How to solve the fault problem of universal material testing machine

Universal material testing machineAlso known as universal tensile machine or electronic tensile machine. It features an independent servo loading system, high-precision wide-frequency electro-hydraulic servo valve, ensuring high efficiency, low noise, and fast response; it uses an independent hydraulic clamping system to ensure low noise and smooth operation, with the test sample firmly clamped during the testing process without slipping. The universal material testing machine uses a microcomputer-controlled fully digital wide-frequency electro-hydraulic servo valve to drive a precision hydraulic cylinder, with the microcomputer control system automatically controlling various modes of test force, displacement, and deformation, completing tensile, compression, and bending tests on samples, meeting the requirements of national standard GB/T228-2010 "Methods for tensile testing of metallic materials at room temperature" and other standard requirements.

Universal material testing machineThe electrical part includes a load measurement system and a displacement measurement system. All control parameters and measurement results can be displayed in real-time on the computer screen, allowing for the calculation of parameters such as elastic modulus, tensile strength, and elongation after fracture. It also has overload protection and other functions. So how to solve the faults that occur during the use of the universal material testing machine? Let's take a look at how to easily solve the fault problems of the universal material testing machine.

1.Universal material testing machineMain unit does not start

1. Exclude power line faults. Check if the power line is connected, and whether the connection is correct and secure.

2. Check if the 380V three-phase power socket is missing a phase, and if the power line has come loose.

3. Check if the emergency stop button has been pressed.

4. Check if the limit switch is open.

5. Check if the switch power supply is working normally. Measure the voltage at each output point of the switch power supply to see if it meets the requirements of the tensile testing machine.

2.Universal material testing machineThe dial pointer has poor flexibility, stops midway after unloading, or the zero position frequently changes.

1. Excessive dust and rust on the pulley and track of the rack. In this case, it needs to be removed, cleaned, and a small amount of clock oil added.

2. The pointer rotation shaft is dirty and should be cleaned.

3. There is contact between the rack pressure plate and the rack, which should be loosened.

4. Poor oil return condition of the buffer should be adjusted or cleaned. The return path may be blocked.

5. The belt on the measuring piston is loose or too slack, preventing the piston from operating smoothly.

6. Increased friction or jamming of the measuring piston in the oil cylinder, should be ground with chromium oxide polishing paste until normal.

7. There are obstacles during the lifting process of the pendulum, or the pendulum shaft is too dirty or rusty, causing large fluctuations in the pointer's return to zero.

3.Universal material testing machineDisplay overload

1. Check if the connection between the computer and the main unit of the testing machine is normal.

2. Check if the sensor was incorrectly selected during the connection.

3. Check if the sensor was bumped during keyboard operation or the last experiment.

4. Check if the calibration function of the software was used previously.

5. Check if the calibration value, standard value, or other information in the hardware parameters was manually changed.

4. The universal material testing machine unloads during the loading process (more common, with various reasons).

1. The gap between the oil delivery valve damping needle and the damping hole is too small. Each loading can only reach a certain load, and when the load cannot increase further, the oil delivery valve's return pipe has a large outflow. In this case, the damping needle needs to be removed and a portion should be filed along the axial direction.

2. Rust on the oil pump plunger can cause discontinuous or fluctuating oil delivery during loading. When the load cannot increase further, there is no oil flow from the return pipe. In such cases, consider removing the plunger for re-polishing during maintenance.

3. Insufficient oil level in the oil tank may also lead to the above faults. When the universal testing machine reaches a certain load, the oil delivery valve's return pipe may make a "puff, puff" sound, and there is little oil output with bubbles. When the load cannot increase further, there is no oil flow from the return pipe. Add oil to the testing machine's oil tank until the oil level reaches half of the sight window to eliminate the fault.

4. Improper adjustment of the safety valve or poor sealing between the valve tip and hole can also lead to the above faults. The solution is to disassemble the safety valve adjustment screw, check for damaged parts, and replace them. If overloaded, turn the screw down; otherwise, turn it up.

5. Excessive oil overflow from the universal material testing machine can be seen from the overflow outlet. Increase the viscosity of the oil; if the problem persists, after precise measurement, the piston and oil cylinder should be replaced at the manufacturer.

6. The belt driving the oil pump is loose, causing slippage. After reaching a certain load, it cannot increase further, and there is no oil flow from the oil delivery valve's return pipe, with no sound from the oil pump. The repair method is to loosen the motor fixing screws, adjust the position to tighten the belt, and then tighten the motor fixing screws. If the belt is too deformed, it needs to be replaced.

7. There is a large gap between the measuring piston and the measuring oil cylinder. When reaching high tonnage, it can be seen from the lower part of the measuring oil cylinder. Normally, there should be no dripping oil or intermittent dripping at high tonnage; if it flows out in a line, it indicates that the measuring piston should be replaced. When observing oil leakage, pay attention to the difference between joint leakage and cylinder leakage, and do not make incorrect judgments due to misinterpretation.

8. Using oil with too low viscosity can cause continuous oil flow from the oil delivery valve's return pipe during loading, leading to faults. The solution is to generally use medium viscosity mineral oil, free of water, acid, and other mixtures, which does not decompose or thicken at room temperature. If necessary, a viscometer can be used for measurement. Improper oil use can clog valves and oil paths, potentially causing vibrations or pipeline leaks. Oil should be used according to the manual's requirements.

9. The stiffness of the oil delivery valve pressure regulating spring is low or the throttle needle cavity is blocked. This fault causes the load to only reach a certain level each time it is loaded. When the load can no longer increase, the return oil pipe has a large output. At this time, consider replacing the pressure regulating spring with appropriate stiffness or cleaning the dirt.

10. The oil pressure system of the universal material testing machine has a serious oil leak. The main manifestation is that the oil leakage in the oil circuit system generally occurs at the connections of the buffer valve, return oil valve, oil delivery valve, oil pump, and pipelines. The solution is to tighten the screws after adding gaskets. If the sealing gasket is damaged, it must be disassembled and replaced with a new one. The gasket should be made of purple copper or aluminum alloy.

After reading the common faults and solutions shared with you,Universal material testing machinedo you have any questions about how to easily solve the fault problems of the universal material testing machine? If there are still unclear areas, please call for consultation.Tiancheng Testing Co., Ltd.Our company will arrange technical personnel to answer your questions one by one. We welcome your calls and support!