Metal Joints Could Scale Construction 3D Printing in New European Project

We´re all very familiar with 3D printing concrete for buildings and formwork, but there is much more potential out there. The Politecnico di Milano is looking at reducing construction waste and energy usage though 3D printing to popularize steel additive manufacturing (AM) for construction. Under the ConstructAdd umbrella, the Politecnico will unite with the following companies and organizations to achieve its goals, including the 3D printing of metal joints:

• Italian metal powders company MIMETE
• VALLOUREC, a large manufacturer of rolled steel tubes
• CIMOLAI, a maker of large steel structures such as bridge components
• Det Norske Veritas (better known as DNV), a standardization and classification body that also performs assurance, especially in maritime, oil and gas.
• Manufacturer of tube bending and cutting machines, BLM Group
• Prima Industrie, a laser marking firm that previously launched a 3D printing subsidiary called Prima Additive
• ArcelorMittal Vitry, one of the largest steel producers
• Research groups IMDEA Materials Institute in Madrid, the University of Pisa, and RWTH Aachen

Dr. Alper Kanyilimaz is an assistant professor in the Department of Architecture, Built Environment and Construction Engineering at the Politecnico di Milano, described the project this way:

“The main objective of ConstructAdd is to bring metal 3D printing technology into the mainstream of the construction and automotive industries. Why? Because the current objectives of governments worldwide, and society as a whole, are reducing carbon emissions and dealing with waste problems. These concerns, which are major challenges for the construction industry in particular, cannot easily be solved with conventional techniques, simply because conventional techniques were invented for problems of the past. Given around one-third of all the waste produced around the world each year comes from the construction industry, steel production has a major role to play here. The current manufacturing techniques available are not easily optimized, and there is a lot of material wasted. For example, during the cutting and welding of steel plates. Also, using conventional construction techniques, a lot of material is used where it isn’t needed and placed in unnecessary spots.”

His team hopes to 3D print on-demand, on-site, custom joints and other fastening components. This would save energy and reduce material waste. Now, of course, we can be skeptical here and look at this as a sop to established industries. Over the years, the steel sector, in particular, has received more than its fair share of group hugs from government.

In this case, however, the collected consortium looks like it could combine some valuable skills. The aims include: the selection of two wire and two powder feedstocks; defining standards for recycling, safety, and mechanical properties; examining how companies could use these processes to make EN1090-compliant parts, and performing life cycle analysis. A lot of the research looks very specifically at optimizing joint structures which would be more than welcomed given their prevalence.

The consortium will be examining laser powder bed fusion, which at first glance looks very expensive for this application, but could be used to make façade elements and connectors that would enable the quick production of larger components with custom geometries. The team will also be exploring wire arc additive manufacturing (WAAM) and laser directed energy deposition (LDED), which seem like much better candidates for large scale construction.

Current concrete 3D printing is also limited in its ability to construct multistory buildings and steel reinforcement of some kind would be welcome. The use of 3D printed steel joints and fasteners would be a more efficient way to build large, multi-story structures. This is especially interesting in Europe. Because construction workers are aging, laborers are generally hard to find and the continent wants to make a concerted move towards an energy transition. The consortium hopes that its technology can be used in automotive, as well. It is easy to see how a welded tube structure could be a good base unit for a house construction, as well as a frame for a car.

The consortium hopes to generate less carbon, use less material and use less energy. In terms of carbon and waste, the construction industry is especially environmentally detrimental, producing around one third of all waste on the planet. More pre-built and steel components built on-site steel could also require considerably less concrete, which could further reduce emissions.

The team could make what is essentially a custom tube welding and bending robot, which might be comparatively boring, but could lead to the cost effective construction of very large and strong structures. These might, in turn,  be used for facades, walls, lightweight frames, and buildings. New WAAM and LDED units from BLM and Prima would be welcome additions to the market, but less revolutionary. To me using tubes would be the quickest way to large scale structures. 3D printing: it’s a series of tubes?