System and method for fabric quality control using tension control unit in circular knitting machine

Abstract

The present invention discloses a system (100) and method (400) for dynamically adjusting fabric tension in a circular knitting machine (102) to enhance defect detection during manufacturing process. The system uses either a fabric spreader or a brake shape alteration mechanism for adjusting the tension of the fabric during production. The system integrates cameras (110) and optimized lighting unit (108) for real-time defect identification and comprises a fabric processing unit (114) for image processing, analysis, or data logging. By addressing limitations in existing solutions, the invention reduces fabric wastage, improves quality control, and enhances productivity without disrupting machine operations.

Description

System and method for fabric quality control using tension control unit in circular knitting machine

[0001] The field of invention generally relates to fabric quality control during fabric formation in a circular knitting machine. More specifically, it relates to a system and method for intentionally altering fabric tension and / or fabric geometry during operation of the circular knitting machine in order to reveal fabric defects that are otherwise not visible under normal tension conditions.

[0002] Quality control in fabric manufacturing, particularly for knitted fabrics, is critical to ensure minimal wastage, improve overall manufacturing efficiency, and maintain product standards. Defects associated with elastic yarns such as Lycra spandex, or elastane are hard to detect during production because such defects remain visually hidden when the fabric is maintained under uniform or steady-state tension. This often leads to significant material losses when entire rolls are rejected after inspection.

[0003] Currently, existing systems do not succeed in reliably detecting subtle or hidden defects during knitting process itself, particularly those that require changes in fabric tension for visibility.

[0004] Existing approaches generally face limitations in reliably detecting subtle or latent fabric defects during the knitting process itself, particularly defects that become visible only when the fabric is presented under altered tension or geometry conditions.

[0005] In other existing systems, fabric is inspected either after production or under a single, steady tension condition during production. However, defects only become apparent when the fabric is relaxed, stretched, or otherwise presented under a different tension or geometry than that used during normal knitting. As a result, such defects are often discovered only after the fabric roll is completed, leading to rejection of large quantities of fabric, increased wastage, and additional reprocessing costs.

[0006] Manual inspection, while common, is labor-intensive, error-prone, and requires stopping the machine, disrupting productivity.

[0007] The inability of current systems to dynamically adjust the fabric tension during production leads to certain types of defects being noticed only after the entire roll is completed.

[0008] Thus, in lighting unit of the above discussion, it is implied that there is need for a system and method for a non-intrusive, in-process inspection approach that enables detection of otherwise hidden defects during fabric formation, without requiring removal of the fabric from the machine or significant disruption to the knitting process, which is reliable, cost-effective, and does not suffer from the problems discussed above.Object of Invention

[0009] The principal object of this invention is to provide a system and method for fabric quality control in a circular knitting machine.

[0010] A further object of the invention is to provide the system and method for intentionally and temporarily altering fabric tension and / or fabric geometry during fabric formation to enhance visibility of defects.

[0011] Another object of the invention is to detect defects that are otherwise not visible under normal knitting tension, including defects associated with elastic yarns such as Lycra.

[0012] Another object of the invention is to reduce material wastage by identifying defects early during production stage.

[0013] Another object of the invention is to minimize machine stoppage for defect inspection, thereby increasing productivity.

[0014] Another object of the invention is to enable enhanced defect visibility using a combination of lighting units and fabric tension variation.

[0015] Another object of the invention is to improve detection of hard-to-detect Lycra defects without manual relaxation of the fabric.

[0016] Another object of the invention is to enhance the defect detection process using shape-altering fabric spreaders and dynamic clamping mechanisms.

[0017] Another object of the invention is to provide a robust inspection system that improves quality control while optimizing operational efficiency.

[0018] Another object of the invention is to provide a flexible inspection system that may operate with or without sensors, closed-loop control, artificial intelligence, or communication synchronization.

[0019] Another object of the invention is to provide a system that can be retrofitted onto existing circular knitting machines with minimal modification.

[0020] This invention is illustrated in the accompanying drawings, throughout which, like reference letters indicate corresponding parts in the various figures.

[0021] The embodiments herein will be better understood from the following description with reference to the drawings, in which:Fig. 1

[0022] depicts / illustrates a system for fabric quality control using a tension control unit in a circular knitting machine, in accordance with an embodiment of the present disclosure;Fig. 2

[0023] depicts / illustrates a block diagram of a fabric processing unit, in accordance with an embodiment of the present disclosure;Fig. 3

[0024] depicts / illustrates exemplary embodiments of the tension control unit in the open-width circular knitting machine, in accordance with an embodiment of the present disclosure;Fig. 3b

[0025] depicts / illustrates exemplary embodiments of the tension control unit in the open-width circular knitting machine, in accordance with an embodiment of the present disclosure;Fig. 3c

[0026] depicts / illustrates exemplary embodiments of the tension control unit in the tubular circular knitting machine, in accordance with an embodiment of the present disclosure;Fig.3d

