What are the respective advantages and disadvantages of the different types of purging compounds?

Abrasive purging compounds provide fast and reasonably effective cleaning, but they can also damage screws and cylinders/barrels. It is dangerous to use them in hot runner systems, through screen packs or melt pumps. Abrasive purging compounds are more difficult to evacuate from the machine, creating greater potential for longer-term damage as well as for production-run contamination and scrap creation. Chemical purging compounds are safer for the equipment and may also be processed through screen packs and melt pumps. They are universally usable in hot runner systems and can be injected in cavities when a purge compound with an appropriately suitable MFI is selected. Because they are safer for the equipment, they are also more suitable for using as part of a preventative maintenance program as opposed to only as a “problem-solving product.” More recently, hybrid purging compounds, combining the efficiency of a mechanical cleaning with the thoroughness of chemical cleaning, have been developed. Purging concentrates allow for easier storage, but hold the potential risk of incorrect dosage and feeding issues.