Purging your pellet extruder on a regular basis is an important maintenance step in order to keep your screw and barrel clean.
Introduction: The Importance Of Purging Your Pellet Extruder
Besides basic maintenance, purging a pellet extruder is a crucial step in maintaining the quality of thermoplastic materials produced through extrusion. The process of purging removes residual material and fibers from the pellet extruder, ensuring that the next batch of material will not be contaminated. Contaminated material can lead to defects in the final product, leading to faulty prints. In addition, purging can help lower the downtime of your pellet extruder by preventing excessive wear and tear of all the internal components.
Types of Purging Methods:
Although there are more types of purging, we mostly focus on two main strategies:
1. Mechanical Purging: Mechanical purging involves removing residual material from the pellet extruder using a scraper or cleaning tool. This method is useful for removing hard or stubborn material that may be difficult to remove using other methods. This can be useful for all the external components like nozzles.
2. Chemical Purging: Chemical purging involves the use of a purging compound that is designed to break down and remove residual material from the pellet extruder. Chemical purging is effective for removing color and carbon buildup, as well as other types of contamination. We have different types of purging compounds available, depending on the temperature range. Ask your Sales Engineer for the right compound.
Best Practices for Purging Pellet Extruders:
To ensure that purging is effective and efficient, it is essential to follow best practices for purging pellet extruders. The following are some best practices for purging pellet extruders:
1. Regular purging: Regular purging can help prevent contamination and reduce downtime. Scheduling purging based on the type of material being processed and the frequency of production can help ensure that the extruder remains clean and free of contamination. We suggest to purge your pellet extruder at least once a week.
2. Use the correct amount of purging compound: Using the correct amount of purging compound is essential for effective purging. Using too little purging compound can result in incomplete purging. Typically, when the purging compound comes out of the pellet extruder as a transparent substance, it should be enough. As long as it is not transparent, there is still residue inside the pellet extruder.
3. Soaking: Let the pellet extruder ‘soak’ for a few minutes with the purging compound. This means that the barrel of the pellet extruder must be full of purging compound, and you keep it for a few minutes. Just leave the heaters on and don’t purge. This will give the chemicals some time to break down the residual material on the inside of the extruder.
4. Speed variation: When purging the pellet extruder, also play around with the pellet extruder speed. Go higher and lower in screw RPM. Even after purging for a while, this can help to get some last bits and pieces out of it.
Conclusion, cleaning pellet extruders:
Purging is a critical step in maintaining the quality of your pellet extruder, and thus the quality of the prints. Purging removes residual material from the pellet extruder, ensuring that the next print will not be contaminated. By following best practices for purging pellet extruders, such as regular purging and following the right steps, you will expand the lifetime of your pellet extruder.