[0027] depicts / illustrates exemplary embodiments of the tension control unit in the tubular circular knitting machine, in accordance with an embodiment of the present disclosure;Fig. 3e

[0028] depicts / illustrates exemplary embodiments of the tension control unit in the tubular circular knitting machine, in accordance with an embodiment of the present disclosure;Fig. 3f

[0029] exemplary embodiments of the tension control unit in the tubular circular knitting machine, in accordance with an embodiment of the present disclosure; andFig. 4

[0030] illustrates a method for fabric quality control using a tension control unit in a circular knitting machine, in accordance with an embodiment of the present disclosure.Statement of Invention

[0031] The present invention discloses a system and method for dynamically adjusting fabric tension in a circular knitting machine to enhance defect detection during manufacturing process. The system uses either a fabric spreader or a brake shape alteration mechanism for adjusting the tension of the fabric during production. The system integrates cameras and optimized lighting unit for real-time defect identification and may optionally comprise a fabric processing unit for image processing, logging, or automated analysis. By addressing limitations in existing solutions, the invention reduces fabric wastage, improves quality control, and enhances productivity without disrupting machine operations.Detailed Description

[0032] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and / or detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.

[0033] The present invention discloses a system and method for dynamically adjusting fabric tension in a circular knitting machine to enhance defect detection during manufacturing process. The system uses either a fabric spreader or a brake shape alteration mechanism for adjusting the tension of the fabric during production.

[0034] Further, the system comprises a tension control unit placed on a fabric spreader of the circular knitting machine. The tension control unit may be equipped with mechanisms like actuators, electrical springs, and clampers to vary tension at specific intervals, making subtle fabric defects, such as Lycra issues, more visible.

[0035] The system integrates cameras and optimized lighting unit for real-time defect identification and comprises a fabric processing unit. In certain embodiments, the system may comprise a tension sensor unit configured to measure or monitor fabric tension during the knitting process.

[0036] depicts / illustrates a system 100 for intentionally altering fabric tension and / or fabric geometry during operation in a circular knitting machine 102 in order to reveal fabric defects that are otherwise not visible under normal tension conditions, in accordance with an embodiment of the present disclosure.

[0037] In an embodiment, the at least one fabric defect may comprise Lycra defect.

[0038] The Lycra defect may comprise imperfections that arise specifically due to issues with Lycra (spandex or elastane) yarn during the knitting process. The Lycra is used to impart stretchability and elasticity to fabrics.

[0039] The Lycra defect may be at least one of Lycra stitches, Lycra floats, broken Lycra, and Lycra snags.

[0040] The system 100 comprises a circular knitting machine 102, a tension sensor unit 104, a tension control unit 106, at least one lighting unit 108, at least one camera 110, a communication network 112, and a fabric processing unit 114.

[0041] The circular knitting machine 102 produces knitted fabric and operates in a cylindrical fashion to create tube-shaped fabric that is flattened and wound onto a cylindrical rod.

[0042] In an embodiment, the circular knitting machine 102 may be at least one of an open width circular knitting machine or tubular circular knitting machine.

[0043] In an embodiment, the circular knitting machine 102 comprises at least one fixed structure, a knitted fabric and at least one rotating structure.

[0044] The fabric exits a knitting zone and travels along a fabric path that includes a tension alteration unit positioned downstream of the knitting elements and upstream of fabric winding or further processing. The tension alteration unit is configured to intentionally and temporarily alter fabric tension and / or fabric geometry during fabric formation.

[0045] The system tension alteration unit comprises at least one of: a fabric spreader, a brake shape alteration mechanism, and a clamping mechanism to dynamically adjust the tension of the fabric during the knitting process. A combination of one or more of these units may be used in the knitting machine.

[0046] The dynamically adjustable fabric spreader is configured to alter fabric width, flatness, or lateral tension.

[0047] The brake shape alteration or resistance mechanism is configured to temporarily resist fabric movement.

[0048] The clamping mechanism is configured to temporarily hold the fabric.

[0049] The tension alteration may be applied continuously, periodically, intermittently, or based on predefined timing, operator input, or automated control.

[0050] The alteration may increase tension, decrease tension, relax fabric, stretch fabric, or locally modify fabric geometry to expose latent defects.

[0051] The fabric spreader is described in detail below. The fabric spreader ensures smooth handling and consistent quality of the fabric as it exits the circular knitting machine. The fabric spreader evenly distributes and lays the fabric flat, preventing wrinkles, folds, or uneven tension, while maintaining the fabric's width and alignment for consistent dimensions. The fabric spreader also controls the edges of the fabric, preventing curling or distortion, and prepares the fabric for smooth winding onto rolls with uniform tension and alignment, which is crucial for downstream processes. The purpose of the fabric spreader extends to quality control by minimizing defects, enhancing efficiency in subsequent processes like inspection, cutting, or dyeing, reducing waste from distortions or uneven winding, and simplifying handling to improve operator efficiency.

