Rosahl Electric Dehumidifer Membranes for 3D-Print Filament Dryboxes

Operation

Rosahl dehumidifiers are based on a solid-state polymer membrane. When supplied with a 3V DC voltage, moisture on one side is being decomposed into Hydrogen ions and Oxygen, the Hydrogen ions pass the membrane and recombine with air Oxygen to moisture again on the other side and get discharged.
The Rosahl dehumidifiers are compact, work fully mainenance-free and the power consumption is very low.

Storage of 3D-Print Filament Spools

Rosahl dehumidifiers are suitable for dry storage of filament spools of various materials for 3D printing. We inspected several storage boxes with regards to their suitability (sealing, capacitiy, etc.) and selected several Rosahl dehumidifiers for our product range, which turned out well suited. The usually required deccicant (Silica gel), which has to be regenerated periodically, is no longer needed.

We achieved a final humidity in the selected combinations of dehumidifiers and storage boxes of max. 15% rH in continous operation. Filament spools should be properly dried before (in e.g., filament dryers or oven), otherwise it can take considerably longer to reach the final jumidity.

To simplify mounting the Rosahl dehumidifiers into the storage boxes we designed suitable 3d-printable frames/covers. Those are linked on the product pages and can be downloaded for free on Printables.com.

Which Membrane Suits What Storage Box Size?

The following table reflects our own applications with different membranes and usage scenarios in our climate zone with max. 65-70%RH and could serve as a guide for membrane selection.

(1) This is the specified applicable volume by the manufacturer. For 3D print filament storage at low humidity levels around 15%, we recommend to oversize the membrane at least by a factor of 5 or 6. Achievable end-humidity depends on various factors like box sealing, temperatur, outside humidity level. In regions with high air humidity it might be beneficial to oversize the membrane more.
(2) The Bambu Lab AMS comes with some manufacturing variations and can be less properly sealed as stated. Given this, also an M-1J1R or M-2J1R can give decent results but it is recommended to carefully check for potential leakages and proper/tight gasket sealing before chosing a membrane size. It might hence be beneficial to oversize the membrane more. If in doubt, contact us prior to selecting/ordering.