As the core equipment of industrial production, the efficient operation of screw extrusion granulator relies on standardized operation and meticulous maintenance. Improper operation not only affects product quality, but may also cause equipment failure or safety accidents. This article will sort out several common faults and their solutions to help you achieve safe and efficient production.
The common faults and solutions of screw extrusion granulator are as follows:
1、 Abnormal discharge problem
Performance: Irregular particle shape, fluctuating discharge speed, or complete cessation of discharge.
Solution:
Check if the feeding system is unobstructed and confirm if the raw materials meet the specifications.
Observe whether the cutting device is working properly and whether the degree of blade wear affects the cutting effect.
Check if the template holes are blocked, which is a common cause of poor discharge.
2、 Abnormal vibration of equipment
Performance: Abnormal vibration of the device.
Solution:
Check if the fixing bolts of the equipment base are loose and if the foundation is stable.
Check whether the spindle bearings are worn, which is one of the main factors causing vibration.
Check whether the rotor dynamic balance is out of balance and whether the transmission components are well aligned.
3、 Temperature control system malfunction
Performance: The heating temperature is unstable or cannot reach the set value.
Solution:
Check if the thermocouple is damaged and if the temperature sensor is installed in the correct position.
Check the working status of the heating coil and confirm that each heating coil can generate heat normally.
Check if the cooling system is unobstructed and if the flow rate of the cooling medium is sufficient.
4、 Electrical control system malfunction
Performance: motor overload, control system failure, and other issues.
Solution:
Check if the power supply voltage is stable and if all wiring terminals are secure.
Check the operating status of the PLC controller and confirm if the program settings are correct.
Check whether various protective devices are functioning properly, such as overload protection, temperature protection, etc.
5、 The main motor cannot start
Reason: Driving program error; There is a problem with the main motor thread, and the fuse has been blown; The interlocking effect of the lubricating oil pump motor has not been released; The induction power of the frequency converter has not been fully discharged; The emergency button has not been reset.
Solution: Check the program and restart driving in the correct order; Check the main motor circuit; Check whether the lubricating oil pump is started and the status of the interlocking device related to the main motor; Turn off the main power and wait for 5 minutes before restarting; Check if the emergency button has been reset.
6、 The main motor current is unstable
Reason: Uneven feeding; Damaged or poorly lubricated main motor bearings; A certain section of the heater is malfunctioning and not heating up; The screw adjustment pad is incorrect, or the phase is incorrect, and the components interfere.
Solution: Check the feeder and troubleshoot the issue; Repair the main motor and replace the bearings if necessary; Check if each heater is working properly and replace it if necessary; Check the adjustment pad and pull out the screw to check for any interference.
7、 The starting current of the main motor is too high
Reason: Insufficient constant temperature time after heating and high torque; A certain section of the heater is not working.
Solution: When driving, use a hand crank. If it is not easy, extend the heating time or check if each section of the heater is working properly.
8、 Abnormal working sound of electric motor
Reason: The carbon brush is severely worn; Bearing damage; The thyristor component has malfunctioned.
Solution: Replace the carbon brush; Replace bearings; Check the thyristor rectifier circuit and replace the thyristor components if necessary.
9、 The temperature of the motor bearing position is too high
Reason: Insufficient lubricating oil; Severe bearing wear; The rotor shaft is bent and deformed.
Solution: Add lubricating oil; Replace bearings; Correct or replace the rotor shaft.
10、 The screw rotates unstably during operation
Reason: The screw driven motor rotates unstably; The fluctuation error of heating temperature is large; There is blockage in the inner cavity of the machine head mold; Uneven plasticization of materials.
Solution: Check and repair the screw drive motor; Stable heating temperature; Clean the inner cavity of the machine head mold; Adjust the material plasticization process.
11、 The safety pin is broken
Reason: Breaks while driving, mostly due to insufficient heating process temperature and constant temperature time, and insufficient plasticization of materials; Breaks during normal production may be caused by metal foreign objects mixed into the material, jamming the screw, or low process temperature resulting in poor plasticization of the material.
Solution: Ensure that the constant temperature time of the heating process temperature is sufficient; Check for foreign objects in the material and clean the screw; Properly increase the process temperature.
12、 Insufficient oil supply in the lubrication system
Reason: The oil pump has severe wear and tear; The oil suction pipeline is blocked by foreign objects.
Solution: Replace the oil pump; Clean up foreign objects in the oil suction pipeline.
13、 The discharge of the machine head is not smooth or blocked
Reason: A certain section of the heater is not working, resulting in poor plasticization of the material; The operating temperature is set too low, or the molecular weight distribution of the plastic is wide and unstable; There may be foreign objects that are not easily melted.
Solution: Check the heater and replace it if necessary; Verify the temperature settings for each section and, if necessary, consult with the process engineer to increase the temperature settings; Clean and inspect the extrusion system and machine head.
14、 The output of the extruder has decreased
Reason: There is a "bridging" phenomenon in the hopper, resulting in insufficient feeding; The feeding screw speed is low and the feeding amount is small; The machine head mold is clogged with foreign objects.
Solution: Check the hopper and eliminate the phenomenon of "bridging"; Increase the speed of the feeding screw; Clean the machine head mold.
15、 Equipment abnormal vibration handling plan
Performance: Abnormal vibration of the device.
Solution:
The concentricity error between the motor and the spindle is usually required to be controlled within 0.05mm when using a laser alignment instrument.
If the bearing wear exceeds 30% of the design clearance, the high-precision self-aligning roller bearing should be replaced immediately.
When the material filling rate fluctuates by more than 15%, it can also cause abnormal vibration. It is recommended to install an online density monitoring device.
16、 Main motor overheating prevention strategy
Performance: The main motor is overheated.
Solution:
Regularly clean the aggregates in the cooling air duct, and it is recommended to use compressed air for blowing every month.
Check if the output waveform of the frequency converter is normal to prevent additional heating caused by harmonic interference.
Using infrared thermal imaging technology to monitor winding temperature and setting multi-level warning thresholds.
17、 Solution for Poor Plasticization of Materials
Performance: The tablet particles exhibit density stratification.
Solution:
Prioritize investigating the heating zone control module of the twin-screw granulator equipment.
Use an oscilloscope to test the voltage stability of each heating zone, ensuring that the temperature difference fluctuation does not exceed ± 3 ℃.
In response to insufficient material retention time, the conveying efficiency can be optimized by adjusting the screw combination configuration.