[0052] The fabric spreader adjusts the fabric tension in longitudinal and transverse directions, and shape alteration of the spreader may release or redistribute lateral tension at specific zones of the fabric, thereby enhancing defect visibility.

[0053] In an embodiment, the fabric spreader may change its shape dynamically for a temporary duration.

[0054] In an embodiment, the fabric spreader may be installed at the top of the at least one rotating structure of the circular knitting machine 102.

[0055] The fabric spreader in the circular knitting machine is used for proper handling and alignment of the fabric. The fabric spreader comprises at least one of spreader bars, guide rollers, edge guides, support frames, guide belts, fabric sensors, brush mechanism, tension adjustment mechanism, and fabric exit guides. These parts work together to ensure the fabric is evenly spread, properly aligned, and tension-free, which is critical for high-quality knitted fabric production. This setup will be mounted to the rotating structure of the circular knitting machine.

[0056] The spreader bars may extend and maintain the fabric width as it exits the circular knitting machine. The spreader bars may be made of metal or coated materials to ensure a smooth surface that prevents snagging. The spreader bars may be adjustable to accommodate different fabric widths.

[0057] The guide rollers may assist in guiding the fabric through the fabric spreader.

[0058] The guide rollers help in maintaining consistent fabric tension while the fabric has been spread. The guide rollers are rubber-coated or polished metal for smooth fabric movement.

[0059] The edge guides may align and control the fabric edges to prevent curling or distortion. The edge guides may be fixed guides for standard fabric widths. These edge guides may be located on both sides of the fabric spreader.

[0060] The support frame provides structural stability for the fabric spreader. The support frame may be made of metal or aluminum to ensure durability and minimal vibration.

[0061] The guide belts convey the fabric through the spreader while maintaining its position. The guide belts are made of durable synthetic materials, often with anti-static properties.

[0062] The fabric sensors detect fabric alignment and tension to ensure proper spreading. The fabric sensors can provide signal adjustments to maintain fabric quality during production of the fabric.

[0063] The brush mechanism helps flatten the fabric and remove minor wrinkles as it moves through the spreader. The brush mechanism may be placed near the guide rollers or just after the spreader bars.

[0064] The tension adjustment mechanism allows operators to adjust the tension applied to the fabric, ensuring consistency and preventing over-stretching.

[0065] The fabric exit guides direct the fabric that is spread towards the winding system or further processing areas. The fabric exit guides often comprise smooth, polished surfaces to avoid damage to the fabric.

[0066] The brake shape alteration or resistance mechanism is described in detail below. The braking mechanism temporarily resists fabric movement while knitting continues, thereby relaxing newly formed fabric. The braking mechanism may comprise components comprising at least one of: mechanical, electrical, electromechanical, pneumatic, time-programmed, and manually actuated actuators.

[0067] The clamping mechanism is described in detail below. The clamping mechanism comprises at least one adjustable arm, clamps, and rollers, configured to temporarily hold or alter the fabric’s shape and tension in specific zones during the knitting process.

[0068] In an embodiment, the system 100 may comprise a circular knitting machine 102, a tension sensor unit 104 to monitor and measure tension in the fabric during the knitting process in form of fabric tension data, in real time.

[0069] In an embodiment, the tension sensor unit 104 is positioned near the fabric spreader.

[0070] The tension sensor unit 104 comprises at least one sensor, strategically positioned to capture the fabric tension data along multiple directions such as longitudinal and transverse directions of the fabric.

[0071] The tension sensor unit 104 sends the tension sensor data to the fabric processing unit 114.

[0072] The tension sensor unit 104 and the tension control unit 106 are optional, are used for monitoring / logging, and may not always be required for tension alteration.

[0073] The system 100 may comprise the tension control unit 106 to adjust the fabric tension / tension of the fabric which could be based on the tension sensor data received from the tension sensor unit 104.

[0074] In an embodiment, the tension control unit 106 is positioned on the rotating structure of knitting machine. The tension control unit employs clampers to momentarily halt the fabric's movement for a duration of 0.1 to 10 seconds, allowing the fabric to relax while on the knitting machine. Further, the shape of the fabric spreader can be adjusted to release lateral tension at specific spots. Once the fabric is relaxed, defects become more easily detectable.

[0075] The tension control unit 106 is provided with at least one actuator, electrical springs, and clampers.

[0076] In an embodiment, the actuator may be configured for adjusting the position and movement of the tension control unit to ensure precise tension control and uniform fabric alignment.

[0077] In an embodiment, the actuators may be electric, mechanical or pneumatic type.

[0078] In an embodiment, electrical springs for storing and releasing controlled amounts of tension dynamically to maintain consistent fabric stretch during operation.

