By Leon Gettler
18 March 2014 — 3D printing has the potential to revolutionise urban sustainability. It will see houses and offices created with less waste, CO2 emissions and transport. 3D printing will make manufacturing and construction sustainable for the first time ever.
How does 3D printing work? As scientists explain here, the 3D printer can solidify object layers in several ways through ink-jet style nozzles. Most 3D printers can print with both ABS (acrylonitrile butadiene styrene), as well as a biodegradable bioplastic called PLA (polylactic acid) that is produced from organic alternatives to oil. Within a decade developments in synthetic biology are likely to make a range of biomass materials quite common. In addition to being used to produce plastic objects, material extrusion printers will produce other semi-liquid materials. The applications are already quite diverse, and include 3D printers that can print in concrete, allowing entire buildings, or large parts thereof, to be 3D printed. Building technology company D-Shape has even created an enormous 3D printer that can build objects in a form of synthetic stone.
A research group at Loughborough University in Leicestershire, in the East Midlands of England has developed a 3D printer that is able to build physical objects directly from computer-generated instructions. It has created concrete printing whereby a specific type of concrete is deposited in layers very precisely under computer control.
To date, a one-tonne reinforced concrete bench and a two-metre square “curvy” panel have been printed. It means greater precision and therefore reduced waste, and less gross CO2 emissions compared to a conventional concrete form building. Embodied energy, via transportation miles, would be lessened as printing could be undertaken in an onsite factory. Think of a skyscraper being constructed in less than a day. Although Richard Buswell, a senior lecturer at Loughborough University, says it’s more likely that the machine will be used to build components rather than a whole structure.
“I expect it will be used in high end construction, special buildings or parts of them,” he says.
The University of Southern California’s Professor Behrokh Khoshnevis has designed a giant robot that replaces construction workers with a nozzle on a gantry. It squirts out concrete and can build a 232 square metre home layer by layer in a single day according to a computer pattern.
“Each room is printed separately on site before being assembled into one house. This way the rooms can be carefully tested in a safe and easy accessible manner. Each room is different and consists of complex and tailor-made architecture and unique design features. The structure is scripted and this creates its proper strength but also generates ornament, and allows for new types of smart features, such as angled shading scripted to the exact solar angle. Each printed room consists of several parts, which are joined together as large Lego-like blocks. Both the outside façade as the interior are printed at once, in one element. Within the 3D printed walls are spares for connecting construction, cables, pipes, communication technique, wiring etc. The rooms themselves are entirely structurally sound. In the second phase of the project, the separate rooms are assembled into connected floors, and then stacked into the entire house. Added advantage is that the rooms can fairly easy be disconnected in case the house needs to be relocated.”
Then there is the concept of a robotic extruding method called contour crafting, which takes its orders from CAD software. It stores and executes the architectural designs that can be customised on a construction site even as work is underway. The machines can also automatically embed all the conduits for electrical, plumbing and airconditioning, as well as place electronic sensors to monitor the building’s temperature and health over time. Structures not only can be constructed of concrete but also of hybrid materials. For example, the outer shell of a wall can be plaster with polymer or cement filler. Steel reinforcement in the form of coils can also be added to the mix.
This has the potential to transform the construction industry. Construction is also notorious for always running over budget. Potentially, 3D printing can create precincts at a fraction of the cost with less waste and no emissions. It is also a means to reduce onsite workplace accidents.
All this sounds like science fiction and you really have to wonder how it’s possible to scale up a technology that, until now, has only been used to make relatively small objects – objects that do not demand the structural or environmental performance of a house.
But architects have told Dezeen magazine it’s closer than we think.
“When we started our research, we were dealing in science fiction,” says Gilles Retsin of Softkill Design. “Everyone on the architecture scene was saying, ‘It’s only going to be possible in 50 or 60 years.’ But when we were sitting at the table in front of one of these 3D-printing companies, these guys were like, ‘Yeah, no problem – let’s start up the research, let’s push it.’ So it’s not actually that far off any more.”
Urban planning could be transformed. The city of Louisville in Kentucky has been experimenting with 3D printing for crowd-sourced city planning. 3D printers use architectural drawings to create 1/1000 scale buildings of the city on the spot, which people can then place on a city map however they wish.
As explained in the State Tech magazine, the Vision Louisville planning initiative seeks to capture ideas about the city’s development and future from business, government, non-profits and residents.
“A public–private partnership, Vision Louisville acquired six 3D printers that it shares with the community. The printers debuted last fall at Louisville’s IdeaFestival, where they churned out structures that attendees could place on a map of the city. Today, everyone from children attending workshops at the library to city planners can use the printers, and they’ve already had a major impact. ‘Typically, we have to engage planning firms to carve foam mock-ups of a design,” says Ted Smith, director of economic growth and innovation for the Louisville Metro government. ‘3D printing will dramatically change that work and provide the opportunity to make modifications and changes very quickly and cost-effectively.’ ”
If this were adopted by urban planners around the world, it could democratise urban planning and give ordinary people the opportunity to visualise and shape their neighbourhoods.
Commentator Neale Pierce at Citiwire says 3D printing would change the world’s cities by turning them into manufacturing workshops.
“3D printing creates its final product in one process – unlike conventional manufacturing, which often demands extensive casting, forming and moulding and assembling up to thousands of parts, some from distant locations. That means products can be printed on demand, obviating large inventories or waiting for a missing part to be delivered from afar. Increasingly, today’s production and distribution of products could be de-globalised. This could spell big cutbacks in massive container ships and their ports, together with fuel-guzzling truck rigs crisscrossing continents… the carbon footprint of today’s manufacturing and transport could be reduced substantially. 3D involves dramatically reduced waste and use of toxic materials and can ease the demand for such non-renewable resources as rare earth materials.”
Still, these changes raise a number of issues. American urban planning maven Lisa Nisenson asks some key questions. The most important: are we ready for it?
“At the national scale, one can begin to consider demand decline for ports, warehouses, DHL and Amazon’s distribution centres. But what about local circulation? What happens when shipments of dolls, party favours and appliance parts are replaced by boxes of 3D printer cartridges and filament? The volume of stuff shipped will shrink dramatically, since packaging is reduced and since 3D printing uses far less material than conventional methods. How will this affect loading dock sizes, elevators and even delivery vehicle design? Will architects be able to reduce – or eliminate – loading dock space needed as smaller trucks use curbsides for deliveries?
“Localities are already sorting through the fallout of the global recession and its implications for the work force. 3D printing adds another wrinkle. Regions may no longer have to compete for big box stores as in-house manufacturing takes root, and individual companies may create new positions for 3D printing staff. But automated technology is infamous for creating fewer higher paying jobs. What kind of training programs should chambers of commerce, community colleges and local economic development corporations develop?
“Is the rush to STEM [science, technology, engineering and maths] paying enough attention to design and its role? This matters because 3D printing is only as good as the design driving the arm that squirts stuff out. Local governments are often the biggest local economic force, particularly for small and rural communities. What if they establish their own manufacturing units? What happens to vendors, distributors and suppliers who now rely on the reliable stream of business? Local governments often adopt local preference clauses after heavy lobbying by suppliers. Would the same merchants also rise up when local governments try to save money with a DIY supply chain?”