Introduction & Story

I started PETmachine back in 2018 as a simple but powerful idea: what if we could turn used plastic bottles into 3D printer filament? It began as my personal mission to tackle plastic waste in the 3D printing world while making filament more accessible. The spark came when I realized how many PET bottles end up as trash and how expensive filament can be in underserved communities. I imagined empowering makers to literally print with recycled waste – a vision that set PETmachine in motion. This journey even led me to compile our work into a scientific article titled “PETmachine: Turning Plastic Bottles into 3D Printing Filament”, which I was proud to present at a technology conference in Japan in 2020 (Science Article attached below).

The project truly took shape when I connected with Kevin, a STEM teacher in Kenya. In his community, plastic bottles pile up as trash while 3D printing filament is scarce and costly. I sent Kevin a PETmachine prototype to test, and it quickly became the centerpiece of his classroom. Students could turn discarded soda bottles into usable filament – literally transforming trash into educational treasure. Seeing PETmachine churning out filament in a Kenyan school (filament later used to 3D print tool handles and prosthetic aids) proved that this idea could have real-world impact. It reinforced my core mission: empower communities to create what they need from the resources around them. I also drew inspiration from makers in Sierra Leone, imagining how recycled-filament could be paired with low-cost prosthetics or crutches – mobility aids produced from the very plastic littering the streets. Early field tests and conversations made it clear that PETmachine wasn’t just a gadget; it could be a game-changer for sustainability and accessibility in 3D printing.

Today, over 2000 PETmachines are in use globally and have received outstanding reviews from makers, educators, and institutions. One notable example is the PEThouse project in Turkey, where PETmachine plays a role in producing components for sustainable cat shelters made from recycled materials.

Motivation

• Problem: Millions of plastic bottles are discarded every day, polluting our environment, and in many parts of the world 3D printer filament is expensive or hard to get. This means tons of PET plastic waste on one hand, and a lack of affordable printing material on the other. For example, in rural Kenya lack of filament limits the ability to print spare parts or assistive devices – while plastic waste continues to accumulate unchecked. And this is not just the case in developing countries—many developed nations still don’t have effective, deposit-oriented recycling programs. PETmachine gives you the chance to take plastic recycling into your own hands, literally creating your personal recycling factory on your desk.
• Consequence: Valuable plastic ends up in landfills or oceans, while students, makers, and engineers in low-resource areas can’t fully leverage 3D printing due to the high cost of filament. There’s a growing demand for sustainable 3D printing materials that isn’t being met.
• Goal: Create a low-cost, easy-to-build machine that enables anyone to recycle PET bottles into usable 3D filament. By doing so, we tackle two challenges at once: reducing plastic waste and supplying cheap filament for education, prototyping, and humanitarian projects. PETmachine’s mission is to make recycling practical and local – bringing filament production into community makerspaces, schools, and homes. This eco-friendly, closed-loopsystem reduces environmental impact while meeting the demand for sustainable making. On top of that, PETmachine was designed to also deliver the same joy and satisfaction as assembling a DIY kit – like building with LEGO blocks. It’s a perfect weekend project to learn, create, and help the planet at the same time.

Design Overview

PETmachine® transforms everyday plastic bottles into high-quality 3D printing filament. I designed it to be compact and user-friendly – built mostly from 3D printed parts plus simple off-the-shelf components. The process is straightforward: cut a PET bottle into a continuous strip, feed it into the machine’s heated extruder, and out comes a 1.75 mm filament strand neatly wound onto a spool. By enabling makers to produce their own filament from waste, PETmachine helps save money on filament and reduces plastic pollution at the same time.

Cost & Materials: I offer three options (available in my STORE):

• Essential Parts Kit: €145 (includes all non-printed parts and hardware).
• Advanced Parts Kit: €295 (includes all printed parts).
• Fully Assembled Machine: €350.