[0079] In an embodiment, the clamper is configured to clamp or hold the fabric for a temporary duration to vary the fabric tension and inspect the at least one fabric defect.

[0080] The system 100 comprises the at least one lighting unit 108 to illuminate the fabric, during the altered fabric tension or geometry enhancing the visibility of at least one fabric defect.

[0081] The lighting unit may comprise visible light, directional illumination, or other suitable illumination techniques.

[0082] In an embodiment, the at least one lighting unit 108 may be placed around the at least one rotating structure of the circular knitting machine 102.

[0083] The at least one lighting unit 108 comprises at least one of an LED Lighting unit 108 Emitting Diode, a CMOS Complementary Metal-Oxide-Semiconductor sensor, a CCD Charge-Coupled Device sensor, Laser Diodes, Organic LEDs OLEDs, and photodiode.

[0084] The system 100 comprises the at least one camera 110 to capture at least one image of the fabric in order detect the at least one fabric defect in the real time, thereby providing captured data. The at least one camera 110 sends the captured data to the fabric processing unit 114.

[0085] At least one camera or imaging device is positioned to capture images of the fabric while the fabric is in the altered tension or geometry state, enabling detection of defects that are not visible under normal tension.

[0086] The system 100 may comprise the communication network 112 to facilitate data exchange between the tension sensor unit 104, the tension control unit 106, the at least one camera 110, and the fabric processing unit 114.

[0087] The communication network 112 may comprise wired and wireless communication, comprising but not limited to, GPS, GSM, LAN, Wi-fi compatibility, Bluetooth low energy as well as NFC. The wireless communication may further comprise one or more of Bluetooth registered trademark, ZigBee registered trademark, a short-range wireless communication such as UWB, a medium-range wireless communication such as Wi-Fi registered trademark or a long-range wireless communication such as 3G / 4G or WiMAX registered trademark, according to the usage environment.

[0088] The system 100 may comprise the fabric processing unit 114 to automate the fabric stopper mechanism 104 and the at least one camera 110.

[0089] Further, the fabric processing unit 114 triggers an alert through a user interface to a user, to stop the circular knitting machine 102 upon detection of the at least one fabric defect. The processing unit 114 may provide visual alerts, logs, or actionable insights but is not required for the core operation of the invention.

[0090] In an embodiment, the fabric processing unit 114 may be placed in proximity to the circular knitting machine 102 or placed on the fixed structure of the circular knitting machine 102.

[0091] In certain embodiments, the fabric processing unit 114, when present, may be operatively connected to the at least one camera 110, and at least one lighting unit 108 to adjust the fabric tension based on the tension sensor data.

[0092] The fabric processing unit 114 may also process collected data, classify detected at least one fabric defect, and provide actionable insights for fabric quality assurance.

[0093] depicts / illustrates a block diagram of a fabric processing unit 114, in accordance with an embodiment of the present disclosure.

[0094] The fabric processing unit 114 comprises at least one of a data acquisition module 202, a signal processing module 204, an artificial intelligence (AI) processing module 206, a tension control module 208, a defect detection module 210, a user interface module 212, a communication module 214 and a memory module 216.

[0095] The data acquisition module 202 is configured to collect the tension sensor data and the captured data from the tension sensor unit 104 and the at least one camera 110. Herein, the tension sensor data and the captured data are also referred to as real-time data. The data acquisition module 202 collects the real-time data on the fabric properties such as surface texture, tension, and material characteristics.

[0096] The signal processing module 204 is configured to preprocess the collected real-time data from the data acquisition module 202. The signal processing module 204 is configured for filtering noise, normalizing signals, and converting analog inputs to digital formats for further analysis.

[0097] Further, the processed data from signal processing module 204 is transmitted to the artificial intelligence (AI) processing module 206.

[0098] The artificial intelligence (AI) processing module 206 is configured to classify and predict at least one fabric defect from the processed data using machine learning models trained on large datasets of the at least one fabric defect.

[0099] The artificial intelligence (AI) processing module 206 comprises deep learning frameworks, neural networks, and decision-making algorithms that adapt to different fabric types and production conditions.

[0100] The tension control module 208 is configured to adjust the fabric tension during production based on the processed data.

[0101] The tension control module 208 comprises at least one tension adjusting mechanism to adjust the tension in the fabric using the tension control unit 106.

[0102] The defect detection module 210 is configured to inspect the at least one fabric defect based on the processed data.

[0103] The defect detection module 210 flags at least one fabric defect that exceeds predefined thresholds and triggers corrective actions, such as stopping the machine or alerting the operator through the user interface. Once the at least one fabric defect is detected, the defect detection module 210 generates feedback. The feedback may comprise stopping the circular knitting machine, adjusting fabric tension dynamically, or alerting the operator through the user interface of the circular knitting machine.

[0104] The defect detection module 210 comprises algorithms for threshold-based defect identification, and a defect classification.

