Up until now everything that has been 3D printed for construction use has been done so in a lab and sent out to a job site and been assembled by humans. The makers of MX3D are on the cutting edge of autonomous 3D printing on location. These robot welders that do not look much different than those you would see on a car assembly line are being used to build a 3D printed bridge in Amsterdam.
Once programmed these robots not only print the bridge, but also the track they run on as they progress. The project is expected to start in September of 2105 and take a few months to complete. The steel bridge is a collaboration between designer Joris Laarman, software pioneer Autodesk, and many others. In order to print metal structures in mid air, the robots add a small amount of molten metal at a time, giving it time to cure before moving foward. If the project is successful it will be an amazing proof of concept and we will see this technology sooner than later in the United States.