In daily production, plastic pipe extrusion line equipment will inevitably have a variety of failures, affecting the normal operation of the production line. Below, I’ll introduce the causes of common failures of plastic pipe extrusion lines and treatment methods.
Plastic pipe extrusion line Extruder section common faults
1. Vacuum automatic suction machine suction force reduction
Rationale：
1) Filter clogging.
2) Air leakage exists due to poor sealing.
Methods of handling：
1) Clean the strainer inside the hopper and the filter on the suction machine.
2) There is air leakage in the pipeline from the suction machine to the small hopper, find out the location of the air leakage and seal it again. The small hopper below the slanting mouth of the jam is caused by air leakage, adjust the flap limit screws to make the flap open at a greater angle to fully discharge the material to prevent jamming and air leakage.
2. The extruder can not start
Rationale：
1) Temperature has not been reached and is in a protected state.
2) The extruder system is in an alarm state.
3) Circuit fault or electrical component damage.
Methods of handling：
1) Check the temperature to see if the temperature in a certain zone has not reached the set temperature.
2) Click on the alarm screen to check whether there is an alarm. Solve the corresponding alarm according to the alarm code before starting.
3) Find the starting circuit part according to the circuit drawing and check whether there is an open circuit or poor contact, etc., and also check whether there is damage to the electrical components.
3. The extruder starting current is too high
Rationale：
1) The parameters are incorrect.
2) The temperature is low and the heating time is insufficient.
3) The raw materials at the feed port agglomerate and cause blockage.
Methods of handling：
1) The rated parameters of the equipment may be mistakenly changed. Adjust the correct parameter values according to the main motor and reduction ratio.
2) The temperature setting is too low and the heating time is insufficient. Increase the setting temperature to increase the heating time.
3) Empty the hopper and clean out the agglomerated materials at the discharge port.
4. Extruder makes abnormal noise
Rationale：
1) The motor bearing is damaged.
2) Reducer gear damage.
3) Foreign matter enters the barrel screw.
Methods of handling：
1) Replace the main motor bearings and perform regular maintenance.
2) Replace the reducer gear.
3) Pull out the screw to remove foreign matter. If the barrel screw is damaged, replace it in time.
5. The extruder discharge is unstable
Rationale：
1）The screw has not been replaced for a long time and the screw is worn.
2) The main engine speed is unstable.
Methods of handling：
1) Replace the barrel screw.
2) You can use the speed monitoring parameters on the host screen or the inverter to determine whether the speed is stable. If the analog voltage of the given speed is disturbed, find the interference source and eliminate it.
Plastic pipe extrusion line Vacuum tank part common faults
1. The vacuum pump and water pump cannot be started
Rationale：
1) The start button is damaged.
2) The circuit breaker in the control cabinet trips.
3) The vacuum pump or water pump is damaged.
4) Control line failure.
Methods of handling：
1) Replace the start button.
2) Open the control cabinet to check whether the air switch has tripped, reopen the air switch, and check the cause of the trip to prevent secondary damage.
3) Replace the vacuum pump and water pump.
4) Find the starting circuit according to the circuit diagram and check whether there is any open circuit or poor contact.
2. Automatic water inlet and outlet failure
Rationale：
1) The solenoid valve is damaged.
2) There is no compressed air supply.
3) Liquid level failure.
4) The angle seat valve is damaged or stuck.
Methods of handling：
1) If the solenoid valve can light up and close normally and the air pressure is normal, it means that the solenoid valve is damaged and needs to be replaced.
2) Access to compressed air > 0.6Mpa.
3) If the liquid level is disturbed by foreign matter such as scale after long-term use, clean the ditch in time and replace the liquid level controller if necessary.
4) The angle seat valve is opened by compressed air and connected to compressed air of >0.6Mpa. At the same time, the angle seat valve is disassembled and lubricating oil is added.
3. Vacuum open water spray volume reduced
Rationale：
1) Air leakage.
2) The water pump selection is too small or the vacuum pump is too large.
Methods of handling：
1) There must be air leakage in the vacuum box, which is usually caused by air leakage at the connection between the water pump and the water tank hose.
2) Choose the pump power reasonably.
Haul-off unit prat common faults
1. Haul-off uni cannot start
Rationale：
1) Servo drive parameter error
2) The alarm on the host alarm screen has not been cleared.
3) Line failure.
4) Electrical components are damaged.
Methods of handling：
1) The manufacturer’s electrical drawings usually have a correct parameter list. Enter the correct parameters according to the parameter list.
2) Clear the Haul-off uni alarm on the host alarm screen.
3）Is the host PLC output terminal I1.2 working? If I1.2 does not light up, there may be a problem with the PLC port. When I1.2 lights up, check whether the corresponding intermediate relay KA01 is working. If both are working, check whether the two wires I1.2 and 24V from the host to the traction machine are broken.
4) Replace damaged electrical components.
2. The haul-off unit can be started, but the haul-off unit does not turn.
Rationale：
1) Line failure.
2) The analog module is damaged.
3) Parameter fault.
Methods of handling：
1) Is there a 0-10V voltage on line 509 510 on the host module? If the host module has a 0-10V voltage, check the line 509 510 from the vacuum box to the traction machine in turn. If there is a circuit breaker, 509 510 is connected in reverse.
2) Change the analog module.
3) The manufacturer’s electrical drawings usually have a correct parameter list. Enter the correct parameters according to the parameter list.
Cutting machine part common faults
1. The cutting machine and the turning rack do not move.
Rationale：
1) Wrong material pushing method selection.
2) The time setting is too long.
3) The solenoid valve is damaged or has no air pressure.
Methods of handling：
1) Whether the pushing method is selected correctly, the fixed length limit cutting must use time.
2) Reduce the time setting.
3) Replace the solenoid valve and connect to >0.6Mpa compressed air.
2. Pipe cutting does not break
Rationale：
1) The cutting time is set too short.
2) The cutting knife scale is not placed accurately.
3) During cutting, the oil pressure valve is opened too small and the pressure is insufficient.
Methods of handling：
1) Increase cutting feed time and parameter setting.
2) Adjust the position of the cutting feed slider to correspond to the scale of the ruler.
3) Rotate the oil valve counterclockwise to increase the oil supply and pressure.
3. Auto cut not working
Rationale：
1) The encoder is damaged.
2) There is an alarm.
3) Incorrect parameter settings.
Methods of handling：
1) Replace the encoder. The encoder wiring is I0.0.I0.1, 24V, 0V.
2) Check if there is an alarm on the display, check the limit switch and eliminate the alarm.
3) Are the parameters of the text set correctly? The general unit is mm, and the conventional lengths are 6000mm, 9000mm, and 12000mm.
At JWELL Machinery, we specialize in producing high-quality plastic extrusion equipment designed to improve the reliability and efficiency of extrusion lines. Whether you are facing specific technical problems or looking to upgrade your equipment, our team can help you. Please contact us to learn how our advanced extrusion solutions can enhance your production process. Please contact us for detailed consultation and customized support. Let us drive your success in the plastics industry together!
