The precision spring with small load and high stiffness is the most important to the equipment, and the biggest requirement is that the test accuracy should be high, because in the test, small displacement changes will cause great changes in the testing machine. Although it is easy to ensure the testing accuracy of the testing machine, the key to ensure the accuracy of spring testing is to control the accuracy of parameter displacement of spring testing machine, which also means whether the accuracy of spring testing machine is standard.
The testing machine mainly uses servo motor as power source, screw and screw nut as executive parts to realize the speed control of moving beam. In the transmission control, there are mainly two forms, synchronous belt and reducer. In China, the testing machine manufacturers in Changchun area mostly use synchronous belt, while the testing machine manufacturers from Hongshan mostly use reducer. Its advantages and disadvantages need to be discussed, but they do not affect the use of users. In force measurement, load sensors are used in all electronic universal testing machines.
Therefore, more and more users regard the accuracy of displacement test as the standard to measure the level of testing machine. In the national standard of spring testing machine, the requirement of displacement accuracy is very low, which can not meet the requirement of precision spring with large stiffness. Therefore, for the manufacturer of test mechanism, it is necessary to improve the accuracy of displacement test to meet the requirements of users. There are many factors that affect the accuracy of displacement measurement, such as the detection method, the structure of the whole machine, the stiffness of the whole machine, the parallelism of the pressure plate, the measuring elements, materials, load displacement sinking, etc. as long as these factors are overcome, the guarantee of displacement accuracy is not a problem.
With the development of computer technology, the disadvantage of simple function of single chip microcomputer has been improved by microcomputer. Intelligent function setting expert system, parameter selection, database, clear Chinese interface of windows and simple mouse operation make it possible to achieve the most ideal state in the process of spring test, and the intelligent level has been greatly improved. The operator only needs to click the mouse, It can be measured and controlled according to any preset mode. By setting different test speed and parameters in the test process, the test mode and the whole test process can be controlled according to people’s will. The test curve and test data can be displayed in real time. The test data can also be calculated, sorted out and output according to the industry standard or enterprise standard, and the previous test data can be calculated, sorted out and output according to the industry standard or enterprise standard The powerful function of calculation and mathematical statistics has replaced the complicated work in the past and greatly reduced the amount of human labor.
The spring testing machine detects the displacement in strict accordance with the standard, which can ensure that the spring is placed in different places of the pressure plate, and the test force is basically the same, and any load will not cause the displacement sinking of the load sensor within the full range of the test force. In addition, the influence of loading method of spring testing machine on the test results can not be ignored. The early loading method mainly used the common AC motor to drive the transmission system to load, and the loading speed could not be adjusted. For the spring and other elastic components, due to the existence of rebound stress, the data collected automatically during fast compression is quite different from the data collected by slow compression or static compression. Now, variable speed systems, such as AC servo speed regulating system, are used to simulate the spring realistically The internal stress of the spring in this state is measured to provide the basis for the spring design.