PrintDry Filament Dryer
Many of us have experienced that a new filament prints great in the beginning, but regularly fails after few months in storage, especially materials like nylon that tend to absorb allot of moisture form the air. When printing in a heated nozzle the moisture will turn into steam and try to evaporate. When this happens, the filament will make a popping/cracking/hissing sound and the 3D prints will have rough/grainy surface finish with much reduced physical properties (less tensile and impact strength).
Most 3D printing filaments (ABS, PLA, PETT, PC and Nylon) are hygroscopic materials, which have a strong affinity for moisture. When being exposed, these filaments readily absorb moisture from the air. The migration of moisture into the filament occurs over time and will eventually slow and stop when the moisture content reaches a state of equilibrium with that of the surrounding air. At the equilibrium point, the moisture content in the filament will be evenly distributed throughout the entire filament's interior. Actually the water molecules inside the filament are attached to the polymer molecule chains, forming a strong inter-molecular bond, as shown in figures below. This bond is what makes drying the filament difficult.
The PrintDry filament dryer offers an easy and effective way to "pull" the moisture out of filaments.
In addition, with a special turn-table design it can feed the filament into a 3D printer for printing while drying. This makes it an in-line filament dryer.
The desiccant packs coming inside a filament package cannot reduce the water content inside filaments since they are not strong enough to break the inter-molecular bond and "pull" the moisture out of the filament. Instead, the desiccant packs are used mainly to prevent water content in a filament from going up other than reducing it. On the other hand, if exposed the desiccant itself will become saturated with moisture and lose its much-needed moisture absorbing capacity.
The PrintDry filament dryer is designed to actively reduce the water content in a filament based on the following basic principles:
- Drying Temperature: As the temperature is increased, the molecules inside a filament move more vigorously and this weakens/breaks the moisture/polymer inter-molecular bonds to let water molecules travel more freely through the filament towards the filament surface. Different filament needs different drying temperature.
- Moisture Concentration Differential: Surrounding a moist filament with dry (low dew point) air, will encourage water molecules inside a filament to migrate more readily to the surface and eventually being carried away by air.
- Drying Time: It takes time for moisture to get into the filament and it also take time to pull them out. Filaments do not dry instantly. First, it takes time for the heat to penetrate/distribute throughout the filament interior, especially those deeply buried in the spool. Second, it takes time for the newly freed water molecules to defuse to the surface of the filament.
- Air Flow: Airflow carries heat to the filament and also carries water molecules away.
The PrintDry filament dryer has been independently tested by Intertek and TUV to meet applicable product safety standards in both North America and Europe. It is ETL and TUV Rheinland GS listed.