The first step in cleaning the screw is to turn off the bubble film machine (air cushion film machine), that is, close the bottom of the hopper; then reduce the screw speed to 15-25r/min and keep this speed to the front end of the die. The melt flow stops flowing. The temperature of all heating zones of the barrel should be set at 200 °C. Once the barrel reaches this temperature, it begins to clean immediately. Depending on the extrusion process (the die may need to be removed to reduce the risk of excessive pressure on the front of the extruder), it must be done by one person during cleaning: the operator observes the screw speed and torque from the control panel while observing the squeeze Pressure is applied to ensure that system pressure is not too high. The screw speed should be kept within 20r/min throughout the process. In low pressure die applications, do not remove the die for cleaning. Immediately stop the mold and remove the die as the extrudate is completely converted from the process resin to the cleaning resin, and then restart the screw (with a rotation speed of 10 r/min) to allow the residual cleaning resin to flow out.