference is lower than the preset fiber conveying flow rate difference threshold, obtain the corresponding airflow conveying speed and record it as the suitable airflow conveying speed. Gradually increasing the airflow conveying speed with a fixed speed as the increment can systematically change the conveying conditions to find a suitable airflow conveying speed and ensure the efficiency and quality of fiber conveying.

[0052] The specific operation process for real-time correction of the airflow velocity is as follows: the airflow conveying equipment is adjusted according to the appropriate airflow velocity, and each position point is set in the airflow conveying pipeline according to the principle of equal spacing. The mixed fibers are conveyed to the next process by airflow. The airflow velocity at each position point is obtained during the airflow conveying process, and it is compared with the appropriate airflow velocity to obtain the airflow velocity difference at each position point. The airflow velocity at each position point is corrected by the installed airflow adjustment device. This makes the fiber conveying conditions in the entire pipeline more uniform and avoids fiber deposition or uneven conveying caused by local abnormal flow velocity.

[0053] S4. Roving: The fiber bundle is stretched and thinned according to the draft ratio, and the drafted fibers are twisted to form roving.

[0054] The specific operation process of roving is as follows: the fibers conveyed by the airflow are evenly fed into the drafting device of the roving frame through the fiber guiding device. The average fineness of the fibers is obtained by the fiber measuring instrument. The drafting ratio is obtained by dividing the required linear density of the roving by the average fineness of the fibers. The drafting ratio of the drafting device is then set to stretch and thin the fiber bundle. The drafted fibers are then twisted to form roving. The drafting ratio directly affects the fineness of the roving. By accurately calculating and setting the drafting ratio, the linear density of the produced roving can meet the expected requirements, ensuring the stability of product quality, meeting the requirements of subsequent processes (such as the spinning process), and improving the efficiency and product qualification rate of the entire spinning production process.

[0055] Randomly select roving samples from the twisted roving, fix one end of each sample to a chuck of a twist meter, start the twist meter, and rotate the movable chuck at a set speed to untwist each roving sample back to its initial untwisted state. Obtain the number of twists per unit length for each roving sample, and record it as the twist count of each roving sample. , Indicates the first The number of each roving sample, The number of twists directly affects the strength, elasticity, and other properties of roving. By measuring the number of twists, it is possible to determine whether the twisting process meets the requirements, and then adjust and optimize the twisting process to ensure the stability of roving quality and ensure that the roving can operate normally in subsequent processing steps. For example, in the spinning process, the appropriate number of twists of the roving is necessary to ensure that the drafting and twisting of the spinning process can proceed smoothly.

[0056] S5. Twisting Yarn Making: Calculate the coefficient of variation of the roving, determine whether the uniformity of the twisting process is qualified, and then produce fancy yarn.

[0057] The specific operation process of twisting yarn is as follows: calculate the coefficient of variation of the roving. The formula for calculating the coefficient of variation is: ,in This represents the average number of twists in the roving sample. A threshold for the coefficient of variation (COP) is set for the number of roving samples. The COP of the roving is compared with the COP threshold. If the COP is less than the COP, it means that the fluctuation of the roving twist in the yarn length direction meets the requirements and the uniformity of the twisting process is qualified. Conversely, if the COP is less than the COP, it means that the uniformity of the twisting process is unqualified and the twisting equipment needs to be calibrated and re-twisted. If the COP is less than the COP, it means that the uniformity of the twisting meets the requirements and the product quality meets the standard in terms of twist uniformity, and it can proceed to the next process. If the COP is greater than the COP, this quantitative evaluation method can accurately identify potential problems with the twisting equipment, thereby allowing for targeted calibration of the twisting equipment, preventing unqualified products from entering subsequent processes, and improving the overall quality of the yarn.

