How to store material

Proper material storage is key to achieving consistent, high-quality print results.

Filaments, particularly opened spools, should be protected from potentially harmful environmental factors to preserve quality. This includes temperature, light (UV), and humidity. Materials that are not stored correctly may become brittle, break more easily, or change color, all of which affect the final part properties.

Note: The tips in this article may apply generally to all 3D printing materials, but the content is specifically about UltiMaker 2.85 mm materials. For information about Method materials, please visit this section. For third-party materials, always follow the manufacturer's recommendations.

Optimal storage conditions

Proper storage conditions help preserve filament quality, print reliability, and shelf life. To keep your filaments in prime condition, store them:

• in a re-sealable bag
• out of direct sunlight
• in a dry and cool location

The most important environmental factors are temperature, light (UV exposure), and humidity. See more details about each of these factors below.

Temperature

Store UltiMaker filaments in a cool, stable environment, within the following temperature ranges:

• PLA, Tough PLA, PETG, PET CF, PPS CF, CPE, CPE+, PC, Nylon, Nylon CF Slide, PP, TPU 95A, Breakaway: –20 °C to +30 °C
• ABS: 15 °C to 25 °C
• PVA: 10 °C to 30 °C

Avoid prolonged exposure to temperatures outside these ranges. Cool to normal room temperatures (15–20 °C) are advised for storage to prevent negative effects from temperature swings.

Note: Temperature affects the physical stability of thermoplastic materials over time. Excessive heat can accelerate material aging, while very low temperatures can make some materials stiffer and more prone to snapping during handling.

Light / UV exposure

Ultraviolet (UV) light can cause photo-degradation of polymers over time. This process breaks down polymer chains, which can permanently affect mechanical properties. To prevent UV from affecting material quality, always store spools out of direct sunlight.

Tip: Use opaque packaging or closed storage systems whenever possible

Humidity

Many filaments absorb moisture from the air. During printing, absorbed moisture can vaporize in the nozzle, negatively affecting extrusion consistency, surface quality, and mechanical properties.

• Store filament in a dry environment, preferably in a re-sealable bag with desiccant or a humidity-controlled storage system.
• For moisture-sensitive materials (PVA, Nylon, Nylon CF Slide, TPU 95A), keep relative humidity below 50% to prevent moisture uptake.
• In practice, most UltiMaker materials are optimally stored at approximately 10–30% relative humidity.

Tip: Extremely low humidity levels (for example, close to 0–1%) are not required to prevent moisture absorption and do not provide significant additional benefit compared to typical dry-storage conditions.

Note: Brief exposure to ambient air (for example, while transferring a spool from storage to a printer or Material Station) does not significantly affect filament quality, provided the material is returned to a dry environment promptly. For conditions during printing, please see the recommended ambient operating temperatures in the product's data sheet or user manual.

Shelf life recommendations

Following optimal storage conditions, we recommend a maximum shelf life of 1 year for moisture-sensitive materials (e.g. PVA, Nylon, Nylon CF Slide, PLA, TPU 95A) and a maximum shelf life of 2 years for more chemically inert materials (e.g. PP, PC).

Note: Shelf life assumes that the materials are stored under the recommended temperature and humidity conditions and protected from light and environmental exposure.

Identifying poorly stored filament

Incorrectly stored materials can collect dust and absorb moisture, leading to extrusion problems and reduced print quality. Moisture absorption can also cause popping sounds during printing. While nearly all filaments are affected by humidity to some extent, certain materials are much more susceptible than others.

PVA and Nylon are particularly prone to moisture absorption and can degrade more quickly than other materials. Transparent Nylon may appear cloudy or milky, while black Nylon tends to lose its glossy finish.

PVA exposed to moisture will become soft and pliable and may even become sticky. It is possible to dry PVA and other moisture-sensitive materials following the procedure described in this article: How to dry UltiMaker PVA. PVA that is too dry may become rigid, which could also cause problems while printing.

To check the quality of normally rigid materials, try to bend the filament. If the filament snaps or splinters easily, it is too brittle for use and should be replaced. In some cases, only the outer part of the filament is affected. In this case, it may be sufficient to remove the first one or two meters from the spool and continue using the rest.

Note: Brittleness can have multiple causes, including material aging, formulation, and environmental exposure; humidity is one of several factors that can influence handling and print performance.

Overview of negative effects

Using the Material Station

UltiMaker S series printers (except the S3) are compatible with the Material Station. The Factor 4 features an integrated Material Station. Inside the Material Station (with the door closed), the filament is automatically kept at the recommended humidity.

Note that the Material Station does not actively dry the filament, neither the S series nor the Factor 4 version. If the filament has already absorbed excessive moisture, dry the filament before installing the spool in the Material Station.

Avoid placing the Material Station (Pro Bundle or Factor 4) in direct sunlight to prevent negative effects from UV exposure or too high temperatures.

Tip: Learn more about using the Material Station here: How does the Material Station work?

Drying filament

To properly recover filament that has absorbed moisture, it should be dried at elevated temperatures. For material-specific recommendations, more information can be found on this page: How to dry Ultimaker materials

Tip: For several materials, including TPU 95A, Nylon CF Slide, and PET CF, it is recommended to pre-dry the material after unboxing for the best results.