What make 3D Printing Sustainable?

In our previous article of the sustainability series “How Sustainable is 3D Printing?” We delved into the environmental impact of 3D printing, mainly from the widespread everyday use of desktop FDM printers. Now, the question is, What to do now? So, as you try to answer this matter, new questions emerge due to it being, in reality, a multidimensional issue with countless perspectives to take in mind.

Do we have proper sorting systems and proper legislation? Unfortunately, not all the answers offer meaningful solutions. For example, what sustainable measures are truly impactful, and what are just greenwashing strategies? To what degree do political and economic interests play a role in how society handles sustainability? Now, regarding 3D printing, are there more sustainable alternatives to our standard practices and material choices? How truly recyclable are 3D printing plastics?

As I progressed in my research, I realised that finding answers is genuinely challenging, and nobody has the ultimate solution. So, I don’t pretend to provide a definitive answer to this broad and complex subject with this article. And I can understand that adopting sustainable measures takes time, energy and compromise. Still, I hope this article can at least plant a seed for those aiming to adopt more conscious practices in their 3D printing practices.

For now, I decided to tackle sustainable solutions from three perspectives: 3D printing and recycling, alternative materials adoption, and the embracing of circular economies.

3D Printing and Recycling

To set the bases of this section, we’re leaving metals for another occasion and focus only on plastics, given their wider use and environmental impacts. It is no secret how the production of plastics has come out of hand. One piece of plastic can take years, decades or even centuries to disintegrate. Meanwhile, production raises and our means to manage leftovers leads to environmental issues like huge landfill mountains, ocean pollution and a significant contribution to carbon and other toxic emissions. Now, among plastics, how do we define recyclability? Let’s take this last year article as a starting point for our classification. There’re two major types of plastics: Thermoplastics and thermosets.

On the one hand, thermoplastics are easier to handle, given that you can control their properties with a change of temperature. On the other hand, thermosets aren’t reversible. Once you manufacture something with a thermoset, you can’t melt it back into its raw material for reuse. Regarding 3D printing materials, FDM filaments are mostly thermoplastics, while SLA resins are mostly thermosets. So, yes, you can’t recycle photopolymer resins. Now, what about polyamide powders used in SLS processes? Polyamides are thermoplastics and, potentially, recyclable, but for now, let’s focus on FDM filaments.

Well, how do we classify thermoplastics? If you check daily use plastic packagings, you might notice a triangle with a number inside. These numbers are a standard system to sort out the most common-use plastics; it ranges from 1-7. The following are the classifications with some examples:

1. PETE: Water and soda pop bottles
2. HDPE: Detergent, shampoo and milk containers
3. PVC: Pipes and medical tubing
4. LDPE: Grocery bags and wrapping films
5. PP: Tupperwares, yoghurt cups and most medicine containers
6. PS: Food containers, packaging foams, insulation foams
7. Others

Fortunately, 1 and 2 are the easiest to recycle; given their widespread use, legislation, sorting systems and waste management plants are commonplace. Now, 3 to 6 are harder to manage and, in practice, they’re rarely recycled since there’s low incentive to do so; Consider that investing in treatment plants is costly. Finally, type 7 are mostly non-recyclable and, unfortunately, common 3D printing plastics like PLA, ABS, Nylon and TPU fall under this category.

But, what about PETG? Can we sort PETG waste alongside PETE bottles? Well, this seems to be the case for most legislations; however, not all agree. For example, in California (USA), PETG was excluded from the type 1 classification. PETG thermal properties are different from standard PETE, and thus, mixing both materials could cause processing issues. Recycling compliances vary from region to region, and unfortunately, we haven’t reached a global consensus on this issue despite its relevancy and high impact collectively nowadays.

And, isn’t PLA biodegradable? Well, not exactly. There’s a common misconception that since PLA is bio-based (Instead of fossil-based), it is also biodegradable; Nonetheless, it still has the same effect in landfills and oceans as common plastics do. The only way to biodegrade PLA is through specialised industrial composting processes, and, unfortunately, we still lack proper infrastructure. But, at least, handling PLA involves fewer carbon emissions than conventional fossil-based plastics, which is an immense plus.

So, what can we do to repurpose filaments if they aren’t recyclable? Well, we can still extrude new filament spools from our print waste. Many commercially available options like the ReDeTec Protocyler+ offer high-quality extrusion results. Watch the video below!

Having a filament extruder in your house can be costly. The good news is that many brands, like Filamentive, offer recycled filament options. They recycle both post-consumer and post-industrial waste to produce their filaments.

