Types of Purging Compound
Purging Compound comes in different types and formulations. Each has its own characteristics and benefits. Most popular types are:
Mechanical Purge: Cleans by increasing the shear in the barrel with simple physical adjustments of the machine.
Chemical Purge / Foaming Purge: Cleans using chemical reaction.
Liquid Purge: Typically surfactant.
Use a Suitable Purging Method
Mechanical Purge
Effective across a wide variety of applications.
- Use the machine’s power to do the work - Most mechanical purging compounds rely on shear force and differences in material viscosities to clean injection molding machines and extruders.
- Some mechanical purges also rely on material affinity – they are attracted to carbon and/or other plastic resins. They should not have affinity for metal.
- There are no chemical reactions.
- There is no soak time required.

Chemical Purge/Foaming Purge
Can be effective in areas of low pressure where mechanical purges are sometimes less effective.
- A chemical reaction occurs in the barrel and/or die when the purge makes contact with the plastic or carbon in the barrel.
- This reaction attempts to break the chemical bonds of the contaminant, aiding in removal.
- Require soak times of 5-30 minutes.
- Foaming agents are often added.
