A 3D printed bridge under construction in Amsterdam shows how 3D printing finally enters the world of large-scale, functional objects and sustainable materials while allowing unprecedented freedom of form.
The functional bridge, which is currently being crafted in a warehouse, will be installed across the Oudezijds Achterburgwal canal. And, the project is the work of MX3D, a design company that utilizes 3D printing for furniture.
In an early experiment, a used industrial robot was equipped with an extruder head that pushed out a two-part polyurethane resin that hardens in seconds. The method is accelerated by the use of two $10 paint strippers. The robot arm gave the system six degrees of freedom rather than the three degrees afforded by traditional 3D printers. As a result, build volume is only limited by the length of the robot’s arm.
The experiments led to a process using a standard MIG welder that deposits weld wire instead of plastic. Stainless steel is used for this project with a maximum deposition rate of three to four kilograms per hour. To build the canal-spanning structure, four IRB 2600 robots, on loan from ABB Robotics, will be used to produce the 500 million to 1 billion separate welds it will take to complete the bridge.
MX3D customized the robots with special nozzles and a set of sensors that enable them to closely monitor of the welding process, as well as a custom base that allows them to walk over the portion of the bridge they just created. The position of the robot is determined within the coordinate space of the CAD model, either by triangulated laser range finders or an external laser scanner that images the entire structure.
The completed bridge will span 9 meters and will be about 2.5 meters wide, weighing in at about 5,000 kilograms.
>> Read more by Sheri Kasprzak, Product Design & Development, November/December 2016