1. There is excessive dust and rust on the pulley and track on the gear rod. At this point, it is necessary to remove and clean it thoroughly, and then add a small amount of clock oil.

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

3. If there is contact between the toothed rod pressing plate and the toothed rod, it should be loosened.

4. Poor oil return of the buffer should be adjusted or cleaned. (Refers to the blockage of a curved road)

5. The belt on the force measuring piston falls off or becomes too loose (preventing the piston from running at a constant speed).

6. If the friction force of the force measuring piston increases or gets stuck in the oil cylinder, apply chromium oxide grinding paste to grind it until it is normal.

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

Common faults: Sometimes when loading, the maximum load cannot be reached or unloading occurs during the loading process. This type of malfunction occurs frequently and has multiple causes.

1. The viscosity of the oil is too low (oil keeps flowing out of the return pipe of the oil delivery valve during loading). Generally, medium viscosity mineral oil is used, which does not contain water, acid, or other mixtures. It does not decompose at room temperature and does not thicken. If necessary, a viscosity meter can be used for measurement. If oil is used improperly, it can cause valve and oil circuit blockage, and may cause vibration or pipeline leakage. It is best to use oil according to the instructions.

2. The oil pressure system is severely leaking oil. Oil leakage in the oil circuit system usually occurs at the connection between the buffer valve, return valve, delivery valve, oil pump, and pipeline. After adding gaskets, tighten the screws. If the sealing gasket is damaged, it must be disassembled here and replaced with a new one. The gasket should be made of copper or aluminum alloy.

3. Insufficient fuel level in the fuel tank. When loaded to a certain load, there is a "plop" or "plop" sound in the return pipe of the oil delivery valve, and there is little oil output and bubbles. When the load cannot rise any further, there is no oil flowing out of the return pipe. Exclusion method: Fill the oil tank of the testing machine with oil until the oil level reaches half of the sight glass.

4. The oil collector of the oil pump is not tightly pressed onto the pump body. In this way, each loading can only reach a certain load, and the load cannot rise any further. There is no oil flowing out of the return pipe of the oil delivery valve. Exclusion method: Use a wrench to tighten the fixing screws at the rear of the oil pump. If there are still problems, remove the oil collector and add a gasket between the oil collector and the pump body.

5. The clearance between the working piston and the oil cylinder is too large, and there is excessive oil leakage from the clearance, which can be seen from the oil overflow outlet. The solution is to increase the viscosity of the oil. If the problem still cannot be solved, after precise measurement, the piston and cylinder should be replaced at the production plant.

6. The clearance between the force measuring piston and the force measuring cylinder is large, which can be seen from the lower part of the force measuring cylinder when it reaches a high tonnage. Under normal circumstances, there is no visible oil dripping or intermittent oil dripping at high tonnage. If it flows out in a linear pattern, it indicates that the force measuring piston should be replaced. When observing oil leakage, attention should be paid to the difference between joint oil leakage and cylinder plug oil leakage, and incorrect judgments should not be made due to misreading.

7. The piston and piston sleeve in the oil delivery valve are damaged or the spring has become soft. In this way, the load that can be achieved each time is basically unchanged, and the noise of the oil delivery valve is loud. When the load cannot rise any further, the oil output of the oil return pipe of the oil delivery valve is large. The piston and piston sleeve should be removed and ground, and if the damage is severe, the spring should be replaced.

8. The stiffness of the stabilizing spring of the oil delivery valve is low or the cavity of the throttle needle is blocked. Main manifestation: Each loading can only reach a certain load, and when the load cannot rise any further, the oil return pipe will produce a large amount of oil. Exclusion method: Replace the stabilizing spring with a suitable stiffness or clean any dirt.

9. The gap between the damping needle and the damping hole of the oil delivery valve is too small. Main manifestation: Each loading can only reach a certain load, and when the load cannot rise any further, the oil output of the return pipe of the oil delivery valve is large. Exclusion method: Remove the damping needle and file off a portion along the axis of the damping needle with a file.

10. The belt that drives the oil pump is loose and slipping. After being loaded to a certain load, it cannot rise again. There is no oil flowing out of the return pipe of the oil delivery valve, and the oil pump has no working sound. Exclusion method: Loosen the fixing screws of the motor, adjust the position, tighten the belt, and then tighten the fixing screws of the motor. If the belt deforms too much, a new belt needs to be replaced.

11. The oil pump plunger is corroded. Main manifestation: During the loading process, there may be discontinuous or fluctuating oil output from the return pipe of the oil delivery valve. When a certain load cannot be increased any further, there is no oil flowing out of the return pipe. Exclusion method: Remove the plunger and re polish it.

