Could we really 3d print buildings using drones?

Well, it's a start: 3d printed model buildings on display at the 2015 International CES trade show. Image: Getty.

These days, 3D printing is never far from the public eye. Its vast and imaginative array of applications is constantly growing, from life-saving medical implants to life-ending firearms. Now, architects and structural engineers have started experimenting with the technology in an effort to, quite literally, change the world we live in.

There’s no denying that 3D printing holds great potential for larger-scale projects such as buildings and bridges. It could realise complex shapes that would be unachievable using standard building techniques. It could modify existing structures, for example by putting more insulation onto outer walls, or more strength into stairwells. Taken to the extreme, a building could be printed with all its plumbing, pipework and electrical wiring already in place.

It sounds exciting. But let’s set the hype aside for a moment, to consider what 3D printing can actually achieve right now.

Waste not

So far, the technology has two outstanding features: it can manipulate a range of materials, and it can help to reduce waste. While the cheaper, basic machines are limited to plastics, more complex 3D printers can fuse powdered raw materials such as gypsum (like chalk dust), metal powder (like steel) or polymers (nylon) into complete objects.

In much the same way that a 2D printer can produce a whole spectrum of colours by mixing different proportions of cyan, magenta and yellow ink, advanced 3D printers can combine two or more materials to alter the physical properties of printed objects: from colour, to strength, to electrical conductivity and even thermal insulation.

These advanced printers work by sprinkling powdered materials onto the print area layer by layer, fusing the particles of each layer together according to a given design. When the print is finished, excess powder can simply be shaken off and reused, leaving only the fused material in the desired shape. This is much more efficient than the standard practice of cutting away at a large block of material until you have the shape you want.


We’re gonna need a bigger printer

But the technology does have its limitiations: for architects and engineers, the main stumbling block to date has been size. As a general rule, a printed object must be smaller than the machine that prints it. Not to be thwarted, architects and engineers have been coming up with inventive ways to solve this problem. Some of the latest and greatest ideas were on show at a major symposium, which I presented at last summer.

There were two fascinating presentations, for example, by engineering firm Arup. They created a 3D printing process which joins steel tubes together, using only a quarter of the material of the standard process.

Meanwhile, at the 3D Print Canal House project, technologists were tackling the size problem head on. They scaled up existing technology to create a 6m high 3D printer, capable of producing plastic wall panels with very complex shapes, which are then filled with concrete for structural strength. By contrast, Chinese firm WinSun developed a very large printer which uses liquid concrete to produce full-size, 3D-printed building panels that can be assembled into a finished structure.

Dutch firm MX3d have managed to get even closer to printing an entire structure in one piece: the team there have developed a 3D printing robotic arm, which extrudes molten steel that quickly cools and solidifies, in a similar manner to the fun, plastic 3D printing pen toys available on the market.

Since the robot can move around on rails, or even on the structure itself, it can 3D print in the open air. The firm hopes to print a steel pedestrian bridge over an Amsterdam canal, but they are yet to find a site.

My colleagues at the University of Bath are involved in an even more ambitious project alongside others to develop automated, flying, 3D printing drones. These will be able to 3D print buildings, without the constraint of being anchored to the ground.

Not there yet

Despite all these developments, a few obstacles remain. Constructing buildings and 3D printing both require materials with particular properties – and these requirements don’t always overlap.

For example, concrete seems like an obvious choice for 3D-printed architecture, since it can be transported as a liquid and sets very hard. But while concrete is strong in resisting compression (being squashed), it does not work well when in tension (being pulled). Concrete floors generally have steel reinforcement bars in their lower face, to resist the tension that’s caused by bending. So 3D printing with concrete will not be effective, unless we can find a way to improve its resistance to tension.

At the moment, research in this field is focused on introducing small fibres into liquid concrete, to provide some tensile strength without compromising its ability to flow through 3D printing machinery. Others are looking at ways to automatically “print” the reinforcing bars within the concrete.

Testing, testing

What’s more, there’s still a lot we don’t know about the structural strength of the 3D printed objects – in particular, the effect of building up a solid object from fine layers. This information is critical if we’re to have confidence in the ability of 3D-printed buildings to withstand both everyday use, and extreme conditions such as earthquakes or storms.