[0105] The threshold-based defect identification algorithms analyze the data processed by the AI processing module 206 to determine whether the fabric exhibits any anomalies that exceed predefined tolerance limits / thresholds. These algorithms compare the data processed by the AI processing module 206 against these thresholds and flag any discrepancies, such as fabric irregularities, texture inconsistencies, or color variations. Additionally, the defect classification algorithm uses machine learning techniques to categorize the types of at least one fabric defect, whether they are small Lycra defects, tension issues, or surface imperfections. The user interface module 212 is configured to provide real-time feedback received from the defect detection module 210 on fabric quality and the at least one fabric defect to the operator through a user interface or a touchscreen display of the circular knitting machine.

[0106] Further, the user interface module 212 is equipped with the interface for triggering machine responses when the at least one fabric defect is detected. This interface communicates with the circular knitting machine to take corrective actions, such as stopping the machine, adjusting tension, or alerting the operator.

[0107] The user interface module 212 comprises the touchscreen display, a control panel, and software dashboards for visualizing defect data and machine performance metrics.

[0108] The communication module 214 is configured to enable seamless data transfer between the fabric processing unit 114 and external systems, such as enterprise resource planning ERP software, quality control databases, and remote monitoring tools.

[0109] The communication module 214 comprises wireless connectivity e.g., Wi-Fi, Bluetooth, Ethernet interfaces, and standardized communication protocols for integrating with external systems.

[0110] The memory module 216 is configured to store historical data, machine learning models, system configurations, and production logs.

[0111] The memory module 216 comprises non-volatile storage devices, such as solid-state drives SSDs or flash memory, and comprises a database management for efficient data organization and retrieval.

[0112] Figures 3a depicts / illustrates exemplary embodiments of the tension control unit in the open-width circular knitting machine, in accordance with an embodiment of the present disclosure;

[0113] In, the open-width circular knitting machine incorporates a brake shape alteration mechanism comprising the fabric 302 revolving downward, a top cylinder 304, at least one fixed structure 306, at least one rotating structure 308, a tension control unit 106, a brake pad moving forward 312, an actuator 314, a mounting clamp 316. This configuration is suitable for addressing defects requiring one-sided tension adjustment.

[0114] The fabric 302 moves downward as it is produced, while the top cylinder 304 houses knitting components that ensure consistent and precise fabric formation. The at least one fixed structure 306 provides stability, and the at least one rotating structure 308 interacts with the fabric to maintain even tension. The tension control unit 106 alters or modifies fabric tension to prevent distortions, while the brake pad 312, driven by the actuator 314, moves forward to apply localized pressure for targeted adjustments. The mounting clamp 316 secures the components on one side of the fabric spreader, ensuring proper alignment and functionality.

[0115] Figures 3b depicts / illustrates exemplary embodiments of the tension control unit in the tubular circular knitting machine, in accordance with an embodiment of the present disclosure;

[0116] In the, the tubular circular knitting machine comprises the at least one fixed structure 306, the at least one rotating structure 308, the brake pad moving forward 312, the tension control unit 106, the actuator 314, the mounting clamp 316.

[0117] The at least one fixed structure 306 provides stability, while the at least one rotating structure 308 facilitates controlled movement during the knitting process. The tension control unit 106, supported by the mounting clamp 316, ensures uniform tension across the fabric width, preventing defects caused by uneven tension. The brake pad 312 moving forward applies adjustable resistance, managed by the actuator 314, which dynamically adjusts tension based on real-time requirements.

[0118] Figures 3c and 3d depict / illustrate exemplary embodiments of the tension control unit in the tubular circular knitting machine, in accordance with an embodiment of the present disclosure.

[0119] In the, the tubular circular knitting machine comprises the fabric 302 revolving downward, the top cylinder 304, the at least one fixed structure 306, and the at least one rotating structure 308 to implement the tension control unit 106 shape alteration. The fabric spreader shape is not altered and is kept normal.

[0120] In the, the tubular circular knitting machine incorporates the fabric 302 revolving downward and a tension control unit 106 positioned exclusively on the fabric spreader with shape altered. The shape of the fabric spreader is adjusted to release lateral tension at specific spots. Once the fabric is relaxed, defects are more easily detectable.

[0121] This targeted tensioning is designed to highlight the at least one fabric defect that are otherwise hidden under balanced tension, particularly along longer sections of the fabric.

[0122] Figures 3e and 3f depict / illustrate exemplary embodiments of the tension control unit in the tubular circular knitting machine, in accordance with an embodiment of the present disclosure;

[0123] In the figures 3e and 3f, the tubular circular knitting machine comprises the fabric spreader along with the tension control unit 106 mounted on it.

[0124] In the, the normal fabric spreader is depicted without any shape alternation or tension alternation using the tension control unit 106 mounted on it.

[0125] In the, the fabric spreader shape for the tension alternation using the tension control unit 106. The shape of the fabric spreader is adjusted to release lateral tension at specific spots. Once the fabric is relaxed, defects are more easily detectable.

