The challenges, realities & potential of sustainable 3D printing

Let’s put aside the political debates surrounding climate change and say that we should all do our bit. I, for instance, feel a great sense of achievement when I remember to wash and take a reusable cup to my local hipster coffee establishment. That was until I read a piece in Anthropocene Magazine by Pierre-Oliver Roy, which states:

“It would take between 20 and 100 uses for a reusable cup to make up for the greenhouse gas emissions of a single-use cup. For ecosystem quality indicators, it could take more than 1,000 uses.”

Those paper cups, which we’ve come to know as the devil incarnate, only make up 5% of the total carbon footprint in a cup of coffee when you take into consideration plantation, oil jet fuel, energy to roast beans, energy to make the coffee, etc.

There’s a comparison here to perceptions of additive manufacturing (AM) and sustainability. While the prospect of utilising less raw materials to manufacture a part seems, on the surface, to make complete carbon sense, the whole lifecycle of an additive manufactured part needs to be considered. How much electricity does an AM machine use for instance?

“26 is the magic number,” says Dr Phil Reeves, who in 2013 conducted a study on the very subject alongside the manufacturing trade association, GTMA. “A Selective Laser Melting machine uses 26 times more electricity to process one kilo of titanium than a CNC machine would use to machine.”

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Dr Reeves’ in-depth research, which focuses primarily on metal powder-bed fusion technology throws up so many questions that need to be asked before proclaiming additive manufacturing is in any way, shape or form sustainable; even down to the location of manufacture. The report uses an aerospace bracket as an example: to produce it in Norway, where 99% of the electricity they produce is from renewable sources, you can say that there is no CO2 attributed to the manufacture. In India, where 81% of electricity is made from fossil fuels and with their low grid efficiency, you can attribute 35 kilos of CO2 to the manufacture.

“This idea of reshoring manufacturing with AM because it’s good for the environment, is all very well in practice, but actually the efficiency of your local power generation is more important than the efficiency of distribution,” explains Dr Reeves. “Although everyone has a bee in their bonnet about the contribution to global warming of shipping, if you look at it on a weight of goods moved by emissions per mile basis, it’s by far the most environmentally friendly mode of transport.”

If this all seems a little on the negative side, fear not, the findings clearly show some incredible upsides to AM’s potential impact on the environment. Particularly when it comes to utilising titanium and aluminium powders for topologically optimised aerospace components.

The report takes into consideration the following elements for carbon footprint analysis: raw materials, manufacture, distribution, use and disposal; it takes those aspects and compares an aluminium alloy component manufactured on a CNC, an additive manufactured latticed part and a topologically optimised AM part. The results are staggering, particularly when you take into account the weight saving benefits on fuel consumption in aviation. The lifecycle CO2 emissions for the latticed AM part equalled 16,260 kg, almost three times less when compared to the 43,886 kg from the CNC machined part.

“There’s another environmental benefit of AM, which is design functionality and improved performance,” says Dr Reeves. “A processing plant project I worked on a couple years ago managed to improve the efficiency of a heat exchanger by 5%, which saved a couple of million pounds a year mainly from lowering electricity consumption. If we can design better, more efficient products it will typically manifest itself as saving energy.”

Some of the industry’s leading lights have their say on sustainability in additive manufacturing. 

Ellen Kullman | Carbon CEO

“The old adage of reduce, reuse, recycle is as relevant today as it was decades ago when it came up and hopefully we’re doing a better job at it today […] With every print there is resin left over, so we reclaim as much of it as we can and we reuse in the next print. That was a change from the first-generation printer because we understand that’s not only an economic issue for our customers, it’s a sustainability issue for our customers as well.”

Avi Reichental | Nexa3D CEO

“One man’s trash is another man’s treasure, and that adage is immensely true in the additive manufacturing world. A number of 3D printers, including the ProtoCycler and the Filabot Reclaimer, will break down single use plastics like water bottles and transform them into the raw materials that additive manufacturing carefully builds its prints from. But despite the fact that additive manufacturing is checking off all three R’s [reduce, reuse, recycle] of sustainability, there is still work to be done. Just because the field is progressing does not mean we have grounds for complacency.”

