Rosahl MDL-3 Dehumidifier Membrane
Hygrometer/Thermometer
MDL-3 Filament Storage Box KitProduct Categories
Rosahl Membranes for Keeping 3D-Print Filament Dry
Full Range of Rosahl Dehumidifer Membranes
Accessories, Power Supplies, Measurement
Kits for 3D-Print Filament kits-3d-print-filament-dryboxes
Microcontroller Modules
CodeVIsionAVR Compiler
Knowledge Base
Frequetly Asked Questions
Technical Documentation
Product Description
Complete Kit
A full kit with the Rosahl membrane, VREG2 USB-C power supply module and assembly material is available as well:
The MDL-3 by Rosahl is a compact flat-membrane dehumidifier module for volumes of up to 0.5m³ (500l).
Operation Principle
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.
Storage of 3D-Print Filament Spools
With an applicaple air volume of 500 liters the Rosahl MDL-3 membrane is suitable for storage of single filament spools e.g., in a 50-80 litre "Kreher® Waterproof Storage Box" with space for ~15-20 spools (alternatively Ikea "Samla" box, which has to be sealed separately). With pre-dried filament spools (especially spools made of cardboard contain quite high moisture) a continous storage at approx. 15% rH and less is achievable. We made a 3D printable mounting frame for the M-3J1R membrane plus USB-C power supply module, see the further product images.
Find 3D-printable mounting covers on Printables or Makerworld.
Which Membrane Suits What Application?
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.
Power Supply
Rosahl dehumidifer membranes requires a 3V DC supply voltage and draws in continous operation i.e., when the moisture level in the volume stabilized to a low level, just around 0.1-2W power depending on membrane size.
Due to the membrane being intrinsically hygroscopic, it absorbs humidity if no supply voltage is present. This moisture needs to be discharged on startup and leads to a significantly higher inrush-current that the regular operating current. During startup the supply voltage shall still not drop below 2V, otherwise moisture discharge is not possible or significantly delayed. Suitable current supplies are fold-back current limiting sources, which regulate the output current further down than pure constant current sources and hence maintain a certain output voltage. We provide suitable USB-C voltage regulator modules with fold-back current limiting, which can be used stand-alone or mounted into our 3D-print mounting frame/covers.
VREG-2 USB-C Power Supply Module 3V/3A
Technical Parameters
| Applicable Volume | ~0.5m³ |
| Dehumidifying Performance | 4g/day |
| Supply Voltage | 2.9-3.3VDC |
| Power Consumption | 2W (20°C/60%rH) |
| Rated Current | 900mA (dep. of rH) |
| Inrush Current | 7A |
| Operating Temperature | -10°C - +50°C |
| Operating Humidity | <=90%RH |
| Connecting Type | Flat Plugs |
| Weight | 110g |
| Dimensions | 96x63x2.3 mm³ |
Further Information
- MDL-3 Product Specification
- Instruction Manual
- Our collection of 3D-printable mounting frames/covers on Printables or MakerWorld.
- Frequently asked questions
Scope of Delivery
The Rosahl MDL-3 dehumidifier comes as single unit without gasket.