Alternative Materials

With the current 3D plastics environmental issues in mind, the natural question that follows is: Are there more sustainable materials available? Let’s see if that’s the case.

PHA: A Legitimate Alternative to PLA?

Polyhydroxyalkanoates (PHA) is a group of plastics synthesised through bacterial fermentation from food waste. Unlike PLA, which could take 80 years to degrade in nature fully, PHA takes around a year. Although it still has a reduced market and is currently more expensive than conventional plastics, many companies like Genecis invest in R&D to exploit its full potential. Genecis developed a method for converting food waste into PHA and believes it can do so at the cost of 40% less than mainstream commercial methods.

Are there commercially available PHA filament options? Unfortunately, there’s still no evidence of PHA being 100% reliable for 3D printing, at least not in its pure form. However, Colorfabb took the first steps with its PLA/PHA blend. But recently, the filament producer Fillamentum released what they claim to be the first 100% biodegradable filament, NonOilen. This biobased filament is a blend of PLA and PHB (A plastic under the PHA family). After ending its life as a finished product, you can send it to an industrial or home food waste composter.

Cellulose: Natural Occurring Polymer

Cellulose is the most abundant organic polymer on earth; you can find it in wood, plants, paper and natural fibres. Just like PHA, researchers are looking for ways to adapt it to 3D printing. So far, the biomaterials company UPM offers the cellulose-based PLA blend UPM Formi 3D, which delivers results almost identical to wood.

Algae: A Carbon Negative Solution?

Now, what if we set the stakes even higher and think about a bioplastic that, beyond being carbon neutral, actively absorbs CO2 from the atmosphere? Actors like Algix and Klarenbeek & Dros Studio have been experimenting for years with ways to leverage the expansion and democratisation of plastic production through 3D printing to develop a production model based on seaweed.

Since it is easy, quick and cheap to grow, the resulting bioplastic can be produced and managed locally. This aquatic resource is one of the most effective sources of photosynthetic processes in the world. After transforming CO2 into O2, they leave a byproduct that can be polymerised into a bioplastic. Though currently, you must bind this material with other bioplastics like PLA, researchers are confident of its potential as an established alternative to fossil sources at industrial levels.

Other Solutions

PLA organic blends based on alternative ingredients like hemp, coffee and beer are spreading through maker communities at increasing rates. I’m hopeful we’ll be seeing mind-blowing innovations and new windows into unexpected sustainability innovations in the near future; it has to happen. Many solutions we’ve discussed so far, like Filamentive, NonOilen and UPM Formi 3D, and many more, are part of the Ultimaker Material Alliance.

Since the desktop 3D printing culture skyrocketed a decade ago, we strongly associate this technology with plastics and, to a lesser degree, with metals. But, what about the third engineering material, ceramics? This group of materials are much cleaner when compared to the other two. So the good news is that they’re becoming more printable every day, and affordable desktop options are available on the market; so why not giving them a try? For more information on ceramics 3D printing, click here!

The Circular Economy Mindset for 3D Printing

Innovation through the development of more sustainable materials and technologies is extremely important. But, perhaps, there’s something with an even more meaningful impact: A change in mindset. What if we think of 3D printing as part of a supply chain as a whole instead of as an isolated process? Sustainability requires the conservation of energy and resources for future applications. However, a linear supply chain relies heavily on constantly extracting natural resources after generating waste endlessly. What if we curve that chain, closing it into a loop? But for that, we require an active conscious role from all the players involved.

Just like it happens in nature, we need to balance the network between manufacturers, consumers, retailers, legislators, investors, etcetera into an efficient and self-aware ecosystem. Knowing that 3D printing is reinventing manufacturing, it is also the case for its supply chains. So, how do we do that? Well, it is a broad subject in and of itself, and we could spend countless articles to get a fully comprehensive view. But we can start with design and data.

Just as we ponder requirements (customer demand, quality, costs, aesthetics, etc.) as part of the design process, we could also think of requirements in a broader sense throughout a complete product life-cycle. Moreover, how do we optimally manage such complex sets of data? Thankfully, digital technologies like server infrastructures, the internet of things, and cloud platforms enable all the parts involved to track constant feedback, ultimately leading to more sustainable decisions.

One excellent example of a platform based on sustainability is Ecologi. With its unique profile-based system, it promotes collaborative projects to tackle sustainability issues within a worldwide network. SolidPrint is among one of its proud members, and you can follow our profile here! For more information, please call SolidPrint at 01926 333 777 or email info@solidprint3d.co.uk.

Further Readings

• Paralympic Athlete 3D Prints Adaptive Sports Equipment
• How 3D Printing Is Making Manufacturing More Sustainable!