How to clean the screws inside the twin-screw extruder after use?

The first step is to close the charging plate, i.e. close the charging opening at the bottom of the hopper. Then reduce the screw speed to 15-25 r/min and maintain this speed until the melt stream at the front of the die stops flowing. All heating zones of the barrel should be set at 200°C. As soon as the barrel reaches this temperature, start cleaning.

The first step is to close the charging plate, i.e. close the charging opening at the bottom of the hopper. Then reduce the screw speed to 15-25 r/min and maintain this speed until the melt stream at the front of the die stops flowing. All heating zones of the barrel should be set at 200°C. As soon as the barrel reaches this temperature, start cleaning.

Depending on the extrusion process (it may be necessary to remove the die head to reduce the risk of excessive pressure on the front end of the extruder), cleaning must be done by one person. The operator observes the screw speed and torque from the control panel while observing the extruder to ensure that the system pressure does not become too high.

The screw speed should be kept within 20r/min throughout the process. In the applications of low pressure die head , do not remove the die head for cleaning first. As soon as the extrudate is completely converted from process resin to cleaning resin, stop the machine and remove the die head, then restart the screw (within 10r/min) to allow the residual cleaning resin to flow out.

Dismantling

1. Manually add transition material from the feeding port until the color of the extruded material strip is the same as the granule of cleaning material, then stop feeding, empty the material, and stop the screw rotation of the twin-screw extruder.

2. Open the extruder die head and start cleaning.

3. Turn the screw of the extruder and take out the orifice plate, drain the residual transition material in the barrel and clean the orifice plate.

4. Stop rotating,then pull out the screw, using automatic screw cleaning machine. It takes 10 to 20 minutes to clean a screw, automate operations, 360-degree clean without dead angle. Put back the screw, add new material to flush the residual cleaning material in the barrel, then stop the screw rotation.

5. Install the orifice plate and die head to the extruder to complete the cleaning operation of the twin-screw extruder.