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Why Does PLA Filament get Brittle

  • 5 min read

Why Does PLA Filament Get Brittle? Causes and Maintenance Tips

Among the various materials used for 3D printing, PLA (Polylactic Acid) filament stands out as one of the most popular choices among makers and creators. Its ease of use and affordability have made it a go-to option for a wide range of projects. However, there's a common issue that many 3D printing enthusiasts encounter: PLA filament becoming brittle over time. In this comprehensive guide, we will explore the reasons behind this phenomenon and provide valuable tips for maintaining your PLA filaments in prime condition. So, if you've ever wondered, "Why does PLA filament get brittle?" - read on to discover the answers and how to prevent it.

What is a PLA filament for 3D printing?

PLA (Polylactic Acid) filament is one of the most popular and widely used materials in the world of 3D printing. It's a thermoplastic derived from renewable resources like cornstarch or sugarcane. PLA is known for its ease of use, affordability, and versatility, making it an excellent choice for both beginners and experienced 3D printing enthusiasts.


The filament distinguishes itself with its low melting point. This characteristic is a double-edged sword; while it enables smooth and effortless printing, it also introduces unique challenges. The low melting point is part of PLA's molecular structure, which, despite facilitating easy printing and a glossy finish, has a downside. This structure renders PLA susceptible to brittleness over time, a phenomenon that raises significant concerns.

Why do the PLA filaments get brittle?

The propensity for brittleness in PLA is a multifaceted issue. It stems from various factors, ranging from environmental interactions to the intrinsic qualities of the material. Let's examine each of these factors in more detail.

Moisture Absorption

One of the primary reasons for a brittle PLA filament is moisture absorption. PLA is hygroscopic, meaning it naturally absorbs moisture from the air. This moisture absorption causes the filament to become less flexible and more prone to cracking. When water molecules interact with PLA, they break down the polymer chains, leading to a weaker structure. This is particularly problematic in humid environments or if the filament is not stored properly.

Excessive Heat Exposure

PLA's low melting point, while beneficial for ease of printing, also makes it sensitive to high temperatures. Prolonged exposure to heat can lead to a gradual deterioration of the filament's quality. The heat can cause the PLA to soften and then harden in a more brittle state, especially when this cycle is repeated over time.


Over time, PLA filaments can degrade due to natural aging processes. This degradation is accelerated by exposure to UV light, which can break down the molecular bonds in the PLA, leading to a loss of elasticity and increased brittleness. Even when not in use, PLA filaments can be affected by ambient UV light, which is why proper storage is critical.
In this context, opting for high-quality PLA filaments can help mitigate these challenges. At AnkerMake, we are committed to providing premium PLA filaments that lead to more durable and reliable 3D prints. Designed for high-speed printing, our PLA 3D printer filaments have undergone over 12 months of intensive printing tests in our Speed Lab, proving their resilience and durability. With a minimal shrinkage rate of just 0.33%, our filaments not only ensure precise printing but also show enhanced resistance to the common causes of brittleness.

Tips for Caring and Maintaining the PLA Filaments

Having understood the factors contributing to their brittleness, it becomes evident that proper care and maintenance are essential. Here are some essential tips to help you keep your PLA filaments in optimal condition:

Store the Filaments Properly

Use airtight containers to prevent moisture absorption, which can lead to filament brittleness. Include desiccants like silica gel packets to absorb any residual moisture. Store the containers in a consistently cool and dry environment.

Avoid High Temperatures

Since PLA is sensitive to heat, it's important to store it in a place where it isn't exposed to high temperatures. Ideal storage temperatures range between 10 – 30 °C (50 – 86 °F). Keep the filament away from heat sources like heaters and ovens and avoid placing it in areas prone to temperature spikes, such as attics, garages, or near windows that receive direct sunlight.

Protect them from the UV

Prolonged exposure to UV light can degrade PLA filaments, affecting their color and strength. To prevent this, store the filaments in a dark place or use containers that block UV rays. If direct sunlight is unavoidable in your storage area, consider using UV-protective window films or curtains to minimize exposure.

Inspect and Replace Regularly

Regular inspection is vital for maintaining the quality of PLA filaments. Check for signs of brittleness, discoloration, or other damage before each use. If degradation signs are evident, replace the filament to ensure consistent printing quality. Using compromised filament can lead to poor print quality and printer jams. Keep track of how long a spool has been open. PLA filaments can degrade over time, so older spools should be checked more frequently.

Optimize PLA Filament Usage with Advanced 3D Printers

After exploring the intricacies of PLA filament brittleness and discussing essential care and maintenance practices, it's crucial to consider the role of the 3D printer in optimizing these efforts. At AnkerMake, we offer cutting-edge 3D printers, namely the AnkerMake M5 and M5C, designed to not only optimize filament usage but also to elevate the overall printing quality and efficiency.
Our AnkerMake M5 3D Printer stands as a benchmark in efficient 3D printing. It boasts an impressive speed of up to 500 mm/s, drastically cutting down print times. Precision is key in our design, with a detailed accuracy of 0.1 mm, ensuring optimal use of PLA filament for crisp, intricate prints. The integrated AI camera for real-time monitoring and a sophisticated 7×7 auto-leveling system further contribute to reducing filament wastage, guaranteeing precision in every layer.
Our AnkerMake M5C 3D Printer elevates the printing experience with user-friendly features like multi-device control with our AnkerMake app and customizable one-click operations. It matches the M5's speed and enhances filament efficiency with a high extrusion flow rate of 35 mm³/s. The robust all-metal hotend is designed for smooth and consistent filament extrusion, reducing the risk of jams and ensuring efficient filament usage.


With the AnkerMake M5 and M5C, you're not just choosing advanced 3D printers; you're opting for a synergy of speed, precision, and efficiency, tailored for the best PLA filament printing experience.


Throughout this blog post, we've delved into the factors behind the question, 'why does PLA filament get brittle', including moisture absorption, exposure to excessive heat, and aging. To ensure the durability and excellence of your 3D prints, it's imperative to adhere to the care and maintenance tips we've outlined. By storing your filaments correctly, safeguarding them from high temperatures and UV exposure, and conducting regular inspections and replacements, you can consistently achieve impressive results in your 3D printing projects with PLA filaments.


Can PLA filament be revitalized if it has become brittle due to moisture absorption?

Yes, PLA filament can often be revitalized. Here's how to fix brittle PLA filament:


Bake it: If needed, bake the filament in an oven at a low temperature (around 50°C or 120°F) for a few hours, monitoring closely.
Use a filament dryer: Invest in a filament dryer specially designed for effective moisture removal.

Is there a way to determine if PLA filament has become brittle without printing with it?

Yes, you can determine if PLA filament is brittle by:


Visual Check: Look for cracks or roughness on the surface.
Bend Test: Gently bend it; if it snaps easily, it's brittle.
Tug Test: If it breaks with slight tugging, it's likely brittle.

Can exposure to UV radiation lead to PLA filament brittleness?

Yes, PLA is susceptible to degradation when exposed to UV light from sources like sunlight or certain artificial lights. UV radiation breaks down the molecular bonds in PLA, causing it to become brittle and lose its structural integrity.