When it comes to 3D printing, PLA (Polylactic Acid) is often the go-to material for many enthusiasts and professionals alike. Its popularity stems from its ease of use, affordability, and biodegradability, making it an ideal choice for a wide range of applications. However, when the conversation shifts to outdoor 3D printing applications, the suitability of PLA comes into question. This blog post delves into whether PLA is safe for outdoor use, its limitations, and how to mitigate its shortcomings.

Understanding PLA and Its Popularity

PLA is a thermoplastic derived from renewable resources like cornstarch or sugarcane, which makes it a more environmentally friendly option compared to petroleum-based plastics. Its ease of use, especially in desktop 3D printers, has made it a staple in the 3D printing community. PLA prints at relatively low temperatures, typically between 190°C and 220°C, and doesn't require a heated bed, making it accessible to beginners and experienced users alike.

The UV Resistance of PLA

One of the most significant concerns with using PLA for outdoor applications is its UV resistance. PLA is not 100% UV resistant, meaning that when exposed to sunlight over time, the material will start to degrade. The UV rays from the sun can cause the PLA to become brittle, leading to cracking, warping, or even complete structural failure in extreme cases.

Studies have shown that while PLA can withstand outdoor conditions for a period, its longevity is limited. Depending on the environmental factors such as sunlight exposure, temperature fluctuations, and humidity, PLA may last a few years outdoors. However, it's essential to note that these results vary widely based on specific conditions. In climates with high UV radiation or extreme weather, the degradation process can be significantly accelerated.

Protecting PLA from UV Degradation

Despite its limitations, there are strategies to extend the lifespan of PLA parts used outdoors. One of the most effective methods is to apply a UV-resistant coating or paint to the printed parts. This additional layer acts as a barrier, protecting the PLA from direct sunlight and reducing the impact of UV exposure.

Painting Your PLA Parts:
A UV-resistant paint not only enhances the longevity of your PLA prints but also offers an opportunity to customize the aesthetic of your project. When choosing a paint, look for those specifically designed for outdoor use, as they often contain additives that block or absorb UV rays. Before painting, ensure that your PLA part is clean and free of any oils or dust, as this will help the paint adhere better.

Sealing and Priming:
Another option is to use a UV-resistant sealant or primer before painting. These products can provide an additional layer of protection, further safeguarding your PLA parts from the elements. While this method adds extra steps to your post-processing workflow, it can be well worth the effort, particularly for projects intended for long-term outdoor use.

Considering Alternatives: ASA for Outdoor Durability

If your project requires a material that can withstand outdoor conditions without the need for additional protective measures, ASA (Acrylonitrile Styrene Acrylate) is a viable alternative to PLA. ASA is a thermoplastic developed specifically for outdoor applications, offering superior UV stability and weather resistance compared to PLA.

Benefits of ASA:
ASA retains the ease of printing similar to PLA but with enhanced mechanical properties that make it suitable for outdoor use. It is resistant to UV radiation, meaning it won't degrade as quickly when exposed to sunlight. Additionally, ASA is more resistant to heat and chemicals, making it a more durable option for projects that need to endure harsh environmental conditions.

Printing with ASA:
Printing with ASA is slightly more complex than PLA, as it typically requires higher temperatures and a heated bed to prevent warping. However, for those looking to create long-lasting outdoor parts, the investment in learning to print with ASA is well justified.

Conclusion: Choosing the Right Material for Your Outdoor Projects

In summary, while PLA can be used for outdoor applications, it is not the most durable option when exposed to UV light over extended periods. If you choose to use PLA for an outdoor project, taking the time to apply a UV-resistant paint or sealant can significantly extend the life of your prints. However, for those seeking a more robust solution, materials like ASA offer the UV stability and weather resistance needed for long-term outdoor use.

Choosing the right material for your 3D printing project ultimately depends on the specific requirements of the application. Understanding the limitations of PLA and exploring alternative materials like ASA will ensure that your outdoor projects stand the test of time.