Textile Testing Terminologies
Textile testing refers to the process of evaluating the physical, mechanical, and chemical properties of fibers, yarns, fabrics, and finished garments using standard test methods. Before going for the testing part of the process, everyone must be aware of some standard terminologies related to textile testing. This article defines key terms and definitions used in textile testing, providing clarity for professionals, students, and enthusiasts in the field. Some of these are described here:
Quality:
When a person hears the word ‘quality,’ he instantly thinks of the possession of superior behavior and characteristics by any material. ISO defines this word slight differently. It says, “Ensemble of properties and characteristics of a product or a service which confer on it the capability to satisfy expressed or implicit requirements.” For example, a customer has a requirement of yarn of strength 10 cN/ tex, now if the yarn manufacturer produces the yarn of 20 cN/ tex expecting the customer to be happy, this will not be so. The manufacturer is not actually producing the quality. Quality does not mean that one must produce the best quality. It is the ability of the product or service to meet the requirement. The customer is satisfied with the strength of 10 cN/ tex, then there is no point in producing stronger yarn for the same price.
Testing:
This is defined as, ‘A means of determining the capability of an item to meet the specified requirements by subjecting the item to a set of physical, chemical, environmental, or operating actions and conditions.’ For example, if it is needed to know whether a yarn possess 10 cN/ tex strength or not, then some physical actions are applied to the yarn until it breaks. This action gives us an idea whether the yarn possesses the required strength or not. Similarly, if it is needed to know the blend percentage in a blended yarn, then some chemical actions, such as dissolution of components, is adopted. If someone wants to test the change in color under sunlight, then the material is exposed to that particular environmental condition, for example, sunlight. So basically, testing is done to determine whether that material is actually satisfying the required characteristics or not.
Inspection:
Unlike testing, the inspection has a wider remit and the testing is a part of the inspection process. It can be defined as, ‘The activities such as measuring, examining, and testing one or more characteristics of a product or service, and comparing these with specified requirements to determine conformity.’ For example, if it is needed to compare two batches of yarns, many aspects will be considered, for example, the quality of the bobbin, the strength of the yarns, the evenness of the yarns, the cleanliness of the yarns, the size of the yarn package, damages to the yarn packages, and so forth. So, it can be said that inspection is the checking of one or more characteristics of the product at one go to compare it with specified requirements to determine its conformity for a particular end use. Another example of inspection might be the end breakage study in the ring frame. This is not testing, but inspection. It can be done by counting the number of end breakages per hour in a particular ring frame and it can be compared with another ring frame or with the standard. The advantage of inspection is that it is an easy and quick method to know overall characteristics.
Quality control (QC):
Quality control is a very commonly used term in industry. It is actually the function of inspection and testing. It can be defined as, ‘The operational technique and activities used to fulfill the requirement of quality.’ It can be understood with the previous example. Assuming it is required to develop a yarn of 10 cN/ tex strength. This is the required quality of the yarn. To achieve this quality, one has to test the material, inspect it at every stage and take the required action to achieve the target strength. The total activities are aimed at ensuring that the yarn is of the specified strength and this is called quality control. One must be aware of what amount of waste and what trash percentage is needed, what fiber characteristics are required, what type of machine performance is expected, and the like. All these things are the components of inspection and testing of different aspects to achieve the required quality.
Statistical quality control (SQC):
As the name defines itself, it is essentially the same as quality control but with one difference, namely, quality control using statistical tools. For example, if someone wants to know the variability of the material and the significance of the difference in the quality between the materials, some statistical tools and terminologies are required, such as mean, standard deviation, coefficient of variation, and so forth. Some statistical tests, such as the t- test, F- tests, and the like, can be performed to check the significance of the difference in the quality.
Quality assurance (QA):
Quality assurance does not talk about the material only. It talks about the total process, namely, human resources, time management, motion study, and so forth. in addition to the material characteristics. It can be said that it totally a system designed to simply assure the quality. It can be defined as, “All those planned or systematic actions necessary to provide adequate confidence that a product or service will satisfy given requirements for quality.” The industry should have sufficient confidence that whatever they are producing will lead them to a particular quality. Considering the same example, say there is a need for a yarn having strength 10 cN/ tex. To have confidence that the resultant product will meet the requirement, the industry needs to have systematic plan. By strictly following this planned activity, industry will be able to achieve the desired quality with consistency. Quality assurance also depends upon the past experience of the industry. For example, control of vendors for the supply of raw materials. Buying random lots of the raw material from the open market from different vendors does not provide confidence in the quality. Based on industry’s previous experience, they have to identify few vendors who have already supplied a consistent quality of raw material. Buying from the trusted vendors raises confidence and assurance about the quality.
The next important aspect of quality assurance is “proper settings of the machines.” To have proper settings of the machines, a proper maintenance schedule must be in place. So ISO 9000 or different types of quality assurance standards are there which guide the machine settings or speed for any specific material. For example, to produce any specific yarn, machine settings such as roller pressure, machine gauge, roller hardness, and the like, are documented. The shop floor personnel: supervisor, mechanic, machine operators, and so forth, must follow these settings.