[0058] It should be noted that the formula for the coefficient of variation of roving is obtained by summing the squared values ​​of the twist deviations of each roving sample. This reflects the dispersion of the number of twists of all samples relative to the mean. The greater the dispersion, the greater the difference between samples. Dividing this by the number of samples... ,Right now The variance of the sample is obtained, and the standard deviation is obtained by taking the square root of the variance. This can more intuitively reflect the dispersion of the data. By dividing the standard deviation by the mean, the coefficient of variation is obtained. The coefficient of variation is a relative indicator that eliminates the influence of data units, allowing the dispersion between data of different orders or units to be compared. The smaller the coefficient of variation, the more stable the roving twist and the better the uniformity. Conversely, the larger the coefficient of variation, the greater the fluctuation of the roving twist and the worse the uniformity.

[0059] The obtained rovings are combined and then drafted and twisted again through a spinning machine to produce the required yarn. According to the design requirements, fancy yarn is formed. In terms of yarn quality, the re-drafting and twisting can make the fineness of the yarn more accurately meet the design requirements, improve the strength, elasticity and other properties of the yarn, and reduce the unevenness of the yarn, making the yarn appearance more uniform and smooth and reducing defects.

[0060] S6. Nail Surface Uniformity Analysis: Obtain the nap image of the fancy yarn, determine whether the nap surface uniformity of the fancy yarn is qualified, and then issue a feedback signal.

[0061] The specific analysis process for the uniformity analysis of the yarn surface is as follows: Obtain the yarn surface image of the fancy yarn, perform grayscale processing, set a grayscale threshold, separate the fiber region and background region through binarization, divide the fiber region into sub-regions, count the number of pixels in each sub-region, and simultaneously obtain the total number of pixels in the yarn surface image. Calculate the ratio of the counted pixels in each sub-region to the total number of pixels to obtain the fiber coverage density of each sub-region, denoted as . , Indicates the first The sub-region numbering, Calculate the uniformity of the nap of fancy yarns. ,in This indicates the number of sub-regions, sets a uniformity threshold, and compares the uniformity of the fancy yarn's surface with this threshold. If the uniformity is greater than or equal to the threshold, the yarn is considered to be of acceptable quality; otherwise, it is considered unacceptable. Feedback is provided on the acceptable level of uniformity. The distribution density of fibers in each sub-region is accurately described in data form, facilitating comparisons between different sub-regions and providing fundamental data for calculating uniformity. By combining the fiber coverage density of each sub-region, the uniformity of the fancy yarn's surface is calculated. If the uniformity is acceptable, the product meets the requirements and can proceed to the next process or be released to the market. If it is unacceptable, the production process can be adjusted promptly, such as adjusting the fiber distribution or spinning process, to improve product quality.

[0062] It should be noted that in the formula for the uniformity of the nap of fancy yarn, Indicates the first The relative deviation of the wool fiber coverage density of each sub-region from the average coverage density reflects the degree to which the wool fiber coverage density of that sub-region deviates from the overall average level. Furthermore, it is standardized based on the average coverage density to facilitate comparison between different data. Then, the square root of the average of the above relative deviations is taken and the reciprocal is taken to calculate the variance of the wool fiber coverage density. The larger the value obtained after taking the reciprocal, the more concentrated the data is around the average value, that is, the more uniform the wool fiber coverage density of each sub-region.

[0063] This invention involves sequentially performing preliminary mixing and multiple mixing of fibers, assessing the uniformity of fiber mixing, and then conveying the mixed fibers via airflow. When fiber deposition occurs within the pipe, the airflow rate is adjusted, and real-time correction is performed during actual conveying. By calculating the coefficient of variation of the roving, the uniformity of the twisting process is determined, thereby producing fancy yarn. The fabric surface image of the fancy yarn is obtained, and its uniformity is assessed, triggering a feedback signal. This allows for precise control of the fabric surface uniformity of the fancy yarn, maintaining product quality stability.

[0064] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention, which are still covered within the protection scope of the present invention.

