Common failures and repairs of twin-screw extruder
Common failures and repairs of twin-screw extruderTwin-screw extruders often have some faults in use. The general troubleshooting can be repaired quickly based on experience. Here are some common experiences for your reference!
1. The host current is unstable
1. Reasons for production:
(1) The feeding is uneven.
(2) The main motor bearing is damaged or poorly lubricated.
(3) A certain section of heater fails and does not heat.
(4) The screw adjustment pad is wrong, or the phase is wrong, and the component interferes.
2. Treatment method:
(1) Check the feeder and eliminate the fault.
(2) Repair the main motor and replace the bearings if necessary.
(3) Check whether each heater is working normally, and replace the heater if necessary.
(4) Check the adjustment pad and pull out the screw to check whether the screw interferes.
2. The main motor cannot be started
1. Reasons:
(1) The driving procedure is wrong.
(2) There is a problem with the main motor thread. Is the fuse wire burned?
(3) Interlocking devices related to the main motor function
2. Treatment method:
(1) Check the procedure and restart the vehicle in the correct driving order.
(2) Check the main motor circuit.
(3) Check whether the lubricating oil pump is started, and check the status of the interlocking device related to the main motor. The oil pump does not turn on, and the motor cannot turn on.
(4) The induction power of the inverter is not discharged, turn off the main power supply and wait for 5 minutes before starting.
(5) Check whether the emergency button is reset.
Third, the machine head is not smooth or blocked
1. Reasons:
(1) A certain section of the heater does not work, and the material is poorly plasticized.
(2) The operating temperature setting is low, or the molecular weight distribution of the plastic is wide and unstable.
(3) There may be foreign objects that are not easily melted.
2. Treatment method: (1) Check the heater and replace it if necessary.
(2) Verify the setting temperature of each section, and consult with the technician if necessary to increase the temperature setting value. (3) Clean and inspect the extrusion system and the machine head.
4. The starting current of the main power is too high
1. Reasons:
(1) The heating time is insufficient and the torque is large.
(2) A certain section of heater does not work.
2. Treatment method:
(1) Use a handcart when driving. If it is not easy, extend the heating time or check whether the heaters of each section work normally.
5. The main motor makes an abnormal sound:
1. Reasons:
(1) The main motor bearing is damaged.
(2) A thyristor in the thyristor rectifier circuit of the main motor is damaged. 2. Treatment method:
(1) Replace the main motor bearing.
(2) Check the silicon controlled rectifier circuit, and replace the silicon controlled element if necessary.
6. The temperature rise of the main motor bearing is too high:
1. Reasons:
(1) Poor bearing lubrication.
(2) The bearing is badly worn.
2. Reasons:
(1) Check and add lubricant. Check the motor bearings and replace if necessary.
Seven, the head pressure is unstable:
1. Reasons:
(1) The speed of the main motor is uneven.
(2) The speed of the feeding motor is uneven, and the feeding amount fluctuates.
2. Treatment method:
(1) Check the main motor control system and bearings.
(2) Check the feeding system motor and control system.
8. Low lubricating oil pressure:
1. Reasons:
(1) The pressure setting value of the lubricating oil system pressure regulating valve is too low.
(2) The oil pump is faulty or the oil suction pipe is blocked.
2. Treatment method:
(1) Check and adjust the pressure regulating valve of the lubricating oil system.
(2) Check the oil pump and oil suction pipe.
Nine, the speed of the automatic screen changing device is slow or not working 1, the reasons:
(1) Low air pressure or oil pressure.
(2) Air leakage (or oil leakage) from the cylinder (or hydraulic station).
2. Treatment method:
(1) Check the power system of the screen changer.
(2) Check the sealing of the cylinder or hydraulic cylinder.
10. Safety pin or safety key is cut off
1. Reasons:
(1) Excessive torque of extrusion system
(2) The connection between the main motor and the input bearing is not concentric
2. Treatment method:
(1) Check whether metal and other objects in the extrusion system enter the stuck screw. At the beginning, check whether the preheating temperature rise time or temperature rise value meets the requirements.
(2) Adjust the main motor
11. The extrusion volume suddenly drops:
1. Reasons:
(1) The feeding system fails or there is no material in the hopper.
(2) The extruding system enters the hard screw and prevents the material from passing through.
2. Treatment method:
(1) Check the material level of the feeding system or hopper.
(2) Check and clean the extrusion system.
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