Recycling PLA Filament: Properties, Sources, and Applications

7 min readSep 9, 2023

PLA has become one of the most common materials used for 3D printing filament in recent years. The popularity of PLA stems from it being a renewable and compostable material, made from natural sources like corn starch, tapioca roots, or sugar cane. As a thermoplastic, PLA can be extruded into filament and provides an excellent material for fused filament fabrication 3D printers.

However, with the rapid growth of 3D printing, more PLA filament is being used and discarded than ever before. This has led to an increasing focus on recycling PLA to reduce waste and the environmental footprint of 3D printing. Recycling PLA filament involves processing used filament back into reusable material. When done properly, recycled PLA can be extruded into new filament spools with properties near that of virgin PLA. Filament recycling presents opportunities to divert PLA from landfills and incineration.

Why Recycle PLA Filament?

Reduces plastic waste: Used PLA filament is often still perfectly usable material. Recycling stops tons of plastic from ending up in landfills or incinerators unnecessarily. This gives the material a second life.
Closes the manufacturing loop: By reprocessing used filament into fresh spools, the lifecycle loop of PLA is closed. Recycling cuts down on extracting and refining new resources.
Saves energy: Recycling existing PLA consumes less energy than producing brand new filament from scratch. It also generates less greenhouse gases.
Promotes sustainability: Recycling aligns with sustainability initiatives and environmental responsibility goals. It demonstrates a commitment to reducing waste.
Lowers costs: Once recycling systems are in place, remanufactured filament can cost less than brand new filament. This makes materials more affordable.
Maintains quality: Studies have shown recycled PLA can perform closely to virgin material in terms of tensile strength, viscosity, and print quality.
Drives innovation: Recycling processes and equipment continue to improve. This progress will uncover new techniques and applications for recycled filament.

Considering these advantages, recycling systems will likely play an important role as 3D printing expands worldwide. PLA is projected to continue dominating the hobbyist 3D printing materials market. Having the infrastructure to recycle used filament at scale will be essential to manage the waste streams of the future.

How to Recycle PLA Filament?

Recycling PLA filament involves multiple steps to clean, prepare, and re-extrude the used material back into fresh filament.

Reduces plastic waste: Used PLA filament is often still perfectly usable material. Recycling stops tons of plastic from ending up in landfills or incinerators unnecessarily. This gives the material a second life.
Closes the manufacturing loop: By reprocessing used filament into fresh spools, the lifecycle loop of PLA is closed. Recycling cuts down on extracting and refining new resources.
Saves energy: Recycling existing PLA consumes less energy than producing brand new filament from scratch. It also generates less greenhouse gases.
Promotes sustainability: Recycling aligns with sustainability initiatives and environmental responsibility goals. It demonstrates a commitment to reducing waste.
Lowers costs: Once recycling systems are in place, remanufactured filament can cost less than brand new filament. This makes materials more affordable.
Maintains quality: Studies have shown recycled PLA can perform closely to virgin material in terms of tensile strength, viscosity, and print quality.
Drives innovation: Recycling processes and equipment continue to improve. This progress will uncover new techniques and applications for recycled filament.

Challenges With PLA Filament Recycling

While technically feasible, recycling PLA filament does come with some inherent challenges.

Material degradation — PLA can degrade with excessive heat, moisture, and mechanical stress during printing. This can lower the quality after reprocessing.
Contamination — Filament spools can become contaminated with oils, adhesives, solvents, paints, and other residues. These contaminants must be removed.
Mixed plastics — It’s common for filament to contain small amounts of other plastics like ABS or PETG. Separating and sorting filaments is difficult.
Colors and additives — Recycled filament struggles to achieve color consistency due to blending. Other additives like impact modifiers are also hard to control.
Equipment costs — Industrial recycling setups require major capital investments into machinery like grinders, extruders, and pelletizers.
Process economics — The costs involved must be offset by the value of the reclaimed material. Transportation logistics also play a role.
Lack of standards — There are currently no industry standards for recycled 3D printer filament properties or processes. More data is needed on optimal methods.

While these challenges exist, continued research into PLA recycling will help address them over time as processes are refined. The potential environmental benefits make it a valuable issue to solve, even if 100% closed-loop recycling cannot be fully achieved yet.

At-Home Recycling Methods

For those looking to recycle a modest amount of PLA filament at home, several options exist.