PETmachine’s frame and structure require around 1.4 kg of filament, which should ideally be flame-retardant (e.g. PETG FR V0). A standard desktop 3D printer with a 180×180 mm build area is enough to print all the components. For parts near the heater, ABS/PC-ABS V0 filament should be used – use materials with flame retardants only. The design is modular – sections bolt together and individual parts can be reprinted or upgraded.

Power Consumption & Output:

• Power draw is around 45 W.
• 8–35 minutes per bottle, depending on strip quality and settings.
• Each bottle gives 8–35 meters of filament.

	Grams of filament per Bottle	Meters of filament per Bottle	Speed
1.5 Litter Bottle	14-18 Grams	6 Meters	1 Meter per Minute
2.5 Litter Bottle	24-30 Grams	10 Meters	1 Meter per Minute
5 Litter Bottle	45-60 Grams	20 Meters	1 Meter per Minute
10 Litter Bottle	90-110 Grams	35 Meters	1 Meter per Minute

• In one hour, you can produce around 30–60 meters, or about 60–120 grams of filament depending on bottle type.
• Electricity costs (example):
  • EU avg: 0.30 €/kWh → ~1.35 cents/hour
  • US avg: 0.15 $/kWh → ~0.675 cents/hour
  • Kenya avg: 0.22 $/kWh → ~0.99 cents/hour

• Creating 1kg of filament cost just 6-13 cents in electricity!

These numbers make PETmachine one of the most affordable ways to produce filament, and perfect for small-scale, eco-conscious makers.

Assembly Instructions

Building a PETmachine is meant to be doable for makers and educators, even those with only moderate experience. All the required 3D printed files (STLs) and an extensive assembly manual are provided with the project. The instructions are written in beginner-friendly language, with step-by-step guidance and diagrams.

Note: To prepare bottles and successfully process them, you’ll also need a pump or compressor, a kettle or heat gun, scissors, and a knife.

Assembly Steps: Building PETmachine basically involves a few main steps:

1. 3D Print the Parts: First, print all the parts in the recommended materials. (Tip: our documentation includes detailed print settings for each part. For example, larger structural parts benefit from 4–8 wall perimeters for strength, while small gear parts may need higher infill density.)
   Ready-to-print GCODEs for Bambu Lab printers are available, which makes the process even faster and more beginner-friendly.
   Be sure to use filaments with flame-retardant additives.
2. Mechanical Assembly: Mount the gearmotor and hotend onto the printed frame, and bolt on the sub-assemblies (the bottle cutter module, feeder, guide rollers, spool holders, etc.) to the main frame. The design is modular, so you typically assemble it in sections – e.g. attach the cutting module to the extruder body with a few screws, snap the winder spool brackets into place, and so on. The major modules come together with basic fasteners in a straightforward way.
3. Electronics & Wiring: Install the power supply, temperature controller, motor driver, and cooling fan inside the enclosure. All connections are plug-in: no soldering needed, as components use screw terminals or pre-crimped connector wires. For safety, all mains-voltage wiring is enclosed and clearly labeled. (It’s recommended that an adult or someone with basic electrical knowledge supervises this step, since the machine does connect to 110–230 V AC mains power for the heater supply.) The assembly manual provides step-by-step wiring instructions to make this process as simple as possible.
4. Calibration & Usage: Once built, using PETmachine is straightforward. Begin by cutting a PET bottle into a strip (or use the included auto-cutter module to do this inline). Insert one end of the plastic bottle strip into the machine’s feeder, then turn on the heater and set it to around 210 °C. Once it reaches temperature, start the motor to begin extrusion. The bottle will be sliced into a ribbon (if using the auto-cutter) and drawn into the hotend.
   The plastic is plasticized (not molten!) and shaped into filament as it’s pulled through the nozzle. It passes through the cooling fan stream and onto the take-up spool.
   You can adjust the motor speed (via the controller knob) to fine-tune the filament thickness as it extrudes. In practice, after a bit of calibration we’ve been able to produce very consistent 1.75 mm filament. When a bottle is fully processed, you simply feed in a new bottle strip and continue, or swap out the spool if it’s full.