Fried Vancraen | Materialise founder & CEO

“We are proud that we defined, from the opening reception of Materialise, our mission statement that we wanted to use our knowhow in 3D printing for a better and a healthier world […] we see this just as an extension of an evolution we have been in already for a long time because sustainability is now another word to define that better and healthier world.”

Marie Langer | EOS CEO

“What is really important for me is to better communicate the advantages we have in this technology when it comes to conventional manufacturing. So many advancements like new resource efficiencies, lightweight design, longer product life, inventory waste reduction, a lot of things that we can offer with the technology in general. I want to make everyone more aware of the fact that it can be a green technology and then of course, there are a lot of things we look into either biodegradable materials [or] making sure that we reduce energy waste of our machines.”

Dr Aaron Bent | 6K CEO

“Additive is known for being a more sustainable process than conventional manufacturing, however a deeper look into supply chain shows that significant improvements can be made. The most common method for producing metal powder is a high-energy, low-yield gas atomisation process which is bad for our planet. It has a poor environmental footprint and is burdened by 75% waste – due to only 25% of material being produced at a usable size for LPBF as an example.

“Seeing the potential for huge environmental improvements was a key driver for 6K in turning to the production of AM powders. In contrast to gas atomisation, 6K’s UniMelt microwave plasma process leverages a host of feedstock materials derived from sustainable sources such as certified scrap CNC turnings, over-sized GA and even AM supports or failed builds, that would otherwise find their way to landfill. Additionally, UniMelt uses significantly less gas, our yield is near 100% of the desired powder size and is tunable to match the different AM technologies.

“The combination of a better carbon footprint, extremely high-yield and use of sustainable sources has really caught the attention of large AM super-users across various industries as they recognise that 6K is helping to drive the circular economy.”

Max Lobovsky | Formlabs CEO

“I think the long term impact that additive can make is around this idea of distributed manufacturing, a little bit of what we saw with some of this COVID production, so rather than centralised production in a couple of places and shipping things around the world, you can produce things locally on-site, reduce those transportation impacts on the environment and increase efficiency by having less waste.”

Xavier Martínez Faneca | BCN3D CEO

“The move from traditional manufacturing to additive manufacturing with the use of thermoplastics in FFF technology is a more sustainable way of producing as it eliminates the CO2 emissions associated with transporting plastic parts. At BCN3D we manufacture locally at our Barcelona headquarters, thus reducing the massive imports of parts from our 3D printers and we also produce our own parts on our machines at our own 3D Printing Farm. By manufacturing locally we can recycle and extend the life of products resulting in more efficient use of fuel and reducing greenhouse gas emissions and resource consumption. At BCN3D we like to talk about 3D printing giving productive use to different plastic filaments and obviously we manage the waste generated appropriately, but we advocate a circular recycling process so that a more rational use of these materials can be reverted to society.”

Vicki Holt | Protolabs CEO

“I am passionate about sustainability. I believe that the answers to problems we’ve got around climate change are going to come from technologies and it’s going to become from companies collaborating together to find these solutions. I’ve been very inspired by how companies have come together in this pandemic and it tells me we can solve problems around climate change and focus on sustainability.”

Dror Danai | XJet CBO

“It’s true that we often cite the environmental benefits of additive because its less wasteful than subtractive manufacturing and due to the ease of local production. However, we need to start looking at the whole picture, every stage of the process. Waste of material still happens, there are a lot of systems using support structures or in powder-based technology a lot of powder goes to waste. With some processes there’s a whole infrastructure required around the AM system itself, powder supply systems, de-powdering units, filtering and anti-static systems etc. – of course personal safety is an absolute must – but it all contributes to the environmental footprint.”

Dan Sawyer | NatureWorks 3D Business Development Officer

“The same aspects that make AM so useful: distributed manufacturing, low volume production, and customised / complex designs with a wide and growing variety of materials make collection, re-use and recycling more challenging.  Collaborating to use sustainably-sourced, renewable raw materials and creating after-use markets for recovered materials can drive us in the right direction.”

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