Filament extruders — All-in-one tabletop units like the Filabot can grind, pelletize, and extrude filament from scrap material. While limited in throughput, these make small batch recycling accessible.
DIY plastic grinders — Armed with a heavy-duty plastic granulator or shredder, DIYers can grind filament into recyclable pellets. These can then be cleaned and re-extruded.
Microwave treatment — Heating PLA pellets in a microwave can partially revive thermal properties, allowing re-extrusion with compromised properties.
Direct hot pressing — Sandwiching ground filament between parchment paper and using a clothes iron or heat press can produce thin, flat sheets of recycled PLA.
FilaFiddle — This hand-powered tool can reprocess small amounts of scrap filament into a rough approximation of 3D printer filament by squeezing it through a nozzle.

While not producing commercial quality filament, these at-home methods allow for small-scale closed-loop use of scrap PLA with minimal investment. The recycled material works decently for non-critical prints.

Industrial Recycling Initiatives

For participating in commercial scale PLA recycling, consumers and businesses have several options available:

Filabot — This company offers both small extruder systems for personal use as well as large industrial grinders and pelletizers. They accept bulk PLA waste to recycle and sell recycled filament.

Refil — Based in Europe, Refil recycles used PLA and PETG into high quality reclaimed filament. They sell their own recycled filament brands called Refuel and Refilament.

Terracycle — In partnership with UPS and Staples, Terracycle provides recycling collection boxes to accumulate used PLA filament spools, bottles, packaging, and products. Terracycle recycles these materials into new products and grants rewards.

Filamentive — Based in the UK, Filamentive collects used filament from customers to recycle and remold into new filament that is sold back at discounted prices.

Printed Solid — This US-based filament company accepts used filaments by mail to recycle into Jessie filament. They provide bulk recycling services as well and partner with reclamation initiatives.

Ultimaker — The 3D printer manufacturer partners to recycle used Ultimaker spools into new filament. They offer 2kg recycling mailers available in the US and Europe to return used PLA.

Along with these programs, many 3D printing companies are starting recycling initiatives. Local 3D printing shops and hacker/makerspaces sometimes also accept filament waste to recycle internally.

These commercial recycling efforts demonstrate the increasing viability of reprocessing PLA into usable filament. As more programs launch and processing technology improves, recycling capacity stands to dramatically increase in coming years.

Tips for Optimizing PLA Recycling

For those interested in having PLA recycled — either internally or through a service — here are some tips for getting the best results.

Keep filament dry — Prevent moisture from compromising used filament. Store properly sealed with desiccants.
Avoid cross-contamination — Don’t mix different plastics together. Sort filaments by purity.
Clean spools thoroughly — Remove adhesives, grease, residues that can degrade reprocessed plastic.
Grind properly — Use appropriate equipment and settings to grind filament into uniform pellet sizes.
Adjust extruder settings — Recycled filament flows differently. Modify temps and speed compared to new filament.
Expect color variations — Remanufactured filament loses color consistency due to blending.
Perform test prints — Dial in optimal settings for the recycled filament before large prints.
Have realistic expectations — Recycled PLA filament works great for prototyping and non-critical components but may not match virgin quality.

Following these best practices helps improve the experience when working with recycled filament. Leveraging partnerships with professional recycling services can take more work off your plate as well.

The Future of PLA Recycling

As 3D printing continues its expansion, recycling systems will need to grow to manage the waste streams of PLA filament and printed parts. Developing better solutions should involve coordination across the industry between materials companies, 3D printer manufacturers, recycling processors and consumers.

More facilities dedicated specifically to 3D printer filament recycling are expected to open to meet demand as supply and awareness increases. Automated sorting technology and chemical processes will also continue improving to achieve higher recycled material purity. Integrating tracing systems can help optimize recycling logistics to lower costs and overhead.

Meanwhile PLA chemical recycling research aims to break the material back down at the molecular level, allowing full restoration to original properties. Biotech companies are also developing improved biodegradable and compostable polymers engineered for recyclability.

Greater adoption of recycled filament use will be driven by competitive pricing compared to virgin filament as capacities scale up. Parts manufacturers utilizing 3D printing are likely to integrate recycled materials to meet sustainability goals. Desktop 3D printer users will also reuse more of their scrap with at-home recycling tools.

In the coming years, a mature PLA recycling ecosystem has the potential to reduce the environmental impacts of 3D printing while enabling more innovation and progress. By transforming waste into resource, communities can help pave the way to a circular economy future for PLA filament and 3D printing as a whole.