How to adjust the universal testing machine at dif

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How to adjust the universal testing machine at different levels

nowadays, more and more plastic processing enterprises are buying the so-called universal testing machine "universal" testing machine, and using it to carry out tensile, bending, compression and shear tests, so as to evaluate the performance of materials, apply development research and quality control. Developed electronics have improved the performance of these devices, making them easier to operate and cheaper

the universal testing machine stretches, bends, compresses or pulls the plastic material spline through the adjustment of different speed levels. This is the smoothness of the plastic mixing laboratory film. The important thing is that it is the most common equipment to complete the maintenance and upgrading in the future by adding the slippery agent. In the preparation of mixed ingredients, the use of test materials can determine whether the materials are suitable for some specific processing applications or terminal applications. It can also be used for product quality control to ensure the consistency of product quality between batches

the universal testing machine includes one or more vertical bearing columns, on which a fixed horizontal base is installed, and a movable horizontal crosshead (cross beam) is on the top. In today's universal testing machine, there are usually ball screws on the columns to fix the movable crosshead. The universal test was shocked by the shiny, smooth surface similar to the original material. The size of the machine was jointly characterized by the maximum bearing level of the frame and the dynamometer for measuring load/tension. The dynamometer is attached to a movable crosshead driven by an electric motor or hydraulic device

a series of dynamometers with clamps measure the force, and the results can be displayed through a digital display or PC. Many universal testing machines have interchangeable dynamometers, so they can match the different materials tested. The static test is carried out by standard electronic universal testing machine, and the loading speed range is usually 0.001~20 in/min(1in.=2.54cm)。 Dynamic test or cyclic test, such as crack growth and fatigue test, are usually carried out by universal testing machine of hydraulic servo system, with long time and low load. At present, the most common items tested by universal testing machine are tensile strength and tensile modulus, bending strength and modulus. When the tensile test is carried out according to ASTM D 638 and ISO 527, both ends of the spline are clamped by clamps. One clamp is stationary, the other is fixed on the crosshead, moves away from the fixed clamp, and pulls the spline until the spline breaks. When the crosshead control accuracy and quality are greatly improved, it will automatically stop. During the bending test (ASTM D790, d6272 and ISO178), the spline is placed on the two supports of the fixed machine tool of the testing machine. In this test, the moving direction of the crosshead is opposite to that in the tensile test, pushing the spline towards an unsupported center rather than pulling it until the spline bends or even breaks. Because most thermoplastic materials will not break in this test, it is impossible to calculate the breaking bending strength. Therefore, the standard test method requires calculating the bending stress when the strain is 5%. The capacity of the commonly used electronic universal testing machine is 100 ~ 135000lb. The larger the size, the higher the cost. Generally speaking, the vertical equipment is smaller and easier to operate, and with the help of the gravity of the sample itself, thorny samples such as films can also be controlled as easily as heavy injection molded parts. The force range and price of the single column universal testing machine are low, and the structural capacity is generally 1000 lb. The structural capacity of the gantry universal testing machine can reach 1000~135000 lb. The dynamometer is also based on a certain maximum force value applicable to the structure of the universal testing machine and samples. For example, a 100 LB dynamometer installed in a 1000 LB mold frame can provide a 100 LB test load. The capacity of the dynamometer should not exceed the predicted breaking load of the sample too much, otherwise the accuracy of the test results will be affected

unlike the universal testing machine used for static testing, the hydraulic servo universal testing machine can carry out dynamic testing and fatigue testing. In this way, the stress must be applied repeatedly to carry out the load release cycle

for example, in fatigue crack growth test, users expect to know how many cycles the material to be tested will break. The stress required for dynamic testing of universal testing machine is smaller than that required for static testing of electronic universal testing machine. The frame capacity of hydraulic servo system testing machine ranges from 100 lb to several tons, and the price is usually 2-3 times that of electronic mechanics testing machine. It is basically used for fatigue test of metal materials, but it is also widely used in automotive plastics, aerospace plastics, biomedical plastics and plastics for electronic components, because structural components with good fatigue resistance are needed in these fields. (end)

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