With the development of science and technology, various high-tech techniques have been injected into the textile industry, injecting new vitality into the textile industry. Despite the development of the international textile industry, new textile technology, new textile machinery and equipment have been emerging, and the textile industry has undergone rapid changes. Textile testing techniques and testing equipment are also rapidly developed.
1. The use of high-tech techniques in textile testing
1.1 The use of infrared spectroscopy in the identification of textile fibers
The infrared spectrometer, which was originally used for textile fiber identification, was made by applying the principle of light dispersion. The discrimination principle is that when the incident light passing through the object is dispersed by monochromators such as prisms, gratings, etc., the composite light is divided into monochromatic light, which is displayed on the three-dimensional slit in the order of wavelength, and the signal is received by the detector. Light signal, stop measuring the intensity of monochromatic light one by one, that is, lose the received spectrum of the sample. In the infrared spectrometer used in the past, because only a very narrow section of light wave falls on the detector at every moment of scanning, the sensitivity and detection rate are both limited. And Fourier changed the infrared spectrometer to use the Michelson interference instrument to make the spectral signal "multiplexed", and the interference signal was converted into a general spectral signal by the Fourier mathematical change, so that it can be used in The information of all frequencies in the unified time network spectrum can scan the entire spectrum nearly a thousand times in one minute, thus greatly improving the acuity and task effectiveness. Through the analysis of the infrared spectrum of a large number of textile fibers, it is possible to grasp their infrared spectrum characteristics, and to achieve a quantitative analysis of the proportion of blended fabrics.
1.2 The use of laser detection in textiles
Among the radiation sources adopted by the photoelectric detection installation, the laser has a special main position. The principle of laser light emission is completely different from general light sources, basically breaking through the various ranges of general light sources, and having excellent characteristics different from general light sources. Laser detection is a major aspect of laser utilization in the textile industry. It can be used to inspect fabrics, inspect fabric pilling, hairiness and its roughness, inspect fabric weft, measure yarn diameter, unevenness, yarn defects and fiber function, control printing and dyeing, and test dressing.
1.2.1 Laser cloth inspection
To find the nominal defect of the fabric by photoelectric method, it is important to base on the difference between the nominal reflection coefficient of the fabric at the defect site and the nominal reflection coefficient of the fabric without the defect. When the laser radiation is transferred from the non-defective part of the fabric to the defective part, the reflected light reflected from the fabric will show a change. Therefore, when there are more obvious defects in the sight of the photoelectric receiver, it will cause the photoelectric receiver to change the illuminance which is impossible. At this time, the image analyzer is used to stop the analysis, and then the computer can display the results. Laser cloth inspection not only improves the effectiveness of rest, but also improves the performance of detection.
1.2.2 Laser inspection fabric
The evaluation of pilling fabrics by laser detection method is based on the number of pillings, the height of the pellets and the total projected area of the pellets on the unit area to establish the pellet grading scale. The sample is compared with the pellets to evaluate the fabric pilling. Ball grade. The roughness of the fabric is evaluated by the laser sensor through the triangle measurement technique to measure the height of the fabric in different positions. In the past, the detection of pilling and roughness of fabrics was done by experts to stop objective evaluation or use a combat measuring instrument, and the supervisor’s evaluation results lacked reliability and divergence. The application of laser detection overcomes the above drawbacks and achieves rapid detection.
1.2.3 Laser inspection yarn
The beam reflected by the laser is projected onto the measured yarn after beam expansion. The measured yarn covers a part of the luminous flux, and the other parts are received by the photocell set up in the front and converted into photocurrent and photovoltage. The difference in yarn thickness, the difference in the luminous flux of the shade, the difference in the magnitude of the photovoltage and the photocurrent. In this way, the change in yarn thickness is converted into a small change in photocurrent and photovoltage. This photoelectric signal is a weak signal, which needs to be reduced and filtered to make it uneven Corresponding to imitate the voltage signal, and then the computer outputs the result with the clear potential of the figure or figure.
1.3 The use of image processing techniques in textiles
Computer image information processing techniques are now used in many aspects of the textile industry. On the one hand, it is used in textile testing techniques and textile instrument development. Image information processing techniques are used in a wide range of textile inspection techniques, including: fiber fineness measurement, yarn unevenness, hairiness, defects, cloth inspection, etc.