12. Testing machines with safety valves can automatically open when the maximum load exceeds 3% to 5%, ensuring that the testing machine is not overloaded and damaged. If the safety valve is not adjusted properly or the valve tip and hole are not tightly closed, the pressure will not be high. The adjustment method is to remove the safety valve adjustment screw, check the damage of the parts, and replace them. If the overload is too high, turn the screw downwards, and vice versa.

Common faults: During the loading process of the testing machine, the body vibrates, the pointer rotates unstably, and the values cannot be accurately read. There are many situations where this reason arises.

Firstly, potential sources of resonance around the testing machine should be eliminated, and then the installation foundation of the machine should be observed for firmness, and the motor should be checked for any malfunctions. After solving these problems, if there is still pointer instability, then it is necessary to consider whether there is air present in the oil system. The method is to start the oil pump, close the return valve, raise the main piston to a certain height, and then open the return valve to allow oil to flow back from the oil pump main cylinder to the oil tank through the return valve. After circulating for a period of time, the air inside the main oil cylinder can be completely expelled. Unscrew the screw of the exhaust hole of the oil collection tank again, and tighten it when the oil that comes out is free of bubbles. In addition, the high-pressure oil pipe of the oil pump can be removed and the motor can be started to remove the air inside the oil pump. Long term use of testing machines should regularly change the oil and clean the gear bars, gears, pointers, and wire wheels of the force measuring part. (It should be noted here that the diameter of the replaced string wire should meet the requirements every time the wire wheel is cleaned, and the direction and number of turns of the wire wheel should be appropriate.) Oil that is too dirty can sometimes change the balance of the oil delivery valve pressure due to blockage by debris, resulting in uneven oil circulation. The uneven length of the two triangular belts connecting the oil pump, as well as the abnormal operation of the plunger in the oil pump or the different clearances between the seven sets of oil distribution valves, can cause vibration in the testing machine.

Common malfunction: During tensile testing, the fracture surface of the specimen always breaks on both sides. The reason for this phenomenon should first consider whether the installation of the main body of the testing machine is vertical. If this reason is eliminated, it should be eliminated from the following three aspects.

1. If the jaws are not aligned properly during clamping, the specimen should be clamped symmetrically according to the requirements.

2. Poor quality of the jaws and damaged teeth not only affect the misalignment of the jaws, but also cause the specimen to slip during the testing process, making it difficult to identify the yield point. At this point, the jaws should be replaced.

3. The adjustment of the lifting guide wheel is not correct, causing the upper and lower jaws to be misaligned. An inspection rod should be processed, and after tightening the upper and lower jaws, two force columns should be used as a basis to measure with a dial gauge until the adjustment is qualified.

Common faults: The position of the pendulum is abnormal, and the pendulum rod cannot be aligned vertically.

The main reason is that the viscosity of the oil is too high or the oil is too dirty. Exclusion method: Replace the oil with a suitable viscosity.

The force measuring piston rotates with significant friction or does not rotate. Exclusion method: Check if the testing machine is level and eliminate the fault of the force measuring piston.

There is unstable frictional force. Exclusion method: Clean the swing shaft bearing, gear rod, pointer, and wire wheel, adjust the level of the testing machine, and reduce the unstable friction force that exists.

Common malfunction: The hammer returns abnormally, sometimes fast and sometimes slow.

Normally, simply rotate the buffer to the appropriate position. However, if the oil hole of the buffer is blocked, or if there is dirt or excessive clearance between the steel ball of the buffer valve and the inlet, it will cause the buffer to malfunction. The solution is to clean the buffer valve and adjust the gap between the steel ball and the valve seat to about 0.5mm. Place the oil needle knob to reduce the gap between the oil needle and the valve body, and re list the markings of the A.B.C. weights. Also, when the temperature has a significant impact, the oil can be replaced appropriately.

Common malfunction: The passive needle cannot stop well at any position and does not coincide with the main needle.

The elimination method is to remove the dial glass, adjust the passive needle compression spring screw, and adjust the pointer to coincide with the main needle.

Common faults: During loading, the oil system leaks oil severely or the oil pipe ruptures.

Firstly, check if the joints of the oil system are tightened. If gaskets need to be replaced, they should be replaced in a timely manner. If the oil pipe ruptures, then a stronger oil pipe needs to be replaced. In addition, it is necessary to observe whether the oil delivery valve and overflow valve pistons are stuck or installed backwards.

Common malfunction: After the sample breaks, the pendulum quickly falls back, causing impact.

The main issue is the failure of the buffer. In addition to making routine adjustments, consideration should also be given to whether the oil used is too thin or too dirty.

In short, it is important to regularly pay attention to the operating conditions of the testing machine. When it comes to the host, it is important to prevent eccentricity and avoid friction; For the force measurement part, prevent impact and dust from entering. Regularly inspect and calibrate the testing machine to ensure its normal use.