Filament Drying and Moisture Control

AON3D recommends the use of the Filament Dry Storage and Feed System to help control the level of moisture often found in polymers.

Refer to the Materials Guide for drying conditions and moisture sensitivity of AON3D-approved polymers. For filament purchased elsewhere, refer to the manufacturer recommendations.

Moisture Content

  • Polymers absorb moisture when exposed to humid environments. The absorption rate is dependent on the level of relative humidity found in the print environment, and the temperature, and the properties, of the polymer filament itself.
  • Some polymers do not need to be dried before a print is started, while others can quickly absorb moisture and must be dried before, and kept dry, during printing.
  • The presence of moisture 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 process to remove the moisture is driven by the environmental temperature and/or relative humidity.
  • A forced-air convection oven can greatly help control the environmental temperature and/or relative humidity. A forced-air convection oven removes the water molecules from the environment that surrounds the polymer filament.
  • 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 need temperatures above 100°C (212°F).
  • To remove the moisture from the polymer filament, it can be stored in a sealed box with silica desiccant in a very dry environment for a long period of time. While this method is effective, this procedure needs a long period of time for it to be done successfully. This method is more of a preventive measure as it is mostly used to keep the polymer filament dry after a drying process in a forced-air convection oven.

Filament Drying Procedure

There are two options to dry polymer filaments:

Use the recommended temperature and time outlined in the Materials Guide page for the material that is used. Make sure that the spool that is used to hold the filament is heat-resistant to a temperature above the drying process. Re-spool the filament, if necessary.

All polymer materials purchased from AON3D use heat-resistant spools and will not need to be re-spooled.

After the filament has been successfully dried, it is recommended that the AON3D Filament Dry Storage and Feed System is used to keep the polymer filament dry when in the machine is in operation.

Filament Storage

When the filament is not in use, it is important that it be stored in a cool, dry, and clean place. Use a sealed bag or box with silica desiccant pack(s) to prevent moisture absorption.

For filaments that are especially susceptible to moisture absorption, the use of moisture grabbers in a sealed bag is not enough for total protection from moisture. With materials like ULTEM™ 9085 and Nylon, the procedure to dry these materials is always encouraged before a print is started.

Last modified: April 9, 2024