[0126] illustrates a method 400 for fabric quality control in a circular knitting machine, in accordance with an embodiment of the present disclosure.

[0127] The method begins with producing knitted fabric using a circular knitting machine, as depicted at step 402. Subsequently, the method 400 discloses intentionally altering fabric tension and / or fabric geometry during fabric formation, as depicted at step 404. Additionally, the method 400 discloses illuminating the fabric by using at least one lighting unit 108 integrated to enhance the visibility of at least one fabric defect, as depicted at step 406. Furthermore, the method 400 capturing images of the fabric during the altered state, as depicted at step 408. Furthermore, the method 400 discloses detecting or classifying fabric defects revealed by the altered state, as depicted at step 410. Furthermore, the method 400 discloses Optionally taking corrective action or generating alerts, as depicted at step 412.

[0128] The advantages of the current invention include real-time detection of defects during the knitting process, reducing the need for post-production inspection, detection of defects that are otherwise invisible under uniform tension, early identification of Lycra and elastic yarn defects, reduced fabric wastage, improved productivity, minimal machine disruption, compatibility with existing machines and flexibility to operate with or without sensors, AI, or automation

[0129] An additional advantage is that dynamic tension variation mechanism helps reveal defects that are otherwise invisible under uniform tension conditions, such as subtle Lycra defects

[0130] An additional advantage is that the system does not require multiple cameras or complex sensing systems or extensive lighting uniting setups, making it more cost-effective.

[0131] An additional advantage is that the fabric spreader modification integrates seamlessly into existing circular knitting machines, without significantly altering the machine’s operation or maintenance procedures.

[0132] An additional advantage is that tension control mechanism can be adjusted based on fabric type and order requirements, offering flexibility and customization for different production needs.

[0133] An additional advantage is that the system reduces the frequency of machine stoppages for manual inspection, improving overall machine productivity and efficiency.

[0134] An additional advantage is that the combination of the dynamic tension control unit and the lighting unit improves the visibility of defects both for human inspectors and automated detection systems, leading to higher accuracy in defect identification.

[0135] An additional advantage is that the system can detect a wide range of defects, including material irregularities, color variations, and structural issues, enhancing the quality control process.

[0136] An additional advantage is that the use of clampers and actuators minimizes the impact on fabric handling, ensuring that the fabric remains undamaged during inspection.

[0137] Applications of the current invention include textile manufacturing, knitting mills, elastic fabric manufacturing, quality control processes, sportswear production, medical fabric fabrication, Lycra and stretch fabric production, and automated defect inspection systems.

[0138] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and / or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the scope of the embodiments as described here.]

