A Rising Problem
It’s hard to get a handle on the exact the statistics of how much waste 3D printing produces.
This is especially true given as the process advances into the homes of more and more hobbyists each year.
But there are estimates out there.
Filamentive sent out a survey in early 2019, and based on its more than 200 responses, the company projects that 8 thousand tons of 3D printing material will go straight into landfills around the world this year.
To help visualize the situation, the University of California at Berkeley noted in 2017 that their own set of 100 3D printers produced at least 212 kilograms of trashed filament that year.
Those are serious numbers that add to the already alarming amount of plastics that get tossed out daily.
A First Step in the Right Direction
Fortunately, the most popular 3D printing material, PLA, is at least partially biodegradable.
It’s made from cornstarch, so it breaks down easier than filaments that are made from synthetic materials like ABS.
Looking a little deeper, PLA is a thermoplastic polyester polymer, and you might recognize parts of this label.
“Thermoplastic” means a type of plastic that becomes soft and can be molded once it’s heated to a certain temperature. And “polyester” refers to more than a type of clothing; in this case, it’s a polymer that includes naturally-occurring chemicals like the cutin of plant cuticles.
Basically, PLA uses the waxy parts of plants to form its shape, and that helps it break down into biodegradable parts instead of staying whole in a landfill forever.
But the question is, can you recycle PLA?
The short answer is, you can definitely recycle PLA filament, but not in the same way you can recycle your milk jugs, food containers, and other types of everyday plastic.
PLA has a lower melting point than other plastics, so it can’t go into the same bundle with the rest.
The two main ways to recycle PLA are to hand it over to a recycling plant that knows how to handle it or to grind it up and extrude it into new filament.
Below, we’ll go into detail on how to specifically recycle or resuse PLA filament.
After all, plastic problems require creative solutions.
Pros & Cons
So why should you go through the trouble to recycle or reuse PLA filament in the first place?
Beyond the environmental impact, there are several personal upsides to utilizing this process.
- REDUCED WASTE
Even when everything goes perfectly, 3D printing can still produce a lot of waste. Recycling and reusing your PLA is a great way to start being kinder to the environment without giving up your hobby or business model.
When you put your detached supports and failed prints back into your process or someone else’s, that’s a few pieces you’re keeping out of landfills, which is beneficial to us all.
- SAVED MONEY
You can totally save money by shredding and re-extruding undesired PLA, but there’s a caveat: You’ll first have to invest some money (and time), especially in the area of DIY.
Since creating your own filament means investing in filament recycling equipment, you won’t see a monetary advantage until you use your DIY filament long enough to save more than you put into your initial investment.
Additionally, the filament you make from your PLA scraps will need to meet performance standards for your printing needs, otherwise it’ll go directly back into your “fail” pile.
That said, another way to save money using recycled filament is through programs that offer you credit for material.
An example company that offers such a deal is RePLAy 3D, which offers filament discounts based on the weight of returned scraps.
- COMBINED SCRAPS
If you’re interested in recycling your own filament, keep all your discarded prints stored together, adding to them over time until you’ve got enough to turn them into material for a new project.
It’s a lot easier to see how much you have and map out the best use of it.
- COOL COLORS
Recycling and reusing your PLA filament waste is also a great way to jump-start your 3D printing creativity if you’re up for more DIY.
Have a bunch of unmatched colors in your cast-offs?
Brush up on your color wheel and see which can be combined into colors you need but don’t have yet (like green from blue and yellow or purple from red and blue).
Combine them to make your own one-of-a-kind hues and patterns for a truly unique DIY experience.
Recycling and reusing PLA filament isn’t always smooth sailing.
Here are some issues you may have to troubleshoot if you decide to go this route.
- COMPLEX PROCESS
Unfortunately, recycling PLA isn’t as easy as rinsing it off and leaving it in your recycling bin with your normal pile.
Its molecular composition gives it a lower melting point than other recyclable plastics, so if it gets mixed into those, it will stay solid while the rest is processed around it, causing issues for the recycling plant.
Because of this, PLA is considered an “other” plastic.
And unless you’re incorporating a Resin Identification Code into each of your PLA prints, they won’t even be identifiable as such, meaning most communities won’t let you recycle unidentified plastics.
Contact your local materials recovery facility to see what kinds of plastics they accept and consider whether you can meet all their guidelines before you recycle your PLA filament.
- SIGNIFICANT INVESTMENT
If your community recycling center doesn’t accept PLA, you’ll have to search further and find a specialty service that will do it for you.
In that case, you may have to pay a fee.
On the DIY side of things, as mentioned previously, filament recycling equipment isn’t cheap.
And unless you’re willing to put in the effort (to perfect the process) and time (to offset the initial cost), it may never actually be worth it.
- POOR PERFORMANCE
Again, unless done perfectly, there’s a noticeable loss of performance in re-extruded filament.
Its tensile strength is reduced from around 40 to 35 MPa, which is enough to create a much higher chance of breakage while being extruded by your 3D printer.
It also means a higher chance of warpage, which can push your whole object out of shape.
If you’re worried about the quality of your DIY recycled PLA, your best bet will be to send your scraps to a professional PLA recycler and to buy professionally-recycled filament (hopefully from the same organisation).
Ways to Recycle & Reuse
If you’re ready to commit to the process, recycling or reusing your PLA is a great way to minimize your 3D printing waste.
As we mentioned, you can’t just leave it out in your regular bins, but there are a few ways to make it work.
PLA is considered biodegradable to a large degree because of its organic origins.
This means that, if left undisturbed, it will eventually be broken down by naturally-occurring microorganisms like bacteria and fungi.
Services that specialize in PLA can compost used filament faster since they have the equipment needed to create environments that are warm enough and composed properly.
(Ideal conditions for PLA biodegradation include a specific ratio of plastic to organic mass.)
In these centers, composting PLA typically takes one to three months, whereas it can take up to six if you attempt it at home.
Sending your PLA to the proper center also minimizes the chance that pieces of PLA will remain in your compost, so we recommend letting the experts handle this.
The easiest way to take care of PLA filament that you don’t want anymore is to give it to recycling centers that know how to handle it properly.
Local centers exist in most large cities, but if you’d rather outsource your recycling, there are several services that let you box up your PLA and send it to them.
Filabot (which also has its own line of DIY filament extruders) makes it extremely simple.
And we’ll remind you one more time that RePLAy 3D lets you do the same with no obligation to buy anything. It’s a great service!
Creating Your Own Filament
With accessible machines like the FilaMaker, Filabot, and Recyclebot, you can grind up your PLA scraps and extrude them as usable filament.
This kind of equipment squeezes your PLA into shape again, to be wound around spools like they’ve never been used before.
They’re great for 3D printing enthusiasts who like to experiment and go free form with their designs.
With the right machines and practice, you can turn your mistakes into new materials.
As you can see, there are a number of ways to keep your used PLA filament from piling up, either on your shelf or in the dump.
Published on all3dp.com