The first build usually takes 3–4 hours to assemble, and perhaps another hour to dial in optimal settings (temperature and feed speed) for your particular bottle plastic. We include tips in the guide on selecting bottles (transparent PET bottles work best) and even how to dry the filament if needed, since PET can absorb moisture. Overall, the goal is that anyone can build and operate PETmachine with a bit of patience – turning what was once seen as “trash” into a valuable resource!

Testing & Results

We rigorously tested PETmachine with a variety of bottle types and sizes to ensure it works reliably. During development, countless plastic bottles were “sacrificed” in our workshop (in a very eco-friendly way!) to tune the device. Here are some key results from our testing and from early users:

• Filament Quality: The PET filament produced by PETmachine has been successfully used in standard FDM 3D printers. We conducted test prints to verify strength and consistency. For example, using filament made from a 1.5 L Coca-Cola bottle, we 3D printed a small flower vase – the print was smooth and watertight. From a green Lipton iced-tea bottle, we made a Hulk figurine as a fun detail test, which came out great in terms of surface finish and accuracy. We even printed a larger plant pot from recycled bottle filament to test structural strength – it’s currently holding soil and a live plant with no issues. These experiments showed that bottle filament can be viable for both decorative and functional prints, as long as your 3D printer is properly equipped. (Notably, printing filament made from PET bottles requires an all-metal hotend capable of ~270 °C and a good extruder drive. We recommend a dual-drive extruder to handle the slightly stiffer filament, and many users report excellent results with Prusa or other direct-drive setups.)
• Throughput: PETmachine produces filament at roughly 1 meter per minute (about 60 m per hour). This is slower than big industrial extruders, but it’s sufficient for personal use and classroom demos. Converting a typical 1.5–2 L bottle yields around 6–12 m of filament in 10 minutes. In one stress test, we ran the machine continuously to process about 10 bottles in a row – it churned out over 100 m of filament in that single session without any motor overheating or nozzle clogs. The built-in PID controller keeps the temperature steady within a few degrees, which is crucial for consistent filament diameter throughout the run. So while you won’t be mass-producing spools overnight, PETmachine’s output is perfectly fine for hobby and educational needs.
• User Feedback: Early adopters around the world have built PETmachines and shared their experiences, and the feedback has been overwhelmingly positive. Many makers were surprised at how easy the assembly turned out to be, noting that the instructions were clear and all parts fit together on the first try. Users have praised the design for being well thought-out and beginner-friendly – one reviewer even mentioned “I’m enjoying my time building this machine… it’s worth it… so simple to fix, clear instructions”. The fact that no soldering is needed was highlighted as a big plus by educators, since it lowers the barrier to using this as a classroom project. On the filament output side, after a bit of calibration users reported they could print useful items with their recycled filament – from household organizers to cosplay props – effectively giving plastic waste a second life. One maker wrote that if you love to recycle and build, you’ll love this project, emphasizing how rewarding it is to see bottles turned into something practical. A few community members have even started local “recycling hubs” using PETmachine, where neighbors bring their bottles and watch them being turned into filament on the spot. This kind of grassroots engagement is exactly what we hoped for.
• Limitations & Improvements: Our tests did reveal some limitations, which we’ve been addressing in ongoing development. For instance, moisture in PET bottles can cause the extruded filament to be brittle or inconsistently textured. The solution was to ensure bottles are dry – we now recommend drying the plastic or the filament and even added an optional filament dryer step for humid climates. Another challenge was joining filament from multiple bottles; initially you’d end up with several short pieces of filament per bottle. We partly solved this by developing a PETwelder add-on (more on that in Next Steps) which can weld filament ends together so you can make one continuous spool from many small pieces. Diameter consistency was another focus – controlling the pull speed is key. The latest PETmachine features a PWM speed controller for the motor, allowing fine adjustments to get that perfect 1.75 mm diameter. In fact, in an independent review by Teaching Tech, it was noted that with careful tuning the filament diameter stayed within about ±0.05 mm most of the time – good enough for reliable printing. We’re continuously learning from user feedback and improving the design wherever possible (for example, we reinforced the bottle cutter module after a user suggested a tweak to better handle thick bottle walls).