Claims

A system for fabric quality control in a circular knitting machine, comprising:a circular knitting machine (102) to produce knitted fabric;a tension alteration unit configured to temporarily alter at least one of: fabric tension, and fabric geometry during fabric production, to present the fabric in at least two different tension states;at least one lighting unit (108) to illuminate the fabric during the altered fabric tension or geometry;at least one camera (110) to capture and communicate one or more images of the fabric in case the fabric is in the altered fabric tension or geometry; anda fabric processing unit (114) to process at least one of: the images to detect and classify at least one fabric defect that becomes visible due to the altered fabric tension or geometry, for fabric quality control.The fabric quality control system as claimed in claim 1, wherein the tension alteration unit comprises at least one of:a dynamically adjustable fabric spreader configured to alter fabric width, flatness, or tension;a braking mechanism configured to temporarily resist fabric movement; anda clamping mechanism comprising clampers to clamp or hold the fabric for a temporary duration to vary fabric tension and inspect the at least one fabric defectThe fabric quality control system as claimed in claim 2, wherein the fabric spreader changes its shape dynamically,wherein the fabric spreader is installed at a top of at least one rotating structure of the circular knitting machine (102), wherein the fabric spreader is used to evenly distribute and lay the fabric flat to adjust fabric tension in longitudinal and transverse directions, preventing wrinkles, folds, or uneven tension, for maintaining the fabric's width and alignment for consistent dimensions;wherein the fabric spreader comprises at least one adjustable arm, clamps, and rollers, configured to temporarily alter the fabric’s shape and tension in specific zones during the knitting process, wherein the fabric spreader comprises at least one of:spreader bars made of metal or coated materials to ensure a smooth surface that prevents snagging, wherein the spreader bars are adjustable to accommodate different fabric widths;guide rollers comprising rubber-coated or polished metal for smooth fabric movement, wherein the spreader bars extend and maintain the fabric width as it exits the circular knitting machine;edge guides located on both sides of the fabric spreader to align and control the fabric edges to prevent curling or distortion,at least one support frame comprising metal or aluminum to ensure durability and minimal vibration;guide belts made of durable synthetic materials with anti-static properties, to convey the fabric through the spreader while maintaining its position;fabric sensors to detect fabric alignment and tension to ensure proper spreading of the fabric;a brush mechanism placed near the guide rollers or just after the spreader bars to flatten the fabric and remove minor wrinkles;a tension adjustment mechanism enabling operators to adjust the tension applied to the fabric, ensuring consistency and preventing over-stretching; andfabric exit guides comprising smooth, polished surfaces to avoid damage to the fabric to direct the fabric that is spread towards the winding system or further processing areas.The fabric quality control system as claimed in claim 2, wherein the brake shape alteration mechanism comprises:a top cylinder (304) to house knitting components;at least one fixed structure (306) attached to the top cylinder (304), to provide stability;at least one rotating structure (308) to interact with the fabric and maintain even tension and controlled movement during the knitting process;a brake pad (312) moving forward to apply adjustable resistance;an actuator (314) to dynamically adjust tension based on real-time requirements; anda mounting clamp (316) to secure components on one side of the fabric spreader.The fabric quality control system as claimed in claim 1, comprising:a tension sensor unit (104) to monitor tension in the fabric during knitting process and measure and communicate at least one fabric tension data to the tension control unit (106);at least one sensor comprised in the tension sensor unit (104), wherein the sensor is strategically positioned to capture the fabric tension data along multiple directions such as longitudinal and transverse directions;a tension control unit (106) communicatively coupled to at least one of: the circular knitting machine (102) and the tension sensor unit (104) to adjust the fabric tension / tension of the fabric;the lighting unit (108) placed around at least one rotating structure of the circular knitting machine (102), wherein the lighting unit (108) comprises at least one of: an LED Lighting unit (108) Emitting Diode, a CMOS Complementary Metal-Oxide-Semiconductor sensor, a CCD Charge-Coupled Device sensor, Laser Diodes, Organic LEDs OLEDs, and photodiode; anda communication network (112) to facilitate data exchange between the tension sensor unit (104), the tension control unit (106), the at least one camera (110), and the fabric processing unit (114);The fabric quality control system as claimed in claim 1, the tension control unit (106) comprises at least one of:at least one actuator for adjusting the position and movement of the tension control unit to ensure tension control and uniform fabric alignment, wherein the actuators are electric, mechanical or pneumatic actuators;electrical springs for storing and releasing controlled amounts of tension dynamically to maintain consistent fabric stretch during operation.The fabric quality control system as claimed in claim 1, wherein the fabric processing unit (114) comprises at least one of:a data acquisition module (202) to collect the tension sensor data and the captured data from the tension sensor unit (104) and the at least one camera (110);a signal processing module (204) to preprocess the collected real-time data from the data acquisition module (202) by at least one of filtering noise, normalizing signals, and converting analog inputs to digital formats;an artificial intelligence (AI) processing module (206) to classify and predict at least one fabric defect from the processed data using machine learning models trained on large datasets of the at least one fabric defect, comprising deep learning frameworks, neural networks, and decision-making algorithms that adapt to different fabric types and production conditions;a tension control module (208) comprising at least one tension adjusting mechanism to adjust the tension in the fabric using the tension control unit (106);a defect detection module (210) configured to:flag at least one fabric defect that exceeds predefined thresholds by using threshold-based defect identification algorithms to compare data processed by the AI processing module (206) against these thresholds and flag any discrepancies, such as fabric irregularities, texture inconsistencies, or color variations;trigger corrective actions; andgenerate feedback in case the fabric defect is detected by using a defect classification algorithm using machine learning techniques to categorize the types of at least one fabric defect, wherein the feedback comprises stopping the circular knitting machine, adjusting fabric tension dynamically, or alerting an operator through a user interface of the circular knitting machine;a user interface module 212) to provide near real-time feedback on fabric quality and the at least one fabric defect to the operator through a user interface or a touchscreen display of the circular knitting machine;a communication