What Are the Common Malfunctions of the Double Screw Extruder?

Double screw extruder refers to the use of the self-adhesiveness of the dispersed solid powder and liquid mixture with solid phase as the main component, and through forced means to make the basic particles of solid powder stick to each other and enlarge, forming a certain shape and uniform particle cluster.


Unstable discharge of double screw extruder


Reason analysis


Some segments of the heater do not work, and the material is not well plasticized. The operating temperature is set too low, or the molecular weight distribution of the material is wide and the performance is unstable. There may be difficult-to-melt foreign materials, such as small pieces of metal and sand, which enter the extruder and block the die.


Solution


Check the heater and replace it if necessary. Verify the set temperature for each segment and consult with the process technician to increase the temperature setting value if necessary. Clean and check the extrusion system and die of the double screw extruder.


Common faults of double screw extruders


The main motor cannot start


  • Reasons: Wrong driving procedure. Problems with the main motor thread or whether the fuse wire is burned.

  • Handling methods: Check the procedure and restart the driving process in the correct order. Check the main motor circuit. Check whether the lubricating oil pump is started and the state of the interlocking device related to the main motor. The induction electricity of the frequency converter is not completely released, shut down the main power supply and wait for 5 minutes before restarting. Check whether the emergency button is reset.


Abnormal sound from the main motor


  • Reasons: Damaged main motor bearings. Damage to a thyristor in the main motor controllable rectification circuit.

  • Handling methods: Replace the main motor bearings. Check the controllable rectification circuit of the main motor and replace the thyristor components if necessary.


Unstable main motor current


Reasons: Uneven feeding, damaged or poorly lubricated main motor bearings, malfunctioning of certain heater segments without heating, improper screw adjustment pads or incorrect phase, component interference.


Handling methods: Check the feeding machine and eliminate faults. Repair the main motor and replace bearings if necessary. Check whether each heater is working properly and replace the heater if necessary. Check the adjustment pads, pull out the screw of the double screw extruder and check whether the screw is experiencing interference.


Excessive temperature rise of main motor bearing


  • Reasons: Poor lubrication of the bearings. Serious bearing wear.

  • Handling methods: Check and add lubricant. Check the motor bearings and replace them if necessary.

News