Product AM Expo 2023

Sustainable 3D Printing: Create and Use Recycled Filament

Dive into the world of sustainable 3D printing, where discarded plastic finds new life as meticulously crafted filament. This transformative journey has led us through the intricacies of plastic recycling, filament extrusion, and now, the art of 3D printing with recycled materials.


Embarking on the journey towards sustainable 3D printing has brought us to a pivotal moment: putting to use the filament we have meticulously extruded from recycled plastic waste. This journey has been a multifaceted one, encompassing the study of recyclable plastics, the mastery of shredding techniques, the refinement of filament extrusion, and now, an exploration into the intricacies of 3D printing with recycled filament. We have learnt the importance of filament diameter, the impact of moisture absorption, the nuances of temperature settings, and much more. As we delve into the world of 3D printing, our recycled filament, created with precision and care, takes center stage.

Understanding Filament

Before we dive deeper into the process, it is essential to understand what filament is. Filament is the raw material used in FDM (Fused Deposition Modeling) 3D printers. FDM is the most common 3D printing method used for creating physical objects from digital models. The filament used in this process is typically made of thermoplastic materials, such as PLA (Polylactic Acid) and ABS (Acrylonitrile Butadiene Styrene), or PETG (Polyethylene Terephthalate Glycol). It is also important to understand the characteristics of different thermoplastics. PLA, for instance, is biodegradable and made from renewable resources like corn starch or sugar cane. However, ABS is petroleum-based, stronger, and more flexible but emits fumes when melted. PETG is a variant of PET, it is glycol-modified for extra durability and is considered food-safe, but it can be sensitive to moisture. Knowing these properties will help you decide what type of plastic to recycle and how to handle them during the 3D printing process.

Filament comes in spools of various colors and thicknesses, typically with a diameter of 1.75mm or 2.85mm. During the 3D printing process, the filament is heated and extruded through a nozzle onto a build plate, layer by layer, to create a 3D object. The build plate and the nozzle move in a coordinated fashion, guided by the printer’s software, to create the desired shape.

PLA colored filament and some 3d prints


Recycling Plastics into Filament

Not all plastics are suitable for filament recycling. Plastics with a clear recycling symbol (usually with a number) are better candidates. For example, PET, commonly found in plastic bottles; PLA, often used in disposable tableware; and ABS, frequently used in hard plastic items, can be recycled into filament. It’s important to research and identify the types of plastics that can be effectively recycled in your setup.

Remarkably, this process allows us to give a second life to a variety of everyday items. Imagine transforming discarded plastic bottles, old production plastics, or even failed 3D prints into brand-new objects. This not only contributes to a reduction in waste but also enables creativity and innovation.

At 3devo, we have developed our own Plastic Shredder and Filament Maker that streamlines this process, transforming plastic waste into valuable recyclable filament. These innovative tools empower individuals and businesses to contribute to environmental sustainability by recycling and reusing plastics that would otherwise end up in landfills.

Different plastics have different melting temperatures and characteristics. PLA, for example, typically extrudes at temperatures between 180-220°C, whereas ABS extrudes at higher temperatures, usually between 220-250°C. Therefore, it is important to sort the plastics by type before shredding and extruding them into filament. The filament maker from 3devo has precision temperature control to ensure the plastics are melted at the correct temperature, preventing degradation of the material.

The diameter of the filament is also crucial for successful 3D printing. Most 3D printers use filament with a diameter of 1.75mm or 2.85mm. The 3devo Filament Maker allows you to precisely control the diameter of the filament during the extrusion process, ensuring it is consistent throughout the spool. A variation in diameter, even as small as 0.05mm, can lead to under-extrusion or over-extrusion, affecting the print quality.

Filament Extruders


Getting Started: The Testing Phase

As you prepare to 3D print something with recycled filament, we advise you to start by testing a small 3D print first. Extruding filament from recycled plastics may yield slightly different properties compared to conventional filament. By conducting a trial run, you can begin to understand how the recycled filament behaves, ensuring you're well-prepared for 3D printing your desired objects.

It is advisable to use a caliper to measure the filament diameter at multiple points along its length to ensure consistency. Also, perform a bend test by bending the filament at a 90-degree angle. A good-quality filament will bend without breaking. If the filament snaps, it may indicate that the material is too brittle or that it was extruded at an incorrect temperature. Here are some other aspects of this you need to understand: 

Embracing the Experimentation Phase

Just as filament extrusion involves a degree of experimentation, so does 3D printing. It's important to approach this phase with an open mind and patience. Remember, the path to perfection is often paved with trial and error. Don't be disheartened if your initial prints don't meet your expectations. Embrace the learning process and relish the joy of creating, even among the occasional challenges.

Understanding Filament Texture

Before you dive into 3D printing, take a moment to assess your filament's texture. Consistency is key; your filament should exhibit an even and round texture throughout its length. Inconsistencies in texture can lead to printing issues. If you notice any irregularities, consider revisiting the filament extrusion process. Our material expert, Timo, has shared insights into achieving optimal filament extrusion in a helpful video guide that you can check out at the end of this blog.