Claims

1. A method for controlling the uniformity of the napped surface of fancy yarns, characterized in that, Includes the following steps: S1. Fiber pretreatment: Obtain the moisture regain of each fiber raw material and perform moisture regain balancing treatment on it; S2. Fiber mixing: The fibers are initially mixed and then mixed in multiple batches in sequence, and the uniformity of the fiber mixing is judged. The specific operation process of fiber mixing is as follows: According to the preset range of moisture regain, the pretreated fiber raw materials are grouped according to the range of moisture regain and recorded as each group of fibers. The mixing time is determined according to the weight of each group of fibers, and a low-speed stirring and mixing device is used to perform preliminary mixing in each group. The pre-mixed groups of fibers are then put into the main mixing device according to the preset formula ratio for multiple mixing to form a mixed fiber. A fiber-mixed standard sample was prepared, and its light scattering was measured using a light scattering monitor. The light scattering intensity of the fiber-mixed standard sample at various angles was obtained and denoted as . , Indicates the first Numbering of each angle, According to the preset equal time interval principle, each detection time point is set in the multiple mixing processes. At each detection time point, light of a set wavelength is emitted to the fiber. The light scattering intensity of the fiber at each detection time point is measured by a detector at each angle. , Indicates the first The number of each detection time point, ; S3. Airflow conveying monitoring: The mixed fibers are conveyed by airflow to determine whether the fibers are deposited in the pipeline. If deposits are found, the airflow conveying speed is adjusted and the airflow conveying speed is corrected in real time during actual conveying. S4. Roving: The fiber bundle is stretched and thinned according to the draft ratio, and the drafted fibers are twisted to form roving; S5. Twisting yarn making: Calculate the coefficient of variation of the roving, determine whether the uniformity of the twisting process is qualified, and then produce fancy yarn; S6. Nail surface uniformity analysis: Obtain the nap image of fancy yarn, determine whether the nap surface uniformity of fancy yarn is qualified, and then issue a feedback signal. The specific operation process for determining the uniformity of fiber mixing is as follows: Based on the light scattering intensity of the fiber-mixed standard sample at various angles Light scattering intensity of fibers at various time points and angles Calculate the mixing uniformity of fibers at each detection time point. ,in Indicates the number of angles. This represents the average light scattering intensity of the fiber at each detection time point. Weighting factor representing light scattering intensity The weighting factor for the degree of light scattering intensity fluctuation is expressed by the formula. Calculate the difference in fiber mixing uniformity over time. Indicates the first The mixing uniformity at each detection time point is assessed. If the difference in the uniformity of fiber mixing over time is positive, it indicates that the mixing process is progressing towards uniform mixing. Mixing continues until the uniformity reaches the preset ideal value. If the value is negative, it indicates a problem with the mixing process, and mixing needs to be stopped and the parameters of the mixing equipment adjusted. The specific procedure for determining whether fiber deposition has occurred inside the pipe is as follows: The fibers after multiple mixing processes are recorded as mixed fibers. A set amount of mixed fibers is selected as a fiber conveying sample and placed in the hopper of the pneumatic conveying equipment. The pneumatic conveying equipment is set and started according to the initial conveying flow rate determined by computer simulation. By installing flow monitoring devices at the inlet and outlet of the pneumatic conveying pipeline, the inlet flow rate and outlet flow rate of fiber conveying are obtained. The difference is calculated to obtain the fiber conveying flow rate difference value. A fiber conveying flow rate difference threshold is set. If the fiber conveying flow rate difference value is greater than or equal to the fiber conveying flow rate difference threshold, it is determined that fiber has deposited in the pipeline and the pneumatic conveying flow rate needs to be adjusted. The specific analysis process for the uniformity analysis of the textured surface is as follows: A surface image of the fancy yarn is acquired and converted to grayscale. A grayscale threshold is set, and the fiber region and background region are separated through binarization. The fiber region is divided into sub-regions, and the number of pixels in each sub-region is counted. Simultaneously, the total number of pixels in the surface image is obtained. The ratio of the number of pixels in each sub-region to the total number of pixels is calculated to obtain the fiber coverage density of each sub-region, denoted as . , Indicates the first The sub-region numbering, Calculate the uniformity of the nap of fancy yarn. ,in This indicates the number of sub-regions. A uniformity threshold is set, and the uniformity of the fancy yarn's surface is compared with the uniformity threshold. If the uniformity of the fancy yarn's surface is greater than or equal to the uniformity threshold, it means that the uniformity of the fancy yarn's surface is qualified; otherwise, it means that the uniformity of the fancy yarn's surface is unqualified. Feedback is provided on the qualification level of the fancy yarn's surface uniformity.

