It’s true that 3D printing is driving some recycling efforts and technology, but these are still just getting started. While there will surely be advancements in the future, there are already a number of options for buying or producing your own recycled plastic filament or even printing with recycled plastic pellets. There are challenges and drawbacks to be sure, but it’s well within the reach of many makers to print with recycled plastic.
There are also options to recycle failed prints, but they generally aren’t as practical. Some services, like the one offered by RePLAy 3D, not only allow you to buy filament, but also offer to recycle your failed prints. This adds up to reduced waste and lower costs while also encouraging environmental conservation efforts.
There are plenty of options to consider. Let’s take a look at some of the most promising projects and products that enable us to print with recycled plastic and how you can do it yourself!
One of the most obvious and common methods to print with recycled plastic is to grind, melt, and extrude plastics to produce filament.
Though it could save you around 80% on filament costs, the problem with this method, other than maintaining quality and uniformity, is that when repeated, the heat involved generally produces a lower grade of plastic. Repeating the process again further degrades the properties of the material until it must be recycled in some other way to produce a usable product.
Though generally a pricier option (as you typically have to pay for mechanical parts), some DIY systems can be made for as little as $200! (If that number still seems high, consider that you’ll probably reach that amount in 5 to 10 1-kg spools of filament.)
Some companies use proprietary methods and don’t say how they produce recycled filament, such as with B-PET filament. Some, like Re-Flow, have experimented with bio-based alternative plastics and use “monomer recycling” to chemically break down plastics, eliminating the problem of degraded performance in recycled filament.
Various projects have used systems for grinding bottles and other plastic waste and extruding them into filament.
The Recyclebot is a relatively affordable DIY option for hobbyists to accomplish the task, depending on which version you make. Variations on such a system have been used to do things like turning plastic waste into car parts in Venezuela, making things like transmission gear cogs, and producing filament for as little as $17 per kilogram.
The Perpetual Plastic Project uses a similar setup in a mobile recycling installation that can be booked for events. One company has even opted to eliminate the extrusion process entirely, producing a printer that can use cheaper recycled plastic pellets.
These systems all have the advantage of removing waste from the environment, reducing material costs, and producing products with nearly the same properties as “virgin” plastics. The downside to this is that it can be difficult to acquire, sort, and clean plastics, and melting degrades the polymers enough that there’s a limit to the number of times it can be usefully recycled.
These filaments come with a couple of advantages, namely that they’re commercially available and they allow you to use recycled material without the need for a complex recycling system to produce quality filament. Generally speaking, they tend to perform comparably to their non-recycled counterparts. For example, rABS is suitable to print anything you would print with regular ABS.
The biggest downside is that, if you’re buying it ready-made, it costs more than if you were to produce your own recycled filament. Otherwise, many prominent makers give recycled filament great reviews, on-par with everyday commercial filaments.
Reflow uses a monomer recycling process to break down plastics without melting them. This allows them to recycle plastics that were previously not recyclable, while also eliminating the normal degradation problems associated with melting and re-forming thermoplastics.
While it’s proprietary and therefore hard to say for sure, we think it may be more sustainable, as it doesn’t need to expend energy grinding and melting waste plastic.
Reflow is also attempting to develop a filament made from polyethylene furanoate (PEF), a “bio-based” plastic. Russian researchers developed the material and have successfully printed with it using an Ultimaker 2 machine. While it isn’t yet broadly available, PEF shows promise because it’s biodegradable to a higher degree than PLA and has desirable thermal and mechanical characteristics.
There’s a number of advantages and disadvantages to DIY filament making. For example, the Recyclebot initially produced less than ideal quality filament. According to 3D Printing Nerd’s review of the Felfil, it isn’t good enough to produce consistent results, so this is one problem that plagues even professionally-designed and built products.
Thankfully, the community is rising to meet many of the challenges as time progresses. Things are slowly changing thanks to innovations like this improved diameter sensor, which supposedly allows the Recyclebot to produce filament with a diameter accuracy of 0.01 mm. If it performs as advertised, you can have an accurate diameter of filament with a sensor that costs under $6 to produce, unlike commercial sensor systems that can cost anywhere between $55 and $1,000.
Other classic problems you might face are moisture and humidity, as cooling filament and spooling it properly also affects the diameter. In contrast, if you’re buying recycled filament from a company like Filamentive, you can expect performance and consistency on par with other commercial filaments.
You may have a relatively difficult and costly path ahead if you intend to produce quality filament yourself, but it’s not impossible and it could save you a bundle if you’re up for the challenge. For more on recycled filament, be sure to check out All3DP’s Filament Recycler’s Guide.
Even hobbyists at home can buy or produce recycled filament and start printing with it, although there are limitations. Companies are racing to solve the problems of material costs and pollution by developing better printers, recycling systems, and even new biodegradable plastics. But that race has only just begun. As the demand grows, more options and opportunities continue to crop up.
One company even made a 3D pen that uses plastic bottles as filament. Advances in the field of materials science alone may yet bring stronger, more environmentally-friendly filament options for makers in the near future. Perhaps one day, we may discover a biodegradable “wonder-material” similar to PEF, something that can be widely used and economically recycled.
License: The text of "3D Printers & Recycled Plastic: Can They Print Recycled Plastic?" by All3DP is licensed under a Creative Commons Attribution 4.0 International License.
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