Plastic extrusion problems and solutions – 10 major causes of failure

Plastic extrusion problems and solutions Introduction.

Plastic extrusion machine is a common plastic machinery equipment. In the process of daily operation of the extruder, various failures will inevitably occur in the extruder, which will affect the normal production of plastic machinery. The failure is analyzed in detail.

1. The host current is unstable

Production reason:

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.

4) The screw adjustment pad is wrong, or the phase is wrong, and the components interfere. 

Approach:

1) Check the feeder and troubleshoot.

2) Overhaul the main motor and replace the bearing if necessary.

3) Check whether the heaters work normally, and replace the heaters if necessary.

4) Check the adjustment pad and pull out the screw to check whether the screw has interference.

2. The main motor cannot be started

cause:

1) The driving procedure is wrong.

2) There is a problem with the main motor thread, whether the fuse is burnt.

3) The interlocking device related to the main motor works.

Approach:

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 does not turn on, and the motor cannot turn on:

1) Check if the emergency button is reset.

2) If the induction power of the inverter has not been discharged, turn off the main power supply and wait for 5 minutes before restarting. 

3. The machine head is not smooth or blocked

cause:

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 easily melted. 

Approach:

1) Check the heater and replace if necessary.

2) Verify the set temperature of each section, and negotiate with the craftsman if necessary to increase the temperature set value.

3) Clean and check the extrusion system and the machine head.

4. The main electric starting current is too high

cause:

1) Insufficient heating time and large torque.

2) A certain section of the heater does not work. 

Approach:

1) Use the hand crank when driving. If it is not easy, extend the heating time or check whether the heaters of each section are working normally.

5. The main motor makes an abnormal sound

cause:

1) The main motor bearing is damaged.

2) A certain thyristor in the thyristor rectifier circuit of the main motor is damaged. 

Approach:

1) Replace the main motor bearing.

2) Check the thyristor rectifier circuit, and replace the thyristor element if necessary. 

6. The temperature rise of the main motor bearing is too high

cause:

1) Poor lubrication of bearings.

2) The bearing is seriously worn. 

Approach:   

1) Check and add lubricant. Check motor bearings and replace if necessary. 

7. The pressure of the machine head is unstable

cause:

1) The speed of the main motor is uneven.

2) The rotation speed of the feeding motor is uneven, and the feeding amount fluctuates. 

Approach:

1) Check the main motor control system and bearings.

2) Check the feeding system motor and control system.

8. The lubricating oil pressure is low

cause:

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.

Approach:

1) Check and adjust the lubricating oil system pressure regulating valve.

2) Check the oil pump and oil suction pipe. 

9. The automatic screen changing device is slow or not working

cause:

1) Air or oil pressure is low.

2) Air leakage (or oil leakage) of the cylinder (or hydraulic station)

Approach:

1) Check the power system of the screen changing device.

2) Check the sealing of the air cylinder or hydraulic cylinder.

10. The safety pin or safety key is cut off

cause:

1) Excessive torque of extrusion system

2) The connection between the main motor and the input bearing is not concentric 

The above is the introduction of plastic extrusion problems and solutions. In order to ensure production safety, problems arising from plastic extrusion machine need to be solved in time.