Therefore, a profound and systematic study of the use of image information processing technology in textile technology testing will enhance the upgrading of a large number of textile instruments; on the other hand, it is used in the fabric simulation CAD system, and the fabric simulation simulation technology is used to develop New product. The fabric simulation CAD system developed by the China Textile Science Research Institute is a software that uses simulation methods to develop fabric products. The fabric simulation CAD system currently on the market has reached the level of advancement in the world, and some aspects are ahead of the international level, such as the imitation of double-layered inner and outer layers, and the nominal imitation method of raised fabrics. In reality, the use of image information processing techniques in the textile industry still has great potential. For example, in the existing fabric simulation CAD system, basically, combined with textile inspection techniques, it can realize from the detection of yarns and objects to the simulation of fabrics, not only to evaluate the quality of the yarn, but also to provide a basis for leading production, and Can guess the surface quality of the fabric woven with this yarn.
2. Development status and trends of testing techniques and instruments
The development of conventional textile instruments in my country has been able to satisfy the textile industry’s request for functional testing of textile materials. A number of high-tech testing instruments have been launched on the market, such as: capacitive evenness tester, capacitive fiber length tester, fully active single yarn strength仪等。 Instrument and so on. Some instruments may have been on the verge of international progress, providing a greater choice for technical testing of textiles in my country. The development and convergence of testing instruments are manifested in the following aspects: testing instruments are developed towards multi-function and automation; instrument control and data processing have been computerized; the use of photoelectric conversion techniques is becoming more and more common; testing is still gradually realized by manual operation of instruments化 etc.
Nowadays, domestic and foreign textile testing instruments have different levels of improvement and progress in the testing functions and the utilization of high-tech techniques, which are mainly expressed in the following aspects: test types are becoming more and more common; testing techniques pay special attention to situational imitation and accuracy; craftsmanship Parameter measurement is more trending in timely detection and on-machine detection; computer-controlled digital processing is more and more widespread; detection and operation are becoming more intelligent, automated, and low-skilled. We can really feel the serious changes brought about by the improvement of ancient technology, the spread of electronic information technology, and the suspension of mechatronics to textile inspection technology.
2.1 Automated and computerized testing efficiency
It has been proved that the use of computer and electrical measurement techniques to reform traditional outdated detection methods has obvious advantages in simplifying instrument structure, improving detection accuracy, task stability and reliability. Microcomputers and new sensors used to be the main components of textile testing equipment, and they should be slowed down and popularized. Under the control of a microcomputer, the testing instrument has realized the automatic process of sampling, cleaning, testing, reading data, statistical calculation, information storage, and printing results. The method prevents the deviation caused by manual manipulation and objective evaluation, shortens the test time and makes the manipulation simpler. Because the active control function of the microcomputer replaces the functions of many machine parts, the size of the instrument is reduced. The stronger the microcomputer is, the smaller the volume, and it appears lighter and more compact. Microcomputers have the advantage of high-speed, large-capacity data processing, which not only improves the detection rate, but also stores all relevant data for analysis and cleaning, making the detection more reliable.
2.2 Timely inspection and on-machine inspection
Basically, in traditional static testing, many instrument manufacturers have created static testing methods that are close to actual production and utilization, so as to obtain more realistic indicators of yarn production and utilization conditions, making the testing results closer to the actual value, making the yarn The manufacturers and users of the products are more effective in adjusting the production process and guessing the durability of the product. On-machine inspection can detect yarn quality one-sidedly, which is more one-sided than static data extraction in the laboratory. It is also possible to increase destructive tests and increase capital squandering, which is even more important for manufacturers with expensive materials.
2.3 Test techniques pay attention to the situation, imitate and guess
Fully use the image processing function of the computer, the new textile inspection instrument can output and store indecent graphic information, directly show the surface quality and structure function of the yarn, and can also imitate and guess the surface effect of the fabric, which saves experimental sample weaving Process, and make accurate and indecent judgments on the consequences of the use of yarn in the *products, so that product planning and process optimization have a straightforward shortcut. The automation of manipulation, the digitization and imaging of test results, and the random and active processing of test data have gradually replaced the traditional detection methods of hand and visual inspection, which constitute the glamorous characteristics of ancient textile detection techniques.
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