Many granulation equipment failures are not sudden, but rather caused by the accumulation of daily small problems. Daily system checks can effectively reduce unplanned downtime and maintenance costs, and extend equipment lifespan.
1、 Check the electrical control cabinet and wiring
Electrical system failures often cause the entire line to shut down, and troubleshooting takes a long time. Check the following items first every day:
✅ Check if the cooling fan of the control cabinet is running normally and if the temperature inside the cabinet is too high.
✅ Is the junction box cover of the main motor and feeding motor tightly closed to prevent dust from entering and causing short circuits.
2、 Check the fixing condition, temperature deviation, and short circuit of the thermocouple
The common cause of temperature fluctuations in granulators is not damage to the heating coil, but rather the thermocouple not being fully inserted or the fixing screws being loose. Check daily whether the thermocouple in each heating zone is securely inserted into the temperature measuring hole, and observe the deviation between the actual temperature displayed by the temperature control instrument and the set value. The normal temperature difference should be controlled within ± 5 ℃.
Check if the thermocouple is short circuited. If the temperature control instrument displays abnormal high temperature or rapid jumping, it may be caused by a short circuit in the thermocouple. A multimeter should be used to measure its resistance value for confirmation. If there is a short circuit, it should be replaced immediately.
If the temperature rise in a certain heating zone is significantly slow, a clamp meter can be used to measure the current. If there is no current display, it indicates that the heating coil has burned out and needs to be replaced in a timely manner.
Check the gearbox oil level daily to ensure that the oil mirror displays at 1/2 to 2/3 and the oil color is transparent amber. Low oil level can cause dry grinding of gears and bearings, which can result in damage in a short period of time; If the oil level is too high, the heat dissipation will be poor, and the increase in oil temperature will cause the viscosity to decrease.
Check whether the oil seal leaks oil, and observe whether there are any oil leakage marks on the joint surfaces and shaft ends of the gearbox. Check if the oil pump is running normally, listen for any abnormal noise, and confirm that the inlet and outlet pressures of the oil pump are within the normal range. Check for leaks in the water-cooled connector to ensure that the cooling water circuit is unobstructed and the joints are not loose.
If the oil appears milky white, it indicates that water has leaked into the cooler; If the oil turns black and contains metal powder, it indicates that the gear has experienced abnormal wear. The above two situations must be immediately stopped for handling and cannot continue to operate.
4、 Check the connection seal between the screw and the barrel
The connection flange between the screw and the barrel, and the joint surface between the machine head and the mold body are the locations where material leakage is prone to occur in daily production. Check each joint surface daily for any signs of melt leakage. When there is slight leakage, try tightening the bolts; If there is severe leakage, it is necessary to shut down and disassemble for cleaning, check whether the sealing gasket is damaged or aged, and replace it if necessary.
Long term material leakage not only wastes materials, but may also block the heating coil due to material carbonization, affecting temperature control accuracy.
5、 Listen to the sound of the device running and check for vibration
When the equipment is operating normally, it emits a stable low-frequency running sound. When the following abnormal sounds or vibrations occur, it indicates the presence of a potential fault:
✅ Periodic "clanging" sound: wear of the screw check ring or presence of metal foreign objects in the barrel.
✅ High frequency whistling sound: The gap between the cutting blade and the template is too small, or the bearing is dry and worn due to lack of oil.
✅ The whole machine shakes violently: the coupling is not concentric, or the feeding screw is bent.
✅ Gearbox abnormal noise: indicates bearing wear and needs to be checked and replaced in a timely manner.
✅ Motor abnormal noise: The bearing may be damaged and should be replaced in a timely manner.
