I have a solution to India’s housing shortage – print new ones! The reader might think I am writing of a new accounting trick – a variant of Quantitative Easing where the government prints money. How can they print a house? Well, I am talking of the upsurge in the popularity and scope of 3-D printing. This technique has been around in the laboratory since the 1980s. But it has only been an increasingly viable process from the 2000s when new materials, ink jets and curing ovens have become available.
Object printing is, in fact, a radically new idea given that the manufacturing processes that mankind has used for eons is subtractive – like finding a log, striping off wood to make a hull shape on the outside, and then hollowing out the inside to make a canoe. This applies across most traditional manufacturing modes, which rely on the removal of material by methods such as cutting or drilling (subtractive processes) as well as hammering to size.
The printing process is additive, with new layers of materials being squirted onto old layers to build up a shape. It is a very versatile method allowing hollow sections to be programmed using a weak material that is later dissolved or melted away. The printed shapes do not require much after-finishing: certainly not compared to the casting of metal, then whipping it into shape with massive hammers, and afterwards cutting and drilling.
Of course, both subtractive and additive processes lead to assembly in a traditional way. Engineers find printing is a super way to reduce stockholdings of spares: when called for, simply print a new one! Now that is a way of printing money. The cost of holding stocks – many of which are obsolescent and can all become obsolete – is reduced, allowing the capital to be put to better uses.
In India, housing shortages were computed in 2007: there was a shortfall of some 20 million homes. A study in 2012 added together the number of homeless people, the number of homes that are older than 80 years, and the number of homes that are 40 to 80 years old and in poor condition. That totalled 18.8 million.
India has a great need to mobilise rebuilding quickly as its homelessness reduction over five years is perceived as too slow, and its labour force is on the move, shifting to the cities. 3D printing has rapidly become well-established across many manufacturing sectors, from prosthetics (even as detailed as copying bone structures), through all high-tech industries to aerospace with its requirements for strength and low weight in ever-larger single structures (when the traditional subtractive methods are found to be very, very costly).
This increase of scale stimulated researchers at the University of Southern California to consider spraying thin films of concrete to build walls. Essentially they are doing little more than replacing old traditional manual methods with robot-guided sprays and trowels. The thin films dry quickly, don’t have hidden structure-weakening cavities and the surface finish is good.
And, just like the smaller scale 3D printing, the computer-controlled robotics can spray complex shapes, even with “holes” for doors, windows and pipework. All in all, this process is very fast and yields a superior product.
I think there is very good potential to marry the research in California with venture capital in India to satisfy India’s housing needs. As commercial experience is gained, this housing will meet the high sustainability regulations imposed upon modern buildings which must emit a minuscule thermal image. By applying insulating materials at the same time as the concrete, buildings can be made for both cold and hot climes guaranteeing their heating demands are minimized – the aim is to create a mass market of negative carbon homes.
Of course such rapid building does not remove the cities’ responsibility to create a built environment fit for modern living – with good sanitation, roads, shops, medical and entertainment centres as well as carrying good mass-transport links to work and more distant places. Planners and do-ers are both needed in abundance.
But, above all, India needs a bold vision if it is to nurture its citizens. I think 3D printing of houses looks to be a really good idea: an idea that might get lost in the fervour of the forthcoming elections. I hope not – the people deserve the best.
The writer is founder and chairman of Horasis, a global visions community.
Horasis is a global visions community committed to enact visions for a sustainable future. (http://www.horasis.org)
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