Sustainability

PETmachine’s core purpose is sustainability. It directly addresses the plastic waste problem by providing a hands-on recycling solution. Every meter of filament produced by PETmachine is a meter of plastic that didn’t end up polluting the environment. A single 1.5 L PET bottle might yield only ~18 g of filament, which seems small, but consider a community workshop that can collect and process 1,000 bottles – that’s roughly 18 kg of plastic repurposed into useful items instead of being thrown away. Multiply that by many classrooms or makerspaces, and you have a tangible impact on local plastic pollution.

What makes this approach powerful is the closed-loop aspect of recycling. Instead of shipping bottles off to distant facilities, PETmachine enables recycling at the point of use. A school or hobbyist can see the entire journey of the material: bottle → filament → 3D printed object. This not only reduces the carbon footprint associated with transporting recyclables, but it also raises awareness. Students and volunteers actually learn about materials science, engineering, and environmental stewardship in the process of using PETmachine. It turns recycling into an engaging, educational activity rather than a chore.

Another sustainability angle is reducing demand for new filament production. Traditional 3D printing filament is made from virgin plastic in factories; by substituting recycled filament for some of our prints, we save on the energy and raw materials that would otherwise be used to produce new plastic filament. It’s a small step toward a circular economy in 3D printing. I’ve started using PETmachine filament for prototyping my own designs whenever possible – it’s a great feeling to know that the spool of filament I’m printing with used to be a pile of discarded bottles. And when a print made from this recycled filament reaches end-of-life, it can potentially be shredded and re-extruded again, further extending the material life cycle.

There’s also a social sustainability aspect. Because making filament from waste essentially brings the cost down to just cleaning a bottle and the electricity to run the machine, PETmachine lowers the cost barrier for 3D printing. In the Kenyan school example, once they began making their own filament, the number of student projects and prints increased dramatically – they no longer felt they had to ration a limited supply of store-bought filament. Likewise, in parts of Sierra Leone we’ve discussed deploying PETmachine in community tech hubs: locals could collect bottles (cleaning up the neighborhood) and in return receive filament which they can use to print needed items or even sell 3D-printed crafts for income. This virtuous cycle of cleaning the environment, educating youth, and fostering small entrepreneurship is exactly the kind of impact we strive for.

A great example of its potential impact is the PEThouse project in Turkey, where PETmachine is used to produce components for outdoor shelters for stray cats, made entirely from waste plastic bottles. This shows how localized production from trash can solve real environmental and humanitarian issues at once.

With just 45 watts of power consumption, PETmachine is also energy efficient. It typically processes one PET bottle in 8–15 minutes, yielding 8–15 meters of filament. That equates to around 60–90 meters (or ~80–130 grams) of filament per hour. In most countries, this costs only a few cents per hour to operate – for example, about 0.01–0.03 EUR/hour in Poland or Germany, depending on local electricity rates.

Impact & Next Steps

Since its first prototype in 2018, PETmachine has grown from a one-off idea to a small but global movement. As of today, around 2000 PETmachines are in use worldwide – from North America and Europe to classrooms in Africa and hobbyists in Asia. They’ve reached over 30 countries and counting, and are consistently receiving great reviews for their simplicity, impact, and reliability.

This journey also includes academic recognition: I was proud to present my paper “PETmachine: Turning Plastic Bottles into 3D Printing Filament” at a technology conference in Japan in 2020, showcasing the innovation on an international stage.

