Influence Factors of Performance and Precision of Electronic Universal Testing Machine

The universal testing machine is easy to use, has no pollution, and has high efficiency. It is widely used in the testing of tensile properties of various metals, non-metals, foods, medicines and other industries. Frequently using electronic universal testing machines knows that product performance and precision can determine the test results. However, there are often factors that can lead to inaccurate data. The following Xiao Bian introduces several factors that affect the performance and precision of the electronic universal testing machine.

1. The parts of the electronic universal testing machine that drive the sensor's motion are the ball screws. If there is any gap in the screw, the test data will be directly affected, which will directly affect the maximum deformation and elongation after breaking. At present, the electronic universal testing machine on the market has some screws that use T-shaped ordinary screw rods. In this case, first, the gap is relatively large, and second, the friction force is relatively short and the service life is short.

2. The transmission system of the electronic universal testing machine. At present, the testing machine transmission system on the market adopts some speed reducers, and some use ordinary belts. The main disadvantages of these two transmission methods are: the former needs regular lubrication, the latter is The synchronization of the drive cannot be guaranteed to affect the test results. The testing machine transmission system of open source instrument adopts full arc synchronous belt deceleration to ensure the synchronization precision of transmission, high transmission accuracy, high efficiency, smooth transmission, low noise, no need for long service life, and force sensor of testing machine. Because the quality of the sensor determines the accuracy of the testing machine and the stability of the force measurement, the current sensor on the market generally uses S-type sensors for small forces, spoke-type sensors for general value, and generally strain gauges for internal sensors. If the accuracy of the strain gauge is not high or the anti-aging ability of the fixed strain gage is not good or the sensor's material is not good, it will affect the accuracy and service life of the sensor. The imported sensors used by open source instruments are American 铨 force sensors manufactured by world-renowned sensor manufacturers. The sensor has high accuracy, good linearity, and very stable performance, and will not change for decades.

4. The power source (motor) of the testing machine is also called a motor. Currently, some testing machines on the market use common three-phase motors or variable-frequency motors. This type of motor uses analog signal control, slow control response, inaccurate positioning, and general speed range. narrow. There is no high speed, no low speed or low speed, no high speed, and inaccurate speed control. The open source instrument uses Panasonic full digital AC servo motor. The control method adopts all-digital pulse control, and the speed range is wide, up to 0.001. -1000MM/MIN, control positioning accuracy, fast response, 0.01 seconds can be added to full speed, the motor can ensure full-scale speed control accuracy, and long life, up to several decades, and no maintenance.

5, testing machine control system (that is, software and hardware), the current market, most of the tensile machine measurement and control system using 8-bit microcontroller control, low sampling rate, and poor anti-interference ability, the other is the AD converter, If the AD converter has a low resolution, the resolution is low. Then the measurement will not be accurate. The open source instrument measurement and control system adopts Hytest V6.0, the controller developed by the world's most advanced 32-bit ARM technology. This controller is based on the 32-bit ARM platform and runs the company's time-and-multitasking operating system, which is a more stable program operation. The system is more stable. Sampling rate up to 200 times per second, plus 24-bit high-precision low-noise sound high-speed AD converter, so that the entire measurement and control system more high-precision, high-stability control of the entire test process, the host computer software for the open source device lasted Two years of development of the full digital three-loop control software, there are two control methods a. PID control adjustment method b. Model Lake control adjustment method (the industry's first). The entire test process can achieve constant force value control, constant displacement control, constant deformation control, low frequency fatigue control, and program arbitrary control.

Therefore, the components of the ball screw, transmission system, force sensor, power source, and measurement and control system that drive the motion of the sensor will affect the performance and precision of the electronic universal testing machine, resulting in inaccurate measurement results. These five parts are the core technical parts of the electronic universal testing machine. Only when these parts are given the right medicine to improve their performance, can the performance of the universal testing machine be greatly improved, so that the experimental results of the universal testing machine will be more effective. Accurate, the quality of the materials tested will be closer to the facts.