Note 03: I fell down a filament rabbit hole

I have always loved modelling things in 3D on the computer, but there was one thing that used to frustrate me: I could create something digitally, spin it around on screen and inspect it from every conceivable angle… but I couldn't actually hold it.

Interestingly, my relationship with 3D printing actually goes back much further than my little printer sitting beside my desk now. During my sixth-form years, I completed an EPQ exploring the relationship between maths and art. Part of the project involved using mathematical equations to generate three-dimensional forms digitally, which I then 3D printed. The idea was that these forms would eventually become the basis for a sculpture. What happened to those models afterwards?

Absolutely no idea!

After that venture, I didn't touch a 3D printer for years. At the time they felt like expensive, specialist pieces of equipment rather than something I could realistically have at home.  Then, earlier this year, along came the idea for The Collective Quarter. Because I knew I would be creating physical miniature models as part of the project, I started looking for something that could help me translate my digital designs into tiny physical components. My hand-building skills are… variable, shall we say.

Initially I looked at laser cutters because I had used them quite a lot before, but buying one for home was simply too expensive. Out of curiosity, I started looking at 3D printers instead and was genuinely surprised by how much more accessible they had become. Eventually, I bit the bullet and bought a Bambu Lab A1.

Six months later, I use it constantly.

I've printed tiny furniture, lettering, logos and components for my models, alongside various useful bits and pieces for around the house. It has opened up a completely new avenue for how I design because something no longer has to remain trapped inside SketchUp or Fusion 360. I can make it, hold it, test it and change it.

But there is one thought that has kept popping into my head every time I empty the little pile of leftover filament into the bin:

How sustainable is this, actually?

I already try to minimise the amount of material I use. I don't print things just for the sake of printing them, and I tend to make small objects with relatively short print times. But every print still produces some waste. Supports, little purge pieces, test sections and, occasionally, the sad remains of a print that didn't quite go to plan. And currently?

That waste goes into the bin.

Which doesn't sit particularly comfortably with somebody who talks about circularity and responsible material choices as much as I do. So, naturally, a rabbit hole began.

First: what am I actually printing with?

Most of the filament I currently use is PLA, which is one of the most common materials for desktop 3D printing.

PLA is interesting because its raw material can come from renewable plant sources, rather than being entirely fossil-fuel based. For example, Bambu describes the PLA used in some of its filaments as being derived from sources including corn and sugarcane. At first glance that sounds wonderfully reassuring. Plant = compostable = problem solved. Unfortunately, not quite.

Although PLA is often described as biodegradable or compostable, that doesn't mean I can pop my failed miniature chair into the compost bin with the potato peelings. In practice, PLA generally needs controlled industrial conditions to break down properly, and there isn't good evidence that it will meaningfully biodegrade in ordinary soil or home composting conditions. So although the beginning of its life can look considerably better than a conventional petroleum-based plastic, the end of its life still needs some thought.

Could I recycle it instead?

Thankfully, I discovered I am very far from being the only person wondering what to do with a growing container of oddly shaped pieces of filament. There are now companies in the UK specifically dealing with 3D-printing waste, accepting things such as failed PLA prints, supports and leftover filament etc… so the material can be recycled, pelletised or otherwise diverted from landfill. Depending on the scheme, paid recycling boxes for small-scale users appear to start at around the £50 mark. There are also supplier-led schemes, Filamentive, for example, currently offers PLA waste recycling to qualifying UK customers through its recycling partner. Considering a box would probably take me well over a year to fill, paying around £50-ish suddenly doesn't seem like an enormous investment.

My current plan is therefore very simple:

stop throwing the scraps away.

I'll keep a container beside the printer, collect everything and send it to a specialist recycler once I've accumulated enough.

Very glamorous.

Very revolutionary.

A box of plastic scraps under my desk.

But sometimes sustainability really is that unexciting.

Or could I recycle it myself?

This was where the rabbit hole got deeper. You can actually buy desktop machines that shred or melt waste filament and extrude it back into usable filament. Which is objectively very cool. There was approximately a five-minute period where I thought, obviously I need one of those. Then I remembered who I am. Realistically, I suspect I would enthusiastically recycle filament for approximately three weeks before the machine became another object sitting in the studio glaring at me. Buying another electrical appliance in an attempt to become more sustainable, and then barely using it, feels slightly counterproductive.

So, for me, sending scraps away to an established recycling system feels like the more realistic option. And I think that is an important part of sustainable design generally.

The theoretically perfect solution isn't necessarily the most sustainable one if it doesn't work with the person actually using it.

Then I discovered PHA

One material that really caught my attention during all of this was PHA. Like PLA, PHA can be bio-based, but its end-of-life possibilities are particularly interesting. Recent research into commercially available pure PHA filament found that printed samples began biodegrading under real-world home conditions, including soil and home compost, while the PLA samples did not. It can also be printed at lower temperatures than PLA, which potentially reduces some of the energy needed during printing.

There are trade-offs, of course. The same research found differences in mechanical performance and some additional challenges with things like warping, so this isn't a case of declaring PHA the magical sustainable filament and replacing everything immediately. It does, however, give me another material to explore.

Next time I need to buy filament, rather than automatically replacing a roll with exactly the same thing, I want to look more carefully at what is available, including PHA, recycled-content filaments and other genuinely lower-impact options. They often come at a premium compared with standard PLA, but for the fairly small quantities I use, spending a few pounds more on a thoughtfully chosen material feels worthwhile.

Perhaps the biggest change isn't the material at all

The more I read, the more I realised that sustainable 3D printing isn't just about finding the perfect filament. It is also about how you print.

• Reducing supports by changing the orientation of a model.

• Splitting something into components if doing so uses less material.

• Checking settings before committing to a print.

• Making prototypes carefully so you don't end up printing version one, two, three, four and five unnecessarily.

• And perhaps most importantly, asking whether something actually needs to be printed in the first place.

When I look at how I currently work, I think I probably sit somewhere in the middle. I'm certainly not operating a zero-waste 3D-printing studio. But I do try to make considered decisions. 

• I don't press print until I'm happy with the design and reasonably confident it will work. 

• I check the setup first to reduce the chance of a failed print. 

• Most of the things I make are small and take less than an hour to print. 

• And increasingly, I've found myself using the printer to make small replacement parts or useful objects around the house rather than immediately ordering a new product online.

• I also tend to choose filament supplied on cardboard reels rather than plastic ones where I can.

So there are already some good habits there. But there is definitely room to do better.

For now, my little sustainable-3D-printing plan looks something like this:

• Collect and recycle my PLA scraps rather than binning them.

• Be more thoughtful about the filament I buy next.

• Keep designing prints to minimise unnecessary material and supports.

• And continue using the printer as a tool to solve an actual problem rather than as an excuse to create more stuff.

Final thoughts

This is something that has been niggling at me for quite a while, so I'm glad I finally sat down, disappeared into the research rabbit hole and worked out what I can realistically change. 

3D printing has opened up a completely new avenue of design for me. Being able to move so easily between digital modelling and physical making has genuinely changed the way I work. I don't want to stop using it. I just want to make sure that, as the technology becomes a bigger part of my practice, I'm thinking about its impact too. Because perhaps responsible design isn't about never using materials or processes that have an environmental footprint.

Maybe it's about understanding that footprint well enough to make better choices with them.