Biomimicry: 3D printing inspired by nature

Materials World magazine
,
1 Feb 2016

Can additive manufacturing help raise the profile of biomimicry? Khai Trung Le talks to Janine Benyus on what 3D printing means for the sustainability approach.

Additive manufacturing is nothing new. The first methods of rapid prototyping were established in the late 1980s and the technology has been an integral part of the manufacturing process since. While wider adoption has yet to match the MakerBot-in-every-home expectation of the mid-2000s, additive manufacturing remains a scintillating prospect for industry and consumers. Good news for Janine Benyus, co-founder of Biomimicry 3.8, the Biomimicry Institute and author of Biomimicry: Innovation Inspired by Nature, who believes this steady progress is the key to furthering the sustainable innovation approach.

‘Additive manufacturing is the enabling technology of biomimicry, promoting the emulation of nature. Not just of nature’s outer forms but the internal architecture that makes biological materials like bone, shell and silks fascinating. Chitin, cellulose and keratin are common raw materials, but with a unique element found in biological materials – they get their function from structure. If we are ever to truly mimic biological materials, we would have to find a way to replicate that internal architecture.’

Mimicking the techniques and feedstocks of natural manufacturing processes, 3D printing benefits from some of the inherent advantages over traditional subtractive manufacturing. Instead of taking bulk material and scaling down, additive manufacturing builds to requirements, minimising waste production and allowing control over material design on the micro-scale, affording access to a range of material properties and functionalities.

Biology meets 3D printing

Unfortunately, the similarities end there, with the current generation of commercial and industrial 3D printers far from being waste-free and energy-efficient. Materials used are often unsustainable, with low-cost desktop printers emitting ultrafine particles that may be harmful to users, and both stereolithography and fused deposition modelling materials, the most commonly used in 3D printing, were recently found to be toxic to zebrafish embryos. This limited adherence is not satisfactory to Benyus.

‘If you mimic a biological structure, but you execute it using materials that are not life-friendly, you’ve got off the bus too early. There is more to biomimicry than just form. You can also mimic the chemical process in the natural world, and you can mimic at an ecosystem level how your business model works. What we’ve been doing since 1998 is asking the question, how would nature do this? Not just come in and have one little part of the product being biomimetic – we’re looking at a more sustainable outcome. That’s why you’re hearing from us the call to make the whole process of 3D printing biomimetic. It’s where we come from.’

Other obstacles include a gradual reduction of mechanical developments in 3D printing, having reached technological maturity within the last decade. Environmental Life Cycle Analysis of Distributed Three-Dimensional Printing and Conventional Manufacturing of Polymer Products, published on ACS Sustainable Chemistry & Engineering, notes that while 3D printing is more energy efficient than machining and milling, it is less so than injection moulding, the principle manufacturing method additive manufacturing is most commonly projected to replace. Martin Hamill of SYS Systems proclaimed that 3D printing technology had remained largely unchanged within its 30-year lifetime at the Advanced Engineering 2015 expo, and this efficiency disparity is unlikely to shift within the next few years.

If change won’t come from the technology, Benyus praised product design companies Autodesk and Altair for their adherence to biomimetic processes. Biomimicry features prominently within the former’s Sustainability Workshop, an online repository of sustainable practice in engineering and design, and in many of their software packages including Altair’s OptiStruct, a structural optimisation program based on the structure of bones and their reformation along stress lines.

‘There are hundreds of biomimetic algorithms that could be used to optimise the making of things, especially as we go into 3D printing – branching algorithms, lightweighting, algorithms for internal architecture that mimic toughness in the natural world. I think you’ll look back and say that this was the very beginning of biology meeting 3D printing. But it’s not there yet.’

The silkworm and the inkjet

‘The reason it’s not there yet is because it’s such a nascent science,’ Benyus remarked, attributing the still-emergent interest in 3D printing and a lack of compatibility between biologists and engineers and designers for the fluctuating adoption of biomimetic processes. ‘Frankly, there weren’t too many people trained in biomimicry when we started in 1998. We had to train biologists to sit at the design table, and architects and designers to work with biologists and biological intelligence.’

However, Benyus was keen to distance her intentions for biomimetic 3D printing from examples of bio-utilisation, such as MIT Media Lab’s Silk Pavilion project. Headed by Professor Neri Oxman and intended to explore digital and biological fabrication techniques and demonstrate the current limitations of 3D printing, a 1km silk strand was first woven into a 26-panel dome framework before 6,500 silkworms were deposited to complete the structure. MIT’s Rory Stott commented on how ‘the blind instinct of the silkworm is sometimes revealed as almost machine-like […] the way it connects the dots between the world of information technology and biology.’

Benyus said, ‘In the case of bio-utilisation, you’re harvesting a product. In bio-assistance, you’re domesticating the producer. In biomimicry, you’re becoming the producer. A Silk Pavilion that was truly biomimetic would be one from a fibre with silk characteristics that we created ourselves. I suppose the inkjet printer is our silkworm, how much further can we take it? The Silk Pavilion is not quite biomimicry, but shows us who we should be mimicking.’

Democratisation of making

While 3D printing may be a natural fit for biomimicry, its own status as an emerging technology may need to be resolved before it can take up the mantle of sustainable manufacturing.

‘3D printing as an everyman’s tool is nascent too. Now that it’s a tool for the democratisation of making, it’s becoming even more important. I talk about manufacturing as coming home, both in desktop and neighbourhood print shops, but the beginning of a major revolution is the time to put the ethics in and identify the code of conduct. When that happens, it would be a shame to repeat the mistakes of the Industrial Revolution – the last thing we need is another trashcan outside our homes labelled “industrial waste”. A circular economy needs to happen – what goes into the printer becomes a product, and that product should be able to go back into the printer.’

Promoting the tenets of biomimicry within the additive manufacturing industries, she says, will require both ‘a conscious emulation of life’s genius’ linked with governance between trade associations to establish best practices, establishing a supply chain dedicated to discovering more sustainable materials, a focus from printer manufacturers to prioritise these sustainable materials, and self-governance from all parties to remain committed.

No small task, but Benyus is adamant that the answer lies in looking out of the window. ‘Nature provides this amazing playbook that has not only chemistry of the material but chemistry of the printer, blueprints of the actual build file, return logistics and disassembly chemistry. If you’re looking for best practices, what biomimicry offers is the methodology by which life has conducted additive manufacturing for 3.8 billion years.

‘Ever since I wrote Biomimicry: Innovation Inspired by Nature back in 1997, I realised that if we are ever to truly mimic biological materials, we would have to find a way to get that internal architecture replicated. Additive manufacturing gives this opportunity. It is the enabler of true mimicry of the brilliance of biological materials, and the ability to use structure to grant multiple functions.’