Drying PLA Filament: Why It Matters and How to Do It Right

PLA is widely known for its ease of use, but like all 3D printing filaments, it is hygroscopic. This means it absorbs moisture from the environment, leading to issues such as poor surface quality, reduced strength, and popping noises during extrusion. For makers and professionals alike, drying PLA filament is a necessary maintenance step to ensure consistent, high-quality prints.

In this guide, you'll learn how to recognize when PLA has absorbed moisture, how to dry it safely, and how to store it effectively to avoid recurring problems. We'll also compare PLA to other popular filaments, highlight best practices, and offer tips specific to home and workshop environments.

How Moisture Affects PLA Filament

When PLA absorbs moisture, water molecules begin to break the polymer chains through hydrolysis. This weakens the structural integrity of the material and leads to printing failures. You'll notice the effects in several key areas:

• Reduced interlayer bonding, resulting in fragile prints
• Increased stringing and oozing during printing
• Dull or rough surfaces
• Popping and cracking noises during extrusion

Best Methods for Drying PLA Filament

1. Filament Dryers

A purpose-built filament dryer is the best tool for the job. These devices are engineered to operate within the correct temperature range for specific filaments. For PLA, the ideal range is 40–50°C. Most dryers allow you to set the exact time and temperature, and many offer a feeding function to print directly from the drying chamber.

Drying typically takes 4 to 6 hours. This is sufficient to remove most of the absorbed moisture, even in humid environments. Some dryers include humidity sensors, giving you better control over the process.

2. Conventional Oven

A standard household oven can be used, but caution is necessary. Set it to 40–45°C and dry the filament for 4 to 6 hours. Since ovens aren't always precise, use a separate thermometer to verify the temperature.

3. Food Dehydrators

Food dehydrators offer a good balance between temperature control and ease of use. They are more stable than ovens and less likely to damage PLA. Choose a dehydrator that can reach at least 40°C and remove inner trays to accommodate your spool.

Run the dehydrator for about 6 hours. The circular shape of most dehydrators makes them suitable for spools without modification. This method is energy-efficient and safe for extended use.

Storing PLA Filament to Prevent Moisture Absorption

After drying, store PLA filament immediately in a controlled environment. Effective storage methods include:

• Airtight plastic bins with silica gel or other desiccants
• Vacuum-sealed bags with moisture indicators
• Dedicated dry boxes with electronic humidity control

Can You Overdry PLA?

Yes, overdrying PLA is possible. When exposed to temperatures above 50°C for long periods, PLA can become brittle and lose its elasticity. Stick to the recommended 40–50°C range and limit drying sessions to 6 hours.

How Often Should You Dry PLA Filament?

There’s no fixed rule, but monitor your filament for signs of moisture damage:

• Print defects like rough textures or stringing
• Weak or brittle final prints
• Nozzle popping during extrusion

Drying PLA vs. Other Filaments

Practical Considerations for Home Users

Not every maker has access to a filament dryer. If you're using an oven or dehydrator, perform a small test dry first with a partially used spool. You can also build a DIY dry box with airtight storage bins and reusable desiccant packs.

3D printing in coastal areas or during rainy seasons often requires more frequent drying. Consider rotating multiple spools, so you're always using one while another is drying or in storage.