The technology of 3D printing of buildings was established in 1941!

3D printing of buildings is currently one of the most dynamically growing areas of additive technology – more companies in the world are acquiring multi-million rounds of financing for the development of their manufacturing techniques, while boasting about unique projects. It can be said that 3D printing in construction industry is another great step in the development of additive methods, which will push the entire industry in a completely new direction. Meanwhile, it turns out that 3D printing of buildings is not only nothing new, but also its origins date back to World War II! The first 3D printing method of concrete was patented in the first half of the 1940s, which to some extent questions even the achievements of the official “father of 3D printing” – Charles Hull, who patented stereolithography “only” 40 years later!

To write that this matter is “nothing new” is a big understatement. In 1941, the American inventor William E. Urschel developed and patented a machine for “building walls”. The patent was granted in January 1944 and expired in January 1961 – thus this manufacturing method is generally available in the public domain. Just over half a year ago, a video presenting this project appeared on the Jarett Gross channel – a YouTuber specializing in documenting achievements in the field of 3D printing of buildings, along with a number of archival films by Urschel presenting the use of his machine in practice. This topic is currently a “hit” on LinkedIn, thanks to Omar Geneida, who posted the same video there, triggering a long discussion about it.

Urschel created a company operating under his name, which is now a large enterprise that produces specialized machines for cutting or grinding food and has no contact with either 3D printing or construction. In the first half of the twentieth century, in the 10s, 20s, 30s and 40s, he applied for a patent for a whole bunch of inventions related to food processing – technological solutions for peeling, cutting, dicing, slicing fruit and vegetables. At the same time – by the way, he worked on other machines – including a layer-by-layer wall-building machine, which is nowadays referred to as 3D printing.

Source: https://patents.google.com/patent/US2339892A/en

The idea behind this invention is relatively simple – although limited as to the shape of the structure being built. In the middle of the building, an arm is installed that moves cyclically in a circle. At the end of the arm there is a concrete application device with a mechanism for aligning the side walls and inserting metal wire reinforcement.

Ceoncrete must be fed manually – machine operators add it to the hopper as the work progresses.

Due to the specific structure of the machine, the walls are built in a circle, creating something like an igloo.

What distinguishes this method from today’s methods is the almost perfect quality of the walls being built, the edges of which are evened at the level of applying subsequent layers of concrete. What’s more, applying them at a slight angle does not cause the structure to collapse and allows you to create quite steeply inclined arches.

Holes in walls – for windows or doors, are either cut out of still-dry concrete or put on the formwork.

Importantly – the machine is controlled manually – there is no code or computer control. At the time when the first computers were being developed, they were still in the development phase…

The whole process can be seen in the video below by Jarett Gross. For my part, I would like to add that while browsing Urschel’s patents, I came across this one: US2314468A – “Machine for forming and applying cohesive plastics”. It is an invention that extends the concept of a wall-building machine, where concrete is replaced with plastic. It can therefore be said to be an early concept of what we now call FDM technology, developed in 1989-1990 by the Scott and Lisa Crump couple who founded Stratasys – today one of the two largest additive manufacturing companies in the world.