This is the most important step when working with PEEK. Because many different grades of PEEK exist, it is difficult to define one set of perfect settings for all of them.
What they all have in common, is that a single mistake in this step can result in the irreversible clogging of the Filament Maker.
Starting your first experiment with a good transition at the right temperature will allow you to customize the settings for your specific grade of PEEK.
1. Preparing the Filament Maker
The nozzle must be protected from cold air in order not to become clogged by solidified PEEK.
Before starting, you should make sure that :
- the magnetic plate is covering the whole around the nozzle
- the fans are pointing ‘downward’ (not horizontally, nor toward the nozzle). During this whole transition process, there is no need to apply some fan cooling.
2. Transition Devoclean MidTemp EZ –> Devoclean HighTemp
PEEK must be processed around 400°C. The best transition material to reach those temperatures is Devoclean HighTemp.
But neither PEEK nor Devoclean HighTemp can be left inside the Filament Maker during shutdown, so the barrel will be filled with another material when the experiment starts – probably Devoclean MidTemp EZ, HDPE, or PLA.
Here is the procedure :
- If anything else than Devoclean MidTemp EZ is inside the barrel, then you must purge it with Devoclean MidTemp EZ. There are no presets for this operation : the temperatures you choose must melt both the initial material, as well as Devoclean MidTemp EZ (180-320°C).
- PLA can be purged with Devoclean MidTemp EZ at 180°C
- HDPE can be purged anywhere between 180°C and 280°C
- Once the barrel is full of Devoclean MidTemp EZ, set all temperatures on 300°C (you can decrease the screw speed or even stop extruding during the heating period).
- When Devoclean MidTemp EZ is coming out at 300°C, transition to Devoclean HighTemp.
3. Transition Devoclean HighTemp –> PEEK
As long as Devoclean HighTemp (or PEEK) is inside the barrel, the flow of material must not stop.
- When pure Devoclean HighTemp comes out at 300°C, set :
- H4, H3, H2 : 400°C
- H1 : 410°C
- fancooling : 0%
- screw speed : 5RPM
- Make sure you wait long enough for H1 to be above 405°C (H3 and H2 should also be above 395°C, H4 above 385°C).
- Transition from Devoclean HighTemp to PEEK (only start feeding a small amount of PEEK, such as 100g)
- Be prepared to react and purge with Devoclean HighTemp again if anything goes wrong
The transition is complete when pure PEEK comes out (dark translucent brown without any white impurities).