Particular environmental conditions have to be there to assure the quality of the material that is being developed. For example, in a spinning shed, particular environmental temperature and relative humidity must be there otherwise yarn breakage or roller lapping will be increased. Environmental need is different for different fibers, based on their characteristics and behavior.
Personnel training is another important aspect of quality assurance. Continuous training of personnel is necessary to achieve a consistent quality of product. Human resource development must be actively implemented. Otherwise, there is every possibility of having human related faults, lower productivity and inferior quality.
Proper time management is also a very important aspect. Quality assurance is not only about the product, but also about the service. It is mandatory to finish a required quality within a specified time. Suppose any buyer wants the material after one month of ordering it, and if the company is not able to supply that material within that specified time, then that means that non- conformity exists and that the company is not actually supplying a quality product.
Acceptable quality level (AQL):
Acceptable Quality Level (AQL) refers to the maximum percentage of defective items that can be considered acceptable in a particular batch during random sampling. It is a widely used statistical tool in the garment and textile industry to determine whether a production lot meets the required quality standards. AQL is crucial for balancing product quality with inspection efficiency, helping manufacturers meet buyer expectations without inspecting every single unit. It represents the maximum percentage of defective items that can be considered acceptable in a batch of products during inspection.
Quality management:
Quality management does not aim to assure ‘best quality’ by the more general definition, but rather to ‘ensure that an organization or product is consistent.’ For example, if a company is producing ‘D’ grade yarn, it will publish that this industry produces ‘D’ grade yarn only. Because for ‘D’ grade yarn quality, the company will have different products for a particular set of buyers. But it does not mean that company cannot go for higher quality. It can also try to achieve higher quality. Say that a company has achieved grade ‘B,’ then this quality should be consistent. So that the company will be known for that and will have customers who require that kind of quality. The more important aspect is that whatever the company claims, it must produce that quality with consistency. Quality management can be achieved by following four steps, namely: (i) Quality planning; (ii) Quality control; (iii) Quality assurance; and (iv) Quality improvement.
First of all, a company has to plan for the quality target, then quality control, quality assurance and lastly to achieve quality improvement. So, if today the company is producing say ‘B’ grade quality, then tomorrow it might have the target to achieve ‘A’ grade quality. But until then it must be satisfied with that. The company will have to claim that the quality is of ‘B’ grade, which is the best that they can offer at present.
Tolerance:
Tolerance refers to the permissible limit of variation in measurements or quality parameters during the manufacturing process. It ensures that products meet specified standards while accounting for the inherent variability in textile production. When testing textiles, certain properties (like GSM, shrinkage, color fastness, etc.) are measured against standard or buyer-specified values. Tolerance defines how much deviation is acceptable from these values.
Standard test atmosphere:
As previously discussed, testing atmosphere significantly affects the results because almost all the textile materials are hygroscopic in nature and different materials behave differently at different temperatures and humidity. To achieve the correct test results, one needs to maintain a standard atmosphere during testing and also the test specimen to be conditioned in that standard atmosphere for a certain specified duration before testing. So, one must know and maintain the standard relative humidity and temperature. According to the climate of the country, two different standards are followed.
In cold countries:
Relative humidity = 65 ± 2%
Temperature = 20 ± 2°C
In tropical or sub- tropical countries:
Relative humidity = 65 ± 2 %
Temperature = 27 ± 2°C
In any test results, one must mention the testing conditions. If someone tests a cotton yarn strength under 100% relative humidity and demands that the yarn is stronger, then it is misleading. Once the same cotton is tested under standard atmospheric condition, the strength value will be lower than the earlier reported value. Therefore, it is important to strictly follow standard test method and the standards followed during test must be mentioned along with the test results.
Conclusion
Textile testing is the systematic evaluation of fibers, yarns, fabrics, and finished products to ensure quality, performance, and compliance with industry standards. Understanding and applying these key terminologies in textile testing is essential for maintaining high product quality, meeting international standards, and ensuring customer satisfaction. From raw material testing to finished garment inspection, each test helps detect problems early and improve overall product performance. In the competitive textile industry, knowledge of testing terminology is a powerful tool for manufacturers, buyers, and quality control professionals alike.
References
[1] Das, A. (2024). Testing of textile and fibrous materials. CRC Press.
[2] Amutha, K. (2016). A practical guide to textile testing. CRC Press.
[3] Textile and Clothing Design Technology. (2017). In CRC Press eBooks. https://doi.org/10.1201/9781315156163
[4] Ahmad, S., Rasheed, A., Afzal, A., & Ahmad, F. (2017). Advanced textile testing techniques.
[5] Dolez, P., Vermeersch, O., & Izquierdo, V. (2017). Advanced characterization and testing of textiles. Woodhead Publishing.