I have just started work on a project which aims to do just that, with a view to building a mathematical model of how different layering, direction and speed of printing affects the final strength of the object. This will allow structural engineers to understand and adapt their designs to suit the specifications of 3D-printed buildings, when they do eventually come along.

But it’s important to ensure that 3D printing doesn’t just become a solution looking for a problem. It doesn’t take an ornate, steel-welding robot to build an environmentally sustainable bridge, when it could be constructed with simple wooden planks. While 3D printing will no doubt become a valuable tool in the architect’s arsenal, we need to wield it carefully.The Conversation

Paul Shepherd is a lecturer in digital architectonics at the University of Bath.

This article was originally published on The Conversation. Read the original article.

 
 
 
 

CityMetric is now City Monitor! Come see us at our new home

City Monitor is now live in beta at citymonitor.ai.

CityMetric is now City Monitor, a name that reflects both a ramping up of our ambitions as well as our membership in a network of like-minded publications from New Statesman Media Group. Our new site is now live in beta, so please visit us there going forward. Here’s what CityMetric readers should know about this exciting transition.  

Regular CityMetric readers may have already noticed a few changes around here since the spring. CityMetric’s beloved founding editor, Jonn Elledge, has moved on to some new adventures, and a new team has formed to take the site into the future. It’s led by yours truly – I’m Sommer Mathis, the editor-in-chief of City Monitor. Hello!

My background includes having served as the founding editor of CityLab, editor-in-chief of Atlas Obscura, and editor-in-chief of DCist, a local news publication in the District of Columbia. I’ve been reporting on and writing about cities in one way or another for the past 15 years. To me, there is no more important story in the world right now than how cities are changing and adapting to an increasingly challenging global landscape. The majority of the world’s population lives in cities, and if we’re ever going to be able to tackle the most pressing issues currently facing our planet – the climate emergency, rising inequality, the Covid-19 pandemic ­­­– cities are going to have to lead the way.

That’s why City Monitor is now a global publication dedicated to the future of cities everywhere – not just in the UK (nor for that matter just in the US, where I live). Our mission is to help our readers, many of whom are in leadership positions around the globe, navigate how cities are changing and discover what’s next in the world of urban policy. We’ll do that through original reporting, expert opinion and most crucially, a data-driven approach that emphasises evidence and rigorous analysis. We want to arm local decision-makers and those they work in concert with – whether that’s elected officials, bureaucratic leaders, policy advocates, neighbourhood activists, academics and researchers, entrepreneurs, or plain-old engaged citizens – with real insights and potential answers to tough problems. Subjects we cover include transportation, infrastructure, housing, urban design, public safety, the environment, the economy, and much more.

The City Monitor team is made up of some of the most experienced urban policy journalists in the world. Our managing editor is Adam Sneed, also a CityLab alum where he served as a senior associate editor. Before that he was a technology reporter at Politico. Allison Arieff is City Monitor’s senior editor. She was previously editorial director of the urban planning and policy think tank SPUR, as well as a contributing columnist for The New York Times. Staff writer Jake Blumgart most recently covered development, housing and politics for WHYY, the local public radio station in Philadelphia. And our data reporter is Alexandra Kanik, whose previous roles include data reporting for Louisville Public Media in Kentucky and PublicSource in Pittsburgh, Pennsylvania.

Our team will continue to grow in the coming weeks, and we’ll also be collaborating closely with our editorial colleagues across New Statesman Media Group. In fact, we’re launching a whole network of new publications, covering topics such as the clean energy transition, foreign direct investment, technology, banks and more. Many of these sectors will frequently overlap with our cities coverage, and a key part of our plan is make the most of the expertise that all of these newsrooms combined will bring to bear on our journalism.

Please visit citymonitor.ai going forward, where you can also sign up for our free email newsletter.


As for CityMetric, some of its archives have already been moved over to the new website, and the rest will follow not long after. If you’re looking for a favourite piece from CityMetric’s past, for a time you’ll still be able to find it here, but before long the whole archive will move over to City Monitor.

On behalf of the City Monitor team, I’m thrilled to invite you to come along for the ride at our new digs. You can follow City Monitor on LinkedIn and on Twitter. If you’re interested in learning more about the potential for a commercial partnership with City Monitor, please get in touch with our director of partnerships, Joe Maughan.

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Sommer Mathis is editor-in-chief of City Monitor.