PEEK is hygroscopic : it absorbs moisture. It must therefore be dried prior to extrusion.
Skipping that step can result in a filament full of bubbles, and overall degradation (discoloration, loss of properties, bad flow…).
1. How to dry PEEK
It is good to dry 2kg of material at once. This way, you will have enough dry material to experiment with the settings and hopefully spool some, all in one extrusion session. Drying takes time and, if you do not dry enough material to finish your experiment or your spool, you will not have the option to instantly dry more, once extrusion has started.
Of course, if you have already done the experimental research, it is still beneficial to dry a lot of material, so that you can spool as much as possible in one session.
- Place 2kg of PEEK in the hopper of the Airid
- Screw the hopper firmly onto the Airid
- Set the 150°C and 4h. These are generic PEEK drying settings for a hot air dryer. You might find different conditions on the Technical Datasheet of your PEEK.
2. If you have a moisture analyzer
You can set 150°C and 20min, to verify the effectiveness of the drying process.
The target moisture is often 0.05%wt.
If, after the drying process, the residual moisture content is higher than this threshold, then maybe new drying settings should be found.