Common fault 1 of pendulum impact tester: poor sensitivity of dial pointer, midway stop after unloading, or constant change of zero position. There are many reasons for this phenomenon.
1. The pulley and track on the gear rod are too dusty and rusted. At this time, it is necessary to remove and clean it, and add a little clock oil.
2. The pointer rotating shaft is dirty and should be cleaned.
3. There is contact between the tooth bar pressing plate and the tooth bar, which should be loosened.
4. The oil return of the buffer is poor and should be adjusted or cleaned.
5. The belt on the force-measuring piston falls off or is too loose (making the piston unable to run at a uniform speed).
6. If the friction force of the force-measuring piston in the oil cylinder increases or gets stuck, use chromium oxide grinding paste to grind it until it is normal.
7. There are obstacles in the lifting process of the pendulum, or the pendulum shaft is too dirty or rusty, which makes the pointer return to zero and change greatly.
The second common fault of the pendulum impact tester is that the fracture of the sample is always broken on both sides during the tensile test. The reason for this phenomenon should first consider whether the main part of the testing machine is installed vertically. If this reason is excluded, it should be eliminated from the following three aspects.
1. The jaw is not placed correctly when clamping, and the sample shall be clamped symmetrically according to the requirements.
2. The jaw quality is poor and the teeth are damaged, which not only affects the different centers of the jaw, but also makes the sample slip during the test, making the yield point difficult to identify. At this time, replace the jaw.
3. The lifting guide wheel is not adjusted correctly, so that the upper and lower jaws are not concentric. One inspection rod shall be machined. After the upper and lower jaws are tightened, measure with a dial indicator based on two force columns until the adjustment is qualified.
The third common fault of the pendulum impact tester is that the position of the pendulum is abnormal and the pendulum rod is not aligned vertically. The main reason is that the viscosity of the oil is too large or the oil is too dirty. Troubleshooting: replace the oil with proper viscosity. The force measuring piston rotates with great friction or does not rotate. Troubleshooting: check whether the impact tester is horizontal and eliminate the failure of the force measuring piston. There is unstable friction. Troubleshooting: clean the cycloidal shaft bearing, gear rod, pointer and wire wheel, adjust the level of the testing machine, and reduce the existing unstable friction.
The fourth common fault of pendulum impact tester is that the return of the hammer is abnormal, fast and slow. Generally, just turn the buffer to the proper position. However, if the oil hole of the buffer is blocked, or there is dirt or excessive clearance between the steel ball of the buffer valve and the inlet, the buffer will fail. The solution is to clean the buffer valve and adjust the clearance between the steel ball and the valve seat to about 0.5mm. Place the oil needle knob to reduce the clearance between the oil needle and the valve body, and list the weight mark again. In addition, when the temperature has a great impact, the oil can be replaced appropriately.
