Development Of Testing Instrument For Elongation And Recovery Of Textiles

< p > < < a href= > //www.sjfzxm.com/news/index_c.asp > > textile > /a > testing, there are many tests about the elongation and recovery performance of < a href= > //www.sjfzxm.com/news/index_c.asp > fabric > /a > or yarn. There are many factors that affect the elongation and refolding performance of textiles, which are divided into time, load and length. In practice, there are many defects such as heavy workload, low precision and unstable test data. This paper develops a tester with complete functions, versatility and simple operation, which can measure the elongation and recovery performance of all kinds of fabrics and yarns quickly and accurately. < /p >
< p > < strong > 1 the defects of the existing detection methods are < /strong > < /p >.
< p > existing detection methods can be mainly divided into two types, one is the old-fashioned suspension measurement, the heavy hammer is applied to load the sample, and the parallel ruler is used to measure the test results. The second is also the commonly used elastic material testing machine method. < /p >
< p > < strong > 1.1. Manual method is inflexible with low accuracy < /strong > < /p >.
< p > there are many disadvantages and shortcomings in the old hanging ruler measurement. For example, the weight of the hammer is easy to touch the surrounding obstacles, affect the accuracy of the load, and the accuracy and time accuracy of the specific measurement. This method has been applied to the actual inspection less and less. < /p >
< p > < strong > 1.2, there are defects in instrument test method < /strong > < /p >.
There is also a certain degree of disagreement in the strict scientific view of the existing strong machine test method commonly used in P. The tensile load exerted by the instrument is followed by the following way. That is to set a following range in advance. When the specimen relaxes, the force in the same length will be smaller. When the value exceeds the predetermined value, the instrument will continue to stretch down at a very low speed. When the load is reached, the instrument will stop drawing and enter the ready state. When the load changes again exceed the set value, the instrument will continue to stretch. It is not difficult to see that the rated load exerted by the instrument is actually a nonlinear change curve, which is contrary to the constant load required by the test. Although the tracking speed of the instrument is very small, for smaller specimens with smaller elongation, the smaller length changes will cause greater stress increase, which will often exceed the predetermined range of follow up, thus affecting the accuracy of the test. In the existing testing equipment, the minimum operating speed of the instrument varies greatly, which is one of the objective factors in the detection method. In the daily inspection, the inspector usually determines and modifies the following range and following speed because he is not familiar with the characteristics of the sample. This will greatly affect the detection efficiency and increase the risk of detection. < /p >
< p > < strong > 2 the design of yarn elongation and recovery tester of textiles < /strong > < /p >
< p > < strong > 2.1 the main body design is < /strong > < /p >.
< p > the textile < a href= "//www.sjfzxm.com/news/index_c.asp" > yarn > /a > elongation and reversibility tester, mainly in the aspects of measuring accuracy, constant load, simple structure, easy operation and so on, so as to improve the accuracy and efficiency of detection. < /p >
< p > choose double arm frame structure, make the instrument stable and stable, and reserve enough space in the length direction to meet the requirements of different test standards for the length of the sample. < /p >
< p > < strong > 2.2 clamping device design < /strong > < /p >
< p > taking account of the versatility of the instrument, it is necessary to design a fixture for clamping samples of different sizes, and it is easy to install and replace, while the test yarn is suspended with hooks, as shown in Figure 3. < /p >
< p > parallel chain type vernier is used to make the ruler slide up and down in the direction of the vertical sample. When the ruler is aligned with the lower end of the sample, the scale value at the end of the ruler is the length of the current sample. This test method is simple, fast and intuitive. < /p >
< p > < strong > 3 test results verify < /strong > < /p >.
< p > choose elastic resilience test ASTM D 3107 as validation project, and compare the data with the strength test method and the textile elongation recovery tester designed in this paper. < /p >
< p > < strong > 3.1 test steps < /strong > < /p >
< p > (1) selects 4 pounds of rated load; < /p >
< p > (2) set the following speed 10mm/min on the powerful machine, follow the range 0.5N; < /p >
< p > (3) record the elongation and relaxation of specimens after loading 30min, and the recoverability of samples after 30s; < /p >
< p > (4) used the strength tester and the textile yarn elongation recovery tester respectively to compare the same samples. < /p >
< p > < strong > 3.2 test results and analysis < /strong > < /p >
< p > using two kinds of instruments respectively to test, the data obtained, the data measured by two different instruments are basically the same, and the working principle of the textile yarn elongation recovery tester developed in this paper is also in line with the testing and standard requirements. Comparing the same sample, the data obtained are stable. < /p >
< p > < strong > 4 Conclusion < /strong > < /p >
< p > test shows that the textile yarn elongation recovery tester discussed in this paper has the following advantages and characteristics: < /p >
< p > (1) the scope of application is broad and versatility, and the testable standards are GB/T6506 - 2001, FZ/T 70001 - 2003, FZ/T 01034 - 2008, FZ/T 70006 - 2004, etc. < /p >
< p > (2) the structure is simple, convenient to maintain and low in use cost; < /p >
< p > (3) energy conservation and environmental protection, simple operation and stable data; < /p >
< p > (4) avoids the instability caused by the magnitude and speed of the test load in the sensor following method. < /p >