3D printers are traditionally prototyping tools. If you need to manufacture parts in large quantities or within tight tolerances, there are better alternatives. 3D printers excel at prototyping because they can switch between designs on demand and can fabricate those designs quickly without much human labor. But 3D printers are also capable of producing geometry that is difficult or impossible to achieve with other manufacturing methods. That means 3D printers are useful for creating one-off products in addition to prototypes. To prove that concept, a Dutch company called MX3D installed the world's first 3D-printed steel footbridge in Amsterdam's city center.
Queen Máxima of the Netherlands unveiled this novel new bridge on July 15th, 2021. Steel 3D printing in general is still very uncommon today and printing steel at this scale is almost unheard of. The exception is in the aerospace industry, which uses 3D printers to fabricate rockets. But this bridge bests the size of even most of those. While this is just a pedestrian footbridge, it is still massive for a 3D-printed steel structure. It is 12 meters (about 39.4 feet) long and spans the Oudezijds Achterburgwal canal, which passes through Amsterdam's Red Light District. It is open to general pedestrian traffic, so anyone in the area can traverse this first-of-its-kind bridge.
This footbridge isn't only an artistic novelty; it is also a scientific instrument. MX3D and Imperial College London researchers outfitted the bridge with a network of sophisticated sensors. Those sensors will let them gather data on how the bridge holds up to the stress of being a part of real-world infrastructure. The research team created a "digital twin" of the bridge, with is a simulated duplicate. They can feed the real-world data into that simulation to refine their models. We have accurate physical simulations for cast and extruded steel, but 3D-printed steel is still something of an unknown.
With this data, they will be able to see how the real bridge holds up compared to their predictions. That data will be invaluable for developing reliable simulations, which will improve the design of future 3D-printed structures. In the interest of progress, the collected data will be made available to researchers around the world who want to help with analysis.