While working with many compounders in North America, it has come to my attention that the vents on an extruder is an after thought while purging. What is a vent on an extruder barrel?
These vents are holes in the barrel that allow gases to escape and not build up pressure during production. When one is ready to clean this type of an extruder with purge compounds, most people do not even think about the vent or cannot find the plug that came with the machine. Therefore, when the purge they are using does not work as advertised, they are disappointed with the failure and typically stop using them.
The answer is simple--plug the vents during your purge sequence.
This advice applied whether you are using mechanical purge compounds (these work well with pressure, shear and speed) or chemical purge compounds (which work by heat and containment of the gases). As you can see, if the vents are not plugged, you lose the pressure that helps clean the screw and barrel during the purge sequence.
Learn about the importance of implementing proper purging procedures by downloading this free industry guide.