APP – Drying

Hygroscopic thermoplastics absorb moisture. They 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…).

If the colorant is in powder (pure pigment) or masterbatch form, separate from the carrier polymer, then it does not need to be dried. The colorant will be mixed with the dry material after the drying step.

1. How to dry the material ?

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, during the extrusion step. 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 your material in the hopper of the Airid
  • Screw the hopper firmly onto the Airid
  • Set the drying temperature and time which correspond to your material (those can often be found on the Technical Datasheet of your material. If not, you can find typical drying conditions online, or ask our Materials Team)

2. If you have a moisture analyzer

You can set the same drying temperature in your moisture analyzer, for 20min.

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.