Question 14 (Textile Engineering & Fibre Science)
Nep setting on evenness tester is related to the percent mass deviation based on yarn length of
| (A) | 10 mm |
| (B) | 8 mm |
| (C) | 4 mm |
| (D) | 1 mm |
[Show Answer]
Option D is correct
Frequently Asked Questions | FAQs
What is the working principle of evenness tester?
An evenness tester, also known as a fabric or yarn evenness tester, is an instrument used in the textile industry to measure the evenness or uniformity of a fabric or yarn. The working principle of an evenness tester involves the following steps:
Sample Preparation: A representative sample of the fabric or yarn is taken and prepared for testing. For fabrics, a small section is cut and properly aligned, ensuring it is free from wrinkles, folds, or distortions. For yarns, a specific length is selected, usually wound on a package or a bobbin, and prepared in a way that minimizes any variations.
Tensioning: The fabric or yarn sample is subjected to controlled tensioning to simulate the conditions under which it will be used or processed. This tensioning helps in minimizing any inherent variations in the sample and provides a standardized basis for measurement.
Sensor Detection: The sample is then passed through a sensing area or detection zone, which consists of various types of sensors depending on the evenness tester model. These sensors can be optical, capacitive, or magnetic, among others, and are designed to detect and measure various characteristics of the sample.
Measurement: As the sample passes through the detection zone, the sensors collect data on parameters such as yarn/fabric thickness, diameter, density, hairiness, or variations in color. The sensors generate electrical signals or readings that are processed by the instrument.
Data Analysis: The collected data is analyzed by the evenness tester, which calculates various statistical measures such as mean, standard deviation, coefficient of variation, or specific indices like U%, IPI (Imperfection Index), or CVm% (Coefficient of Variation of Mass). These measures quantify the evenness or uniformity of the sample, indicating the level of variation present.
Results and Evaluation: The instrument provides numerical results or graphical representations based on the measured data. These results help textile professionals to evaluate the quality of the fabric or yarn and make informed decisions regarding manufacturing processes, product development, or quality control.
It’s important to note that evenness testers can vary in terms of their design, capabilities, and specific measurements provided. Different types of sensors and algorithms may be used, depending on the manufacturer and the intended application (fabric or yarn). The principle remains the same: measuring and quantifying the variations in the sample to assess its evenness.