APP – Purging (PET)

It is vital to purge your Filament Maker after each extrusion session, before stopping the flow of material.

1. What does “purging” mean ?

Purging means flushing a material out of the barrel of the Filament Maker, by pushing it out with a purging material.

2. Is it really necessary to purge the Filament Maker after each use ?

Yes, absolutely.

Even if you plan on processing PET several times in a row.

Only 3 materials can be left inside the machine during shutdown:

  • virgin PLA
  • HDPE
  • DevoClean MidTemp EZ

3. Why do I need to purge my Filament Maker ?

To avoid irreversible clogging of the barrel and degradation of the material.

After every session of extrusion, the Filament Maker must be purged thoroughly : all the PET must be flushed out of the barrel with a purging material.

Skipping the purging step can have terrible consequences for the equipment:

  • PET degrades. This starts as soon as the flow stops, knowing that the machine remains hot for 2h, and that plastics are degraded by heat. The plastic molecules start breaking, the structure changes, the plastic loses its properties and burns.
  • It will be very difficult to melt PET again. At the beginning of the next extrusion session, some of the PET might not come out of the barrel, clogging it partially. It is be impossible to achieve good results again until the barrel is clean.

4. What purging material can I use ?

The best choice is Devoclean MidTemp EZ.

5. What settings do I use to purge ?

There are no purging presets.

Temperature :

Do not change them. All PET temperatures are compatible with Devoclean MidTemp EZ.

Screw speed :

You can use the two following methods:

  • High speed purging: 15RPM
  • Disco purging: randomly change the speed every minute to create turbulence in the flow

Duration and amount :

You must keep purging until you get a pure output of Devoclean MidTemp EZ. This usualy takes about 15min, 200g.

6. Want to know more ?

Please make sure you read our Full Guide and become an expert of purging and maintaining your Filament Maker in good condition.

It contains more information, pictures, instructions, examples…

If you still have questions, please feel free to ask us at It will be a pleasure helping you avoid problems.