3D steel bridge MX3D
Dutch 3D printing R&D startup MX3D has invented a 3D printing technique whereby multi-axis industrial robots are able to print strong, complex structures anywhere without needing a print bed. The multi-axis 3D printing technique works by 3D printing metal that melts, then solidifies within a second. Aided by the geometry of the overall bridge design, the strength of the metal and support from the edge of the canal and the robot, the material is able to print horizontally without bending and falling into the water due to gravity.
“We start with a piece of metal attached to the canal bank. The robots start from one side of the canal, they print their own support structure, so essentially it prints its own bridge. It stands on the floor of the bridge, 3D prints out more and keeps moving,” MX3D’s CTO Tim Geurtjens told IBTimes UK. “We have the same physics as everyone else, but it looks like it’s gravity-defying. We put a drop of metal, drop by drop at a time and it solidifies. But you could also print tubes, and then print layer over layer of tubes.”
The robot arms are similar to those used in the car industry and they can print metals and plastics from single extruders, as well as combinations of the two materials together. The 3D printed bridge project is a collaboration between MX3D, designer Joris Laarman, Autodesk, construction firm Heijmans and several other partners, including French welding specialists Air Liquide.
There could be concerns about how strong 3D printed metal is compared with traditionally welded metal but stress tests conducted by Delft University of Technology (TU Delft) proved MX3D’s 3D printed steel retains 90% of the strength of normal stainless steel. “What distinguishes our technology from traditional 3D printing methods is that we work according to the ‘Printing Outside the box’ principle. By printing with 6-axis industrial robots, we are no longer limited to a square box in which everything happens. 
Printing a functional, life-size bridge is of course the ideal way to showcase the endless possibilities of this technique.” MX3D’s CTO Tim Geurtjens told IBTimes UK. Joris Laarman, designer, added: “This bridge will show how 3D printing finally enters the world of large-scale, functional objects and sustainable materials while allowing unprecedented freedom of form. The symbolism of the bridge is a beautiful metaphor to connect the technology of the future with the old city, in a way that brings out the best of both worlds.”