module 214) to enable seamless data transfer between the fabric processing unit (114) and external systems comprising enterprise resource planning ERP software, quality control databases, and remote monitoring tools; anda memory module 216 to store historical data, machine learning models, system configurations, and production logs.A method for controlling fabric quality in a circular knitting machine, comprising:producing knitted fabric, by a circular knitting machine (102);temporarily altering at least one of: fabric tension, and fabric geometry during fabric production, to present the fabric in at least two different tension states;illuminating the fabric during the altered fabric tension or geometry;capturing and communicating one or more images of the fabric in case the fabric is in the altered fabric tension or geometry;processing at least one of: the images and the fabric tension data;detecting and classifying at least one fabric defect that becomes visible due to the altered fabric tension or geometry, for fabric quality control.The method for controlling fabric quality as claimed in claim 8, comprising at least one of:using a dynamically adjustable fabric spreader configured to alter fabric width, flatness, or tension;using a braking mechanism configured to temporarily resist fabric movement; andusing a clamping mechanism comprising clampers to clamp or hold the fabric for a temporary duration to vary fabric tension and inspect the at least one fabric defect.The method for controlling fabric quality as claimed in claim 9, comprising:changing the shape of the fabric spreader dynamically, wherein the fabric spreader comprises at least one adjustable arm, clamps, and rollers, configured to temporarily alter the fabric’s shape and tension in specific zones during the knitting process;attaching spreader bars made of metal or coated materials to ensure a smooth surface that prevents snagging, wherein the spreader bars are adjustable to accommodate different fabric widths;attaching guide rollers comprising rubber-coated or polished metal for smooth fabric movement, wherein the spreader bars may extend and maintain the fabric width as it exits the circular knitting machine;attaching edge guides on both sides of the fabric spreader to align and control the fabric edges to prevent curling or distortion,attaching at least one support frame comprising metal or aluminum to ensure durability and minimal vibration;attaching guide belts made of durable synthetic materials with anti-static properties, to convey the fabric through the spreader while maintaining its position;attaching fabric sensors to detect fabric alignment and tension to ensure proper spreading of the fabric;attaching a brush mechanism near the guide rollers or just after the spreader bars to flatten the fabric and remove minor wrinkles;providing a tension adjustment mechanism to enable operators to adjust the tension applied to the fabric, ensuring consistency and preventing over-stretching; andattaching fabric exit guides comprising smooth, polished surfaces to avoid damage to the fabric to direct the fabric that is spread towards the winding system or further processing areas.The method for controlling fabric quality as claimed in claim 9, comprising using the shape alteration mechanism by:housing knitting components in a top cylinder (304);attaching at least one fixed structure (306) to the top cylinder (304), to provide stability;providing at least one rotating structure (308) to interact with the fabric and maintain even tension and controlled movement during the knitting process;using a brake pad (312) moving forward to apply adjustable resistance;using an actuator (314) to dynamically adjust tension based on real-time requirements; andusing a mounting clamp (316) to secure components on one side of the fabric spreader.The method for controlling fabric quality as claimed in claim 8, comprising:measuring and communicating fabric tension data using a tension sensor unit (104); positioning at least one sensor in the tension sensor unit (104) to capture the fabric tension data along multiple directions such as longitudinal and transverse directions;using the fabric tension / tension of the fabric based on the tension sensor data, by a tension control unit (106);maintaining the fabric's width and alignment for consistent dimensions;placing the lighting unit (108) around at least one rotating structure of the circular knitting machine (102), wherein the lighting unit (108) comprises at least one of an LED Lighting unit (108) Emitting Diode, a CMOS Complementary Metal-Oxide-Semiconductor sensor, a CCD Charge-Coupled Device sensor, Laser Diodes, Organic LEDs OLEDs, and photodiode; andfacilitating data exchange between the tension sensor unit (104), the tension control unit (106), the at least one camera (110), and the fabric processing unit (114);The method for controlling fabric quality as claimed in claim 8, comprising using the tension control unit (106) by:using at least one actuator for adjusting position and movement of the tension control unit to ensure tension control and uniform fabric alignment, wherein the actuators are electric, mechanical or pneumatic actuators;attaching electrical springs for storing and releasing controlled amounts of tension dynamically to maintain consistent fabric stretch during operation; andattaching clampers to clamp or hold the fabric for a temporary duration to vary fabric tension and inspect the at least one fabric defect.The method for controlling fabric quality as claimed in claim 7, comprising using the fabric processing unit (114) by:collecting the tension sensor data and the captured data from the tension sensor unit (104) and the at least one camera (110);preprocessing the collected real-time data from the data acquisition module (202) by using at least one of filtering noise, normalizing signals, and converting analog inputs to digital formats;classifying and predicting at least one fabric defect from the processed data using machine learning models trained on large datasets of the at least one fabric defect, comprising deep learning frameworks, neural networks, and decision-making algorithms that adapt to different fabric types and production conditions;using at least one tension adjusting mechanism to adjust the tension in the fabric using the tension control unit (106);flagging at least one fabric defect that exceeds predefined thresholds by using threshold-based defect identification algorithms to compare data processed by the AI processing module (206) against these thresholds and flag any discrepancies, such as fabric irregularities, texture inconsistencies, or color variations;triggering corrective actions; andgenerating feedback in case the fabric defect is detected by using a defect classification algorithm using machine learning techniques to categorize the types of at least one fabric defect, wherein the feedback comprises stopping the circular knitting machine, adjusting fabric tension dynamically, or alerting an operator through a user interface of the circular knitting machine;providing near real-time feedback on fabric quality and the at least one fabricdefect to the operator through a user interface or a touchscreen display of the circular knitting machine;enabling seamless data transfer between the fabric processing unit (114) and external systems comprising enterprise resource planning ERP software, quality control databases, and remote monitoring tools; andstoring historical data, machine learning models, system configurations, and production logs.

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