Printing Buildings: No, Not Drawings—Buildings

Although the trend today for many 3D printer manufacturers is focusing on creating smaller, more budget friendly machines—units small enough to fit on your desktop—that’s not the case at Monolite UK (d-shape.com), which has developed a printing technology capable of printing large structures. It uses binding materials that harden sand into a stone-like resin. The technology, known as “D-Shape,” may one day be capable of printing full-scale buildings.

Not yet a commercial product, the lone D-Shape printer resides in an Italian warehouse and looks like a thrill ride you might see at an amusement park. It offers a print area of 6 x 6 meters. There’s a T-shaped metal printer head that slides on a horizontal track and rises up vertical metal pillars as it builds the structure. Three hundred nozzles that distribute the binder decorate the printing head.

The technology was created after four years of research and development by Italian engineer Enrico Dini. Dini’s goal was to create a fast, yet energy- and cost-efficient process to create freeform construction scale objects that architects could study to gauge the impact of final construction, rather than the miniature maquettes they’ve long used.

“At the moment, there is nothing similar that could print solid, monolithic stone-like structures on such a scale straight from one digital file,” says Andrea Morgante, an architect who helped experiment with an early prototype of the technology in 2008. Morgante was challenged by Dini to create a structure that would test the capabilities of D-Shape. He came up with “Radiolaria,” a gazebo-type of open structure set to be built in Pontedera, Italy, sometime in 2010. The Radiolaria model was printed at about two meters in height, about one fourth-scale. It took two weeks to print and then another week to hand finish. But that was two years ago on an early prototype of the machine. Today’s D-Shape can print structures in a matter of hours. Complete solidification takes about a day.

D-Shape works similarly to most other 3D printers. The process starts with a CAD file of the design, which is then translated into STL file format. This controls the build of the part. Printing begins as the machine deposits a 5 to 10-mm layer of sand onto the print bed. The printer head runs over that area and deposits the inorganic binder (a magnesium-based glue) in the required area. The procedure continues, layer by layer. The sand that doesn’t have binder applied to it acts as the structural support and the object is built. It is then removed so that the end result is a fully printed 3D structure, done without concrete and internal support steels. No molding frameworks, cages, scaffolding and manpower. “In this respect, D-Shape’s technology is quite unique and revolutionary,” Morgante says.

“It’s difficult to see the limit of this technology, at this early stage,” claims Gianluca Miele, a D-Shape spokesman. After all, it’s not everyday that someone sets out to develop 3D printers large enough to take on such tasks. But Miele notes, there would be several benefits if the technology eventually catches on in the construction industry as a replacement to brick or concrete:
•    The sand and glue binder are both abundant and inexpensive. (It cost just 60 Euros, or about $80, for the materials used to create Radiolaria.)
•    “It can be broken, but it’s solid like stone,” Miele says, noting that the hardened structure exhibits compression and tensile numbers similar to concrete.
•    Unlike pouring concrete, D-Shape isn’t a high-energy, high-carbon-emitting process. And it’s estimated to be four times as fast at one-third of the costs.
•    After the printed structure has served as a model or is an unappealing result, the material can be reduced back to its powder state to be used again, like a life-like blueprint that doesn’t have to get thrown away.
•    The machine can be disassembled and reassembled for on-site printing.

Miele isn’t ruling anything out in regard to D-Shape’s future. “We are now moving only the first step in a new direction,” he says. Perhaps it could print exterior home walls, replacing the tedious brick-laying process? It may be used to print furniture, backyard storage sheds, or even act as a complete substitute to concrete, possibly to form basements. Miele said the European Space Agency (ESA) has even showed interest in the printer, perhaps to use lunar dust as a construction material to build structures on the moon.

Who knew 3D printing might take us out of this world?