Filament Drying and Moisture Control

Refer to the specific material information page for drying conditions and moisture sensitivity of AON3D-validated materials. For filament purchased elsewhere, refer to the manufacturer recommendations.

Moisture Content

Polymers adsorb moisture when exposed to humid environments. The adsorption rate is dependent on the environment’s relative humidity and temperature and the properties of the polymer itself. Some polymers do not need to be dried prior to printing, while others can quickly absorb moisture, must be dried prior to printing, and kept dry during printing. Moisture presence strongly impacts the aesthetics of the printed part and the layer adhesion. Most polymers degrade in the presence of moisture when exposed to high temperatures. Moisture content can also accelerate the crystallization rate of some polymers.

Moisture Removal

The drying process is driven by the environmental temperature and relative humidity. Convection helps the drying process by removing water molecules from the environment directly around the polymer filament. A forced convection oven is particularly helpful for this task. Consumer-grade polymers, such as ABS and PLA, can be dried at low temperatures. Performance-grade polymers, such as PEEK, PEKK, and ULTEM™ 9085, generally require temperatures above 100degC. Drying can be done at room temperature by keeping the filament in a very dry environment, such as a sealed box with desiccant, for a long time. While this method is valid, it requires a very long time. These conditions are more useful to keep the filament dry after a drying process in an oven.

Filament Drying Procedure

Place the spool in a dust-free filament dryer or convection oven to be dried before printing. Use the recommended temperature and time outlined in the information page for the material you are using. Ensure that the spool used to hold the filament is heat resistant to a temperature above the drying process. Respool the filament if necessary.

All material purchased from AON3D comes on a spool that is resistant to drying temperatures and will not need to be respooled.

After drying, it is recommended that a filament dryer system is used to maintain the dry state during the printing process. This must be installed close to the filament inlet port on the back of the printer.

Filament Storage

When the filament is not in use, it is important to store it in a cool, dry, and dust-free place. Use a sealed bag or box with a moisture absorbing desiccant pack to inhibit moisture adsorption. For filaments that are especially susceptible to moisture adsorption, the use of moisture grabbers in a sealed bag is not enough for total protection from moisture. With materials like ULTEM(TM) 9085 and Nylon, the drying procedure is always encouraged before printing.

Last modified: November 4, 2019