2. The method for controlling the uniformity of the nap of fancy yarn according to claim 1, characterized in that: The specific operation process of the fiber pretreatment is as follows: The types of fiber raw materials are identified and denoted as each fiber raw material. Each fiber raw material is matched with the corresponding moisture regain target values ​​stored in the management database to obtain the moisture regain target value of each fiber raw material. The weight of each fiber raw material is measured. Lubricant is added in proportion according to the weight of each fiber raw material. Samples of a set weight are extracted from each part of each fiber raw material. The moisture regain of each part of each fiber raw material is obtained using a moisture meter. The average value is then used to obtain the moisture regain of each fiber raw material. The moisture regain difference of each fiber material is obtained by subtracting the moisture regain of each fiber material from its target moisture regain value. A threshold for the moisture regain difference is set, and each fiber material whose moisture regain difference is greater than the set threshold is selected and recorded as each balanced fiber material. These fibers are then placed in a specific humidity environment for moisture regain balancing treatment.

3. The method for controlling the uniformity of the nap of fancy yarn according to claim 1, characterized in that: The specific operation process for adjusting the airflow delivery velocity is as follows: With a fixed flow rate as the increment, the airflow rate is gradually increased, and the fiber conveying flow rate difference after each increase is obtained in real time. When the fiber conveying flow rate difference is lower than the preset fiber conveying flow rate difference threshold, the corresponding airflow rate is obtained and recorded as the suitable airflow rate.

4. The method for controlling the uniformity of the nap of fancy yarn according to claim 3, characterized in that: The specific operation process for real-time correction of the airflow velocity is as follows: Adjust the airflow conveying equipment according to the appropriate airflow velocity, set each position point in the airflow conveying pipeline according to the principle of equal distance, and convey the mixed fiber to the next process through airflow. Obtain the airflow velocity at each position point during the airflow conveying process, compare it with the appropriate airflow velocity to obtain the airflow velocity difference at each position point, and then correct the airflow velocity at each position point through the installed airflow adjustment device.

5. The method for controlling the uniformity of the nap of fancy yarn according to claim 1, characterized in that: The specific operation process for the roving is as follows: The fibers delivered by the airflow are evenly fed into the drafting device of the roving frame through the fiber guiding device. The average fineness of the fibers is obtained by the fiber measuring instrument. The drafting ratio is obtained by dividing the required linear density of the roving by the average fineness of the fibers. The drafting ratio of the drafting device is then set to stretch and thin the fiber bundle. The drafted fibers are then twisted to form roving. Randomly select roving samples from the twisted roving, fix one end of each sample to a chuck of a twist meter, start the twist meter, and rotate the movable chuck at a set speed to untwist each roving sample back to its initial untwisted state. Obtain the number of twists per unit length for each roving sample, and record it as the twist count of each roving sample. , Indicates the first The number of each roving sample, .

6. The method for controlling the uniformity of the nap of fancy yarn according to claim 5, characterized in that: The specific operation process of twisting yarn is as follows: Calculate the coefficient of variation of roving The formula for calculating the coefficient of variation is: ,in This represents the average number of twists in the roving sample. For the number of roving samples, a coefficient of variation threshold is set. The coefficient of variation of the roving is compared with the coefficient of variation threshold. If the coefficient of variation of the roving is less than the coefficient of variation threshold, it means that the fluctuation of the roving twist in the yarn length direction meets the requirements and the uniformity of the twisting process is qualified. Conversely, it means that the uniformity of the twisting process is unqualified and the twisting equipment needs to be calibrated and re-twisted. The obtained rovings are combined and then drafted and twisted again through a spinning machine to produce the required yarn, which is then shaped into fancy yarn according to design requirements.

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