THE FIRST 3D-PRINTED STEEL BRIDGE

ROBOTS ARMED WITH MIG WELDERS are completing construction of the first 3D-printed stainless-steel bridge. The Netherlands-based design company behind the bridge, MX3D, specialises in large-scale 3D printing, making custom furniture, art and industrial tools. It launched the project in 2015 to push the possibilities of 3D fabrication in construction and architecture, says MX3D chief technology officer Tim Geurtjens. The robot 3D printers were developed out of necessity after MX3D couldn’t buy printers capable of building bigger objects. So the firm outfitted a standard automotive assembly robot with a MIG welder and then wrote software to turn it into an additive printer. “A MIG welder melts stainless-steel wire on a layer. It’s strong and homogeneous and, if you keep adding wire, that’s 3D printing,” says Geurtjens. The 12-metre pedestrian walkway will be installed in Amsterdam’s red light district after several months of stress testing. Once installed, sensors on the bridge will report back to MX3D, creating a digital mirror of the bridge to monitor flex, vibrations and foot traffic.