Some early adopters include a tech startup in the Philippines recycling local trash into 3D-printed face shield parts, a university in France using PETmachine in a research project on sustainable manufacturing, and a non-profit in Tanzania teaching girls tech skills through assembling and using the machine. This growing community of PETmachine builders regularly exchanges tips and results through our forum and social media, which helps everyone improve.

One impact I’m especially proud of is in the area of mobility and prosthetics. PETmachine has been paired with the 3DStride crutches project in field tests. In Kenya, after proving the concept, we are working to produce actual crutch parts from recycled PET. (Initially the final crutches are still made of stronger materials like ASA for maximum strength, but the goal is to incorporate recycled PET for less critical components.) The idea that an amputee football team could potentially print their own crutch parts out of plastic bottles is something that keeps us pushing forward. The path to get there involves testing material blends or reinforcements for PET (since pure PET can be a bit brittle for heavy load-bearing parts), but our ongoing research is promising. Even aside from crutches, simpler assistive devices – like cane holders, wheelchair cup holders, or finger splints – have already been made from PETmachine filament in trial runs, showing the potential of recycled filament in the medical aid space.

Looking ahead, we have a roadmap of upgrades and companion tools to further extend PETmachine’s capabilities. Some exciting next steps include:

• PETwelder & Mr. Winder: A filament splicer and auto-winder system we developed as a separate project. It can join multiple strands of filament end-to-end and wind them neatly onto a spool. This means you don’t have to print with a bunch of short pieces. For example, if you processed many small bottles, the PETwelder fuses the filament segments together using heat and pressure to create one continuous filament. Mr. Winder then automatically winds it evenly onto a spool. This add-on has already been released, and some makers are using it alongside PETmachine to streamline the entire recycling workflow.
• Automatic Coloring Module: An upcoming upgrade we’re testing is a simple add-on that can dye the filament as it’s being made. This module holds a standard permanent marker and gently presses it on the filament as it exits the nozzle, effectively turning clear PET into a colored filament. Early experiments show we can get light tints or even multi-color gradients by using multiple markers. It’s an optional, just-for-fun feature, but it showcases how modular the system is – you can snap on a coloring unit to add a bit of flair.
• Other Plastics: While PETmachine today is tuned for PET bottles, we’re exploring adaptations for recycling other plastics like PLA scraps or HDPE (the plastic used in bottle caps). One idea is a swappable extruder module with different temperature profiles and nozzle designs to handle various materials. For example, a lower-temperature module could potentially extrude PLA failed prints back into filament. These are still in R&D, but the success of PETmachine has paved the way for us to pursue them.

Additionally, we’re actively looking for collaborators – whether local NGOs, schools, or 3D print enthusiasts – to start PETmachine initiatives in more communities. The goal is to set up small “mini-factories” where people can bring their plastic waste and learn to make filament and 3D print with it. This project thrives on community feedback and co-creation.

Download & Resources

You can find the digital project files (STLs, STEP, etc.) along with documentation on our website – just search for “PETmachine” in our STORE. We’ve also made kits available for convenience:

• Essential Parts Kit – 145 EUR (includes all non-printed components)
• Advanced Parts Kit – 295 EUR (includes all the 3D printed parts too)
• Fully Assembled Machine – 350 EUR

Buying a kit also gives you access to the digital files as a free download. We want to make sure anyone, anywhere can get the parts they need to build this machine.

For those interested in the engineering and research side of this project, I’ve documented the development and results in a scientific article (mentioned earlier) titled “PETmachine: Turning Plastic Bottles into 3D Printing Filament.” This paper covers the technical details and real-world testing outcomes in depth. It was even presented at an international conference in Japan, spreading the word about DIY recycling to a wider audience.

Lastly, I want to extend an invitation: Let’s make filament, save the planet, and have fun doing it! PETmachine is more than just my project; it’s a community-driven effort to rethink waste and creativity. Build one, and join us in turning plastic problems into 3D printing possibilities. Happy recycling!