Filament thickness irregularities


Temperature and Printing Settings

Achieving successful 3D prints heavily relies on accurate temperature and printing settings. Different plastic materials respond uniquely to heat; finding the optimal balance is crucial. Setting the temperature too high can lead to uneven melting, resulting in subpar print quality. Leverage online resources to identify the appropriate settings for your chosen recycled filament.

The optimal printing temperature may vary slightly depending on the 3D printer and the specific characteristics of the recycled filament. For example, the optimal printing temperature for commercial PLA filament is usually between 190-220°C. Still, recycled PLA may require a slightly higher or lower temperature due to impurities or changes in material properties during recycling. It is advisable to start with a temperature in the middle of the range and then adjust it in 5°C increments until the optimal temperature is found.

The layer height and print speed also play a crucial role in the success of a 3D print. A lower layer height will result in a smoother finish but will increase the print time. A higher print speed can lead to under-extrusion and poor layer adhesion. Therefore, finding the right balance between layer height, print speed, and temperature for the specific recycled filament you are using is very important. Also, note that the optimal settings for recycled filament may vary from those of commercial filament, as the recycled filament may contain impurities or have slightly different properties.

Transform Plastic Waste into Your Own Recycled Filament

Contribute to environmental sustainability, reduce waste, and unleash your creativity by transforming plastic waste into your own recycled filament.

Discover Our Filament MakerFilament makers


Filament Storage

Once the filament is made, it is essential to store it properly to maintain its quality. The filament is hygroscopic, meaning it absorbs moisture from the air. This is especially true for PLA and PETG. Absorbed moisture can lead to poor print quality and can cause the filament to become brittle. Therefore, storing the filament in a dry, cool place, preferably in a sealed bag with desiccant, is advisable. Before printing, it is also advisable to dry the filament in a filament dryer or an oven at a low temperature (e.g., 50°C for PLA) for several hours to remove any absorbed moisture.

3D printing space with filament storage


Begin 3D printing

Armed with a test print, a solid understanding of filament texture, an experimental mindset, and calibrated temperature settings, you're now ready to embark on your 3D printing adventure. Remember, the 3D printing community is a supportive and collaborative space. Sharing your creations on social media is gratifying and provides an opportunity to connect with fellow enthusiasts. Don't forget to tag us – we're genuinely excited to witness your innovative endeavors.

Selecting Your First Project

Choosing your first project is an exciting moment. Start with something simple and functional, as this will allow you to focus on the printing process rather than the intricacies of a complex design. When choosing your first project, consider the properties of the recycled filament. Some materials are more brittle and may not be suitable for functional parts that need to withstand stress. Others may have a lower melting point and may not be suitable for objects that will be exposed to high temperatures. Use your knowledge of the material properties to select a suitable project for your recycled filament.

Monitoring the Print

It's important to closely monitor the print, especially during the initial layers, as this will set the foundation for the rest of the print. Make necessary adjustments if you observe any warping or adhesion issues. Most 3D printers come with software that allows you to make real-time adjustments to settings such as temperature and print speed.

In addition to monitoring the initial layers, it is also important to monitor the entire print. Some common printing issues to look out for include warping, where the corners of the print lift off the build plate; stringing, where thin strands of filament form between parts of the print; and layer separation, where the layers of the print do not adequately adhere to each other. Each of these issues can be addressed by adjusting the printer settings, such as the bed temperature, print speed, or retraction settings.

3D printing with Ultimaker


Post-Printing Process

Once the printing is complete, carefully remove the print from the build plate. Some prints may require additional post-processing, such as sanding, painting, or assembling multiple parts. Take your time during this stage to ensure a high-quality finish.

Reflect and Improve

After completing your first print, take some time to reflect on the process. What went well? What could be improved? Make notes of any adjustments that need to be made to the printer settings or the filament extrusion process. Each print is a learning opportunity; you will gain more confidence and expertise with each print.

In addition to reflecting on the printer settings and filament extrusion process, it is also important to consider the source material. Did the recycled filament contain too many impurities? Was it sufficiently dry before extrusion? Did the mixed plastic types affect the filament properties? These considerations will help you refine your recycling and 3D printing process for future projects.

Remember, practice makes perfect. The more you print, the more you will learn about the nuances of your 3D printer and the characteristics of the recycled filament. And most importantly, have fun! 3D printing is not only a rewarding and environmentally friendly hobby but also a gateway to endless creativity and innovation.


In conclusion, the journey towards sustainable 3D printing is one filled with challenges and learning opportunities. From understanding the types of plastics that can be recycled to shredding, extruding, and finally printing with the recycled filament, each step is crucial and requires attention to detail. We have learned the importance of testing and experimentation, the need for careful monitoring of the print, and the value of post-processing and reflection. As we move forward, let us remember the importance of this work. By recycling plastics and turning them into valuable filament, we are not only reducing waste but also contributing to a more sustainable and innovative future. Let us continue experimenting, learning, and sharing our knowledge with the community. Together, we can make a difference.