What are Fabric Defects?
In the textile industry, fabric flaws refer to various defects that impact the appearance or functionality of the fabric. These flaws often originate at different stages of production, including the selection of raw materials, the weaving process, and post-processing techniques. Ideally, fabrics should exhibit uniform coloration, delicate texture, and a flawless pattern. However, poor quality raw materials or technical defects during manufacturing can lead to issues such as uneven coloration, rough fabric surfaces, and unclear patterns, all of which are considered flaws.
Discovering the underlying causes of fabric flaws
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Yarn Quality Issues: Include inherent defects like cotton neps and fly, commonly found during yarn production.
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Technical Issues in Processing: Such as sizing spots and tension mistakes during the preparatory stages.
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Improper Machine Settings: Leading to problems like loom marks or skipped threads.
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Operational Errors: Negligence by operators can lead to broken warp and weft threads or oil stains.
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Insufficient Post-Processing: Uneven dyeing or heat setting can result in an uneven fabric surface.
Grading Fabric Flaws: Assessing Impact from Minor to Severe
The severity of flaws is categorized based on their impact on the final use:
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Severe Flaws: Significantly affect the usability and appearance of the fabric, such as evident holes or spiderweb-like structures.
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Minor Flaws: After treatment, slight traces remain that may affect the appearance but not the functionality.
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Light Flaws: Post-processing leaves virtually no trace, not affecting the fabric's functionality or appearance.
Professional inspectors rely on their knowledge and skills to conduct effective defect inspections. The globally recognized 4-point system, which quantifies flaws based on size and their distribution across a specified fabric length, is instrumental in calculating deductions and ultimately determining fabric quality.
Implementing Strict Fabric Acceptance Standards and Procedures
To ensure that materials are supplied on time and in acceptable condition, fabric inspectors typically follow the specified processes to examine fabrics and fill out fabric inspection reports, while quality assurance specialists supervise fabric inspectors' work and review inspection reports.
Pre-inspection Preparation
To ensure fabric quality and meet delivery requirements, suppliers must follow a strict pre-acceptance preparation procedure: usually submit the bulk yardage and cylinder spread sheets for signature by the fabric ordering staff 7 days prior to acceptance, conduct a 100% quality inspection of the fabric with all defects clearly labeled, and complete the necessary fastness tests and submit the test reports themselves.
Ensure that each bolt of fabric is labeled at one end with the customer's order number, product name, color, cylinder number, bolt number, length, width, net weight, gross weight, and color-coded label. If the fabric does not meet these requirements, note in the Fabric Inspection Report which items are missing and contact the fabric counter to confirm possible errors.
During Inspection Preparation
During the inspection phase, a representative from the fabric ordering department collaborates closely with the fabric manufacturer to jointly inspect the materials. The acceptance procedure normally involves random sampling, with the goal of inspecting 10% of each cloth batch. If there are clearly visible flaws in more than 40% of any single roll, the next manufacturer has the right to reject the product. Also, the textile manufacturer usually pays for any costs that come up with re-inspection.
Analyzing the Three Mainstream Inspection Techniques
Traditional Inspection Machines
Traditional inspection machines are straightforward: fabric is placed on a manually operated machine and passed over a sloped board illuminated from behind to facilitate observation. The machine typically operates at 15-20 meters per minute, making it ideal for special materials or small-scale production. However, this method heavily relies on the experience and concentration of the operator, resulting in relatively low inspection efficiency, especially in environments with large fabric quantities or high staff turnover. Additionally, manual inspections depend heavily on the operator's judgment, leading to variability in flaw assessment that can affect the inspection's reliability and consistency.
Visual System Inspection Machines
Visual system inspection machines use high-resolution cameras for continuous fabric shooting, coupled with advanced artificial or automated software for precise flaw classification. In the industry, Automated Optical Inspection (AOI) and Artificial Intelligence (AI)-based inspection systems are two popular technologies. AOI systems can rapidly detect flaws in the same type of fabric, significantly reducing inspection time and training requirements. However, when faced with different types of fabric flaws, AOI systems rely on precise initial parameter settings. Conversely, AI-based inspection systems can learn and improve with increasing data volume, but they require a substantial amount of diverse flaw data to train the model, which can lead to higher initial time and labor costs.
Evaluation
Although there is no perfect fabric inspection machine on the market, each system has its unique advantages. In the long term, visual system inspection machines, with their ability to provide data connectivity and real-time data analysis, have the potential to significantly enhance operational efficiency and accelerate decision-making processes. For textile factories moving towards Industry 4.0, this can be a strategy to support sustained competitiveness. Of course, the choice of the right inspection machine should also consider individual production needs, technical readiness, and expected return on investment to ensure optimal quality control.
Conclusion
In the textile industry, detecting fabric faults is critical for assuring product quality and can have a substantial impact on reputation and costs. From traditional to advanced visual system inspection machines, each has its own set of advantages and is appropriate for a variety of production scenarios. Traditional inspection machines are suitable for small-scale production and special materials, relying on the experience fabric inspector to detect flaws. In contrast, visual system inspection machines, which include rule-based pattern and AI technologies, provide faster and more consistent inspection findings, making them ideal for large-scale and diversified small-quantity production scenarios.
For these requirements, OSHIMA, a manufacturer of inspection machine equipment, provides a complete variety of solutions, from classical to modern artificial intelligence technologies, assuring that we are your first choice for high-quality inspection equipment. OSHIMA provides professional equipment and expert help to optimize your fabric checking process. For more information, please contact us.
