Common faults and solutions for extruders

Update:22 Oct 2021

There are about eleven common faults in the extruder. The following describes these eleven faults and troubleshooting methods in detail:
1. The temperature rise of the main motor bearing is too high:
  1. Reason:
   (1) The bearing is poorly lubricated.
   (2) The bearing is worn out seriously.
  2. Reason:
   (1) Check and add lubricant. Check the motor bearings and replace if necessary.
2. The head pressure is unstable:
  1. Reason:
   (1) The rotation speed of the main motor is uneven.
   (2) The speed of the feeding motor is uneven and the feeding amount fluctuates.
  2, processing method:
   (1) Check the main motor control system and bearings.
   (2) Check the feeding system motor and control system.
3. Low lubricating oil pressure:
  1. Reason:
   (1) The pressure setting value of the pressure regulating valve of the lubricating oil system is too low.
   (2) The oil pump is faulty or the oil suction pipe is blocked.
  2, processing method:
   (1) Check and adjust the pressure regulating valve of the lubricating oil system.
   (2) Check the oil pump and suction pipe.
Fourth, the automatic screen changer is slow or not working
  1. Reason:
   (1) Low air or oil pressure.
   (2) The cylinder (or hydraulic station) leaks air (or oil).
  2, processing method:
   (1) Check the power system of the screen changer.
   (2) Check the sealing condition of the cylinder or hydraulic cylinder.
5. The safety pin or safety key is cut off
  1. Reason:
   (1) Extrusion system torque is too large
   (2) The main motor and the input bearing are not connected
  2, processing method:
   (1) Check the extrusion system whether there is metal or other objects entering the jamming screw. At the beginning, check whether the warm-up time or the warm-up value meets the requirements.
   (2) Adjust the main motor
6. Sudden decrease in extrusion volume:
  1. Reason:
   (1) The feeding system fails or there is no material in the hopper.
  (2) The extrusion system enters into the hard and jammed screw, so that the material cannot pass through.
  2, processing method:
   (1) Check the material level of the feeding system or hopper.
   (2) Check and clean the extrusion system.
Seven, the host current is unstable
  1. Reasons for production:
   (1) Uneven feeding.
   (2) The main motor bearing is damaged or poorly lubricated.
   (3) A certain section of the heater fails and does not heat up.
   (4) The screw adjustment pad is wrong, or the phase is wrong, and the components interfere.
  2, processing method:
   (1) Check the feeder and troubleshoot.
   (2) Overhaul 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 if there is any interference in the screw.
8. The main motor cannot start
  1. Reason:
   (1) There is an error in the driving procedure.
   (2) There is a problem with the main motor thread, whether the fuse is burned.
   (3) The interlocking device related to the main motor works
  2, processing method:
   (1) Check the program and restart the car in the correct driving sequence.
   (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 cannot be turned on, and the motor cannot be turned on.
   (4) The induction current of the inverter has not been discharged, turn off the main power supply and wait for 5 minutes before starting.
   (5) Check whether the emergency button is reset.
Nine, the machine head is not smooth or blocked
  1. Reason:
   (1) A certain section of the heater does not work, and the material is poorly plasticized.
   (2) The operating temperature is set too low, or the molecular weight distribution of the plastic is wide and unstable.
   (3) There may be foreign objects that are not easy to melt.
  2, processing method:
   (1) Check the heater and replace if necessary.
   (2) Verify the set temperature of each section, negotiate with the technician if necessary, and increase the temperature set value.
   (3) Clean and check the extrusion system and the machine head.
10. The main starting current is too high
  1. Reason:
   (1) The heating time is insufficient and the torque is large.
   (2) A certain section of the heater does not work.
  2, processing method:
   (1) When driving, use a hand wheel, if it is not easy, extend the heating time or check whether the heaters of each section are working properly.
11. The main motor makes an abnormal sound:
  1. Reason:
   (1) The main motor bearing is damaged.
   (2) A certain thyristor in the thyristor rectifier circuit of the main motor is damaged.
  2, processing method:
   (1) Replace the main motor bearing.
   (2) Check the thyristor rectifier circuit, and replace the thyristor element if necessary.