Large Scale Additive Manufacturing and Concrete 3D Printing Technology

In late 2018, two robots worked together to 3D print an elegantly curving concrete truss. These bulky robots overcame one of the main problems with “3D concrete” and other Large Scale Additive Manufacturing (LSAM) techniques: How can we build structures that are bigger than robotic arms can handle?

The creators of this robotic duo at Nanyang Technical University in Singapore call the process “swarm printing.” When most people think of robotic swarms, drone armies come to mind. But most potential uses are not military.

Indeed, architectural futurists have proposed flying construction robots to build lofty, biologically inspired structures. But in the near future, the most likely robotic candidates for this type of construction work will be terrestrial.

Are there advantages to a robotic swarm other than building large structures? We can think of at least three. First, swarms can build topology optimization structures that are hard to manufacture. These structures, such as the airplane wing modeled and partially 3D printed at the Technical University of Denmark, have fractal-like internal components and resemble biological structures.

Second, the process of topology optimization could be â€œgamified” to entice players to find the best, most beautiful structures for swarms to build. For example, players could look at possible ways to build a particular bridge and find subsets that are especially elegant and strong. They could then rerun the topology optimization simulations with altered parameters and find even more elegant solutions, thereby “winning” that particular round of the game.

Third, robotic swarms specially adapted to operate in austere environments could be useful responses to natural and manmade disasters. One reason is the speed at which they could perform needed manufacturing tasks such as structural reinforcement of a failing dam, construction of housing for displaced people, or rapid repair to a damaged road system. This, combined with their potential to reduce the number of humans working in dangerous conditions, make a robot swarm an ideal choice to work among the “first responders” in these types of situations.

To be sure, there are many hurdles to overcome before swarm printing becomes feasible, acceptable, and attractive as a construction method. For example, keeping each robot in sync spatially with other robots will be challenging. In addition, relative to typical 3D concrete printers, small robots would presumably waste more energy driving back and forth from the source of concrete to the site of printing. This would likely raise costs relative to large 3D concrete printers, which have already printed entire houses for only $4,000. If current trends in the field continue, these are technical challenges will likely be solved in the near future. However, there are also societal concerns to overcome.

Does swarm printing represent yet another way that robots are taking over jobs from humans? Will construction workers be put out of work by the widespread adoption of swarm construction? The answer to both questions is almost certainly “Yes.”

It is worth remembering that the introduction of steam power that drove the Industrial Revolution, the assembly line revolution in the early 20th century, and the computer revolution of recent decades, just to cite a few examples, all prompted alarm about lost jobs. In each case, the new technology vastly increased human employment opportunities rather than diminishing them.

Someone will need to design the robots, someone will need to build the robots, someone will need to service the robots and when required, someone will need to repair the robots. The companies and organizations that lead the way in this new field will be among the leaders of the next “revolution.”

(The views expressed in this piece are the authors’ own and do not represent the official views of the Navy or the Department of Defense.)