How to Dry PLA Filament: Methods and Moisture Damage Explained

The Damage of Moisture in PLA Filament

1. Poor Print Quality: Moisture trapped in the filament can turn into steam when heated in the extruder, causing bubbles, stringing, oozing, or inconsistent extrusion. This leads to rough surfaces, layer adhesion issues, and weak prints.
2. Brittleness: Absorbed water can degrade PLA’s molecular structure over time, making the filament brittle and prone to snapping during printing.
3. Clogging and Jamming: Moisture-induced bubbles can cause irregular flow, leading to clogs in the nozzle and interruptions in the printing process.
4. Reduced Shelf Life: Prolonged exposure to humidity can permanently degrade the filament, rendering it unusable and wasting material.

Methods to Dry PLA Filament

1. Oven Drying

• Steps:
  1. Preheat the oven to a low temperature, ideally between 40°C and 50°C (104°F–122°F). PLA has a low glass transition temperature, so avoid exceeding 55°C to prevent softening or deforming the filament.
  2. Place the filament spool on a non-conductive surface (e.g., a ceramic plate or oven-safe tray) to ensure even heat distribution.
  3. Dry the filament for 4–6 hours, checking periodically to ensure it doesn’t overheat.
  4. Allow the filament to cool before use to avoid thermal shock.
• Precautions:
  • Use an oven thermometer to verify the temperature, as some ovens may have inaccurate settings.
  • Avoid using a microwave, as it can damage the filament or spool.
  • Ensure the oven is clean to prevent contamination of the filament.

2. Dedicated Filament Dryer

• Steps:
  1. Place the filament spool in the dryer.
  2. Set the temperature to 40°C–50°C for PLA.
  3. Dry for 3–6 hours, depending on the dryer’s specifications and the filament’s moisture level.
  4. Some dryers allow printing directly from the device, keeping the filament dry during use.
• Advantages:
  • Consistent and safe drying with minimal risk of overheating.
  • Convenient for frequent use and large spools.
  • Often doubles as a storage solution.
• Recommendation: Popular models include the SUNLU Filament Dryer or PrintDry, which are affordable and reliable.

3. Food Dehydrator

• Steps:
  1. Place the filament spool in the dehydrator.
  2. Set the temperature to 40°C–50°C.
  3. Dry for 4–8 hours, depending on the dehydrator’s power and the filament’s condition.
  4. Check the filament periodically to avoid over-drying.
• Advantages:
  • Affordable and widely available.
  • Gentle airflow ensures even drying.
  • Suitable for multiple spools at once.
• Tip: Choose a dehydrator with adjustable temperature settings for better control.

4. Desiccant in a Sealed Container

• Steps:
  1. Place the filament spool in an airtight container or vacuum-sealed bag.
  2. Add a generous amount of silica gel packets or another desiccant (e.g., molecular sieves).
  3. Seal the container and leave it for 24–48 hours.
  4. Check the filament for signs of dryness (e.g., no sizzling during printing).
• Limitations:
  • Best for mildly damp filament or as a preventive measure.
  • Slower than heat-based methods.
  • Desiccants need periodic replacement or recharging.

5. DIY Solutions

• Example: Use a sealed container with a low-wattage incandescent bulb or a heated bed from a 3D printer set to 40°C–50°C.
• Steps:
  1. Place the filament in the setup, ensuring good airflow.
  2. Monitor the temperature closely to avoid overheating.
  3. Dry for 4–6 hours.
• Precautions:
  • Avoid open flames or high-heat sources.
  • Ensure proper ventilation to prevent heat buildup.

Best Practices to Keep PLA Filament Dry

1. Store in Airtight Containers: Use vacuum-sealed bags, plastic bins, or dry boxes with tight seals to store filament when not in use. Add silica gel packets or rechargeable desiccants to absorb any residual moisture.
2. Use Filament Dry Boxes During Printing: A dry box with a built-in desiccant and a feed tube allows you to print directly from a sealed environment, keeping the filament dry during long prints.
3. Control Storage Environment: Store filament in a cool, dry place with low humidity (ideally below 20% relative humidity). Avoid basements or areas prone to dampness.
4. Check Filament Before Printing: Test a small section of filament by extruding it manually. If you hear popping sounds or notice stringing, dry the filament before proceeding.
5. Recharge Desiccants Regularly: Silica gel and other desiccants lose effectiveness over time. Recharge them by heating in an oven (per manufacturer instructions) or replace them as needed.
6. Buy in Small Quantities: Purchase only the filament you need for short-term projects to minimize exposure to air over time.
7. Use Filament Clips: After opening a spool, secure the loose end with a filament clip to prevent unraveling and reduce air exposure.

Conclusion