New to purging compounds? Or an experienced hand but recognize that you could use a refresher? Here are some best practices and troubleshooting tips beyond the set of basic purging procedures.
It is important to keep in mind that there is a number of purging compound categories in which products fit, based upon their method of cleaning action. For example, there are mechanical-type purging compounds, and chemical-type purging compounds, to name the two most common. While some of the following tips can be used universally across purging compound categories, the following tips are particularly recommended for mechanical-type purging compounds.
For years my company, which supplies the Asaclean brand of purging compound, has recommended three basic, yet crucial tips for purging injection molding machinery:
1) Use maximum safe screw speed while purging (and while displacing the purging compound)
2) Use maximum safe backpressure while purging (and while displacing the purging compound)
3) Keep the screw completely forward while purging
Using high screw speed and backpressure ensure greater agitation and "turbulence" so that the purging compound's scrubbing / cleaning capabilities are maximized. Keeping the screw completely forward ensures that the agitation of the screw (along with the purging compound) is focused...