General Questions and Answers

Question
Why should we use a commercial purging compound?

Answer
Antiquated methods such as flushing the machine with the next resin or using regrind are time-consuming, material-wasting, and just plain ineffective in removing color and carbon contamination.  A high-performance purging compound such as ASACLEAN is designed to not only facilitate color and material changeovers, but to clean the machine as well.


Question
Why should we use commercial purging compound when we have all this “free” regrind?

Answer
Regrind isn’t completely “free” – there are costs associated with using regrind.   Aside from the energy cost for grinding, the greater cost lies in the ineffectiveness of regrind to purge and clean a machine.   It is likely that a machine will have to be purged for a considerable amount of time with regrind, and then also purged several times subsequently during production.  Clearly this offers no savings over using an effective commercial purging compound such as ASACLEAN.


Question
Does purging compounds only work for cleaning injection molding machines?

Answer
Most of all purging compounds is also quite effective in cleaning extruders (profile, resin-compounding, cast sheet, cast film, blown film and blow-molding). Check with your purging compound supplier.


Question
Is that true that you use less material with a chemical purging compound compared to a mechanical type purging compound?

Answer
That’s not exactly true. The amount of purging compound required to clean a machine is based not only on the machine (barrel) size but also on the degree of contamination within the barrel. It may require a second or even a third purge to clean the machine if contamination is severe.


Question
How much purging compound do I need to purge out my previous resin?

Answer
It varies. Our rule of thumb:  for screw and barrel cleaning, usually 1-3 barrel capacities are recommended.  For very tough jobs, such as machines that haven’t been cleaned in a while, an additional 1-2 barrel capacity may be necessary. Check with your purging compound supplier for recommended usage.


Question
How long does it take to purge with purging compound?

Answer
Purge time is affected by several key factors such as machine size, condition of screw and barrel, resins being purged, etc.  Therefore it’s difficult to predict how long a purging application could take.  However, ASACLEAN for an example consistently reduces the amount of purge time required in comparison to most other purging methods.


Question
We use purging compound only when we need to purge out tough resins such as PC or Ultem. For everything else, we use regrind or virgin PP to purge because we think it’s cheaper than using a purging compound. However, we often find that regrind or PP doesn’t always do the job.  Any recommendations?

Answer
It is no surprise that the regrind or virgin PP resin are not sufficient to purge your machines. Materials such as PC and Ultem are not designed to purge and clean machines the way purging compound is. When using regrind or virgin resins to purge, they simply layer over any resins, color deposits or carbonized material within the barrel. In time, these layers become additional sources of contamination, making purging even more difficult. We recommend that purging compound should be used to purge all resins, whether they are considered “simple” or “difficult” to purge, so that the machine is thoroughly cleaned and that any build-up of contamination is prevented.

For specific questions about ASACLEAN purging compound, please visit our website’s Q&A

Or contact us 
Phone: 800-787-4348
Email: Sales@asaclean.com