A Solid Foundation: 3D Printing for Construction By Arlene Lo
Skilled-labor shortages and low productivity trouble the construction industry, especially in developed countries. Despite rising wages, there are 347,000 vacant construction jobs as of June 2019 in the US alone. Over the last two decades, the construction industry has an average growth in labor-productivity of 1 percent per year globally. In contrast, the annual growth figures in labor-productivity for the manufacturing sector and the total world economy are 3.6 and 2.8 percent respectively. Can 3D printing for construction provide a solution? This automated building method promises 24/7 operation and a significant reduction in both construction times and onsite workforce. Avoiding waste and using recycled materials, 3D printing also paves the way to sustainable construction. I asked Henrik Lund-Nielsen, CEO of COBOD and 3D Printhuset, to shed light on whether 3D printing will become a standard feature in the construction industry. 3D printing is long established in making architectural models, molds, and building components. As early as 1999, Foster + Partners were producing SLA models for the skyscraper commonly known as the Gherkin in London. In a more recent commercial real-estate project, Skanska 3D printed cladding â€˜shroudsâ€™ for the canopy of an office rooftop terrace. However, additive manufacturing is mainly applied in the
early phases of the construction pipeline, such as design rather than the actual construction phase. Most attribute this to the viability of the machinery and the slow incorporation into building codes.
Concrete problems and solutions Lund-Nielsen says construction 3D printing companies can be separated into two groups. The focus of most construction 3D printing firms is getting their first printer ready. This involves enhancing the speed and precision of printers and commercializing the product. To this date, only COBOD, CyBee and XtreeE manage to sell construction 3D printers regularly. For these industry leaders, it is more about getting the rest of the supply chain to follow suit. While a print head speed of one meter per second is possible, COBOD has yet to find 3D printable materials that can keep up. Currently, available materials limit the speed to 10 - 30 centimeters per second. To fully utilize the maximum building rate 3.6 cubic meters of concrete, weighing a total of 10 tons would need to be supplied per hour. This means equipment such as silos, mixers, hoses, and pumps would be vital in containing and delivering such a load. Also, concrete needs to set quicker. Concrete suppliers are geared towards
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