Sustainable construction typically refers to using renewable and recyclable materials when building new structures, as well as introducing new methods and technologies that help reduce energy consumption and waste. The main objective of sustainable construction is to limit the construction industry’s impact on the environment.
The Bovay Civil Infrastructure Laboratory Complex at Cornell University is home to a 6000 lb industrial robot arm that has the capacity to 3D print large-scale construction components.
Theoretically, this is a more sustainable construction method as many processes and waste products associated with conventional construction techniques are eliminated when it comes to using robots with 3D printing capabilities.
Scaling Additive Manufacturing
3D printing – also known as additive manufacturing – has the potential to facilitate faster and more accurate construction of complex or bespoke items in addition to lowering labor costs and producing less waste. It could also allow construction to be undertaken in unorthodox or potentially dangerous environments not readily accessible to a traditional human workforce.
Additive manufacturing has a long-established history, documenting back to the early 1980s, and has already led to significant advances in fields such as medicine, robotics, aerospace and the automotive industry as well as finding a use for prototyping in manufacturing processes. While, in theory, additive manufacturing can be used in construction projects, there are still question surrounding the scalability of the method.
This is where the strengths of Cornell’s Bovay Complex come into play, as the laboratory is equipped for large-scale projects and able to test the viability of a range of materials and structures for use in 3D printed construction.
The scaling of many of the phenomena controlling the build processes are such that they need to be studied at a scale near to that in which they will be used. The same applies to some of the phenomena controlling performance. Plus, there are always the unknown surprises that occur when up-scaling early-on with a new technology.
Derek Warner, Professor of Civil and Environmental Engineering at Cornell University
IRB 6650S Industrial Robot
The 3D printing robotic system, which is largely comprised of the IRB 6650S industrial robot, will offer researchers first-hand access to robotic construction methods and additive manufacturing processes. Cornell is among a small collective of institutions to have this technology on site, which also gives students hands-on experience with the developments in the fast-paced industry of construction.
IRB 6650S is a six-axis robot with a 12-foot-reach that has been installed on a track spanning 12 feet; this gives it a possible construction area of around 8 x 30 feet. This is a relatively large 3D printing area considering molds are not required for constructing components.
The robotic arm is extremely versatile and can even be modified beyond 3D printing applications with the potential to introduce welding and laser systems. While labor costs and intensities are reduced compared to traditional methods, operating the system still requires a team effort. One group needs to mix a batch of mortar that will be the right consistency to flow through the nozzle without clogging, while another group operates the robot to control how much mixture flows through.
The consistency of the mortar is one of the main challenges, as being too thin or thick will cause problems either way.
The bottom layers need to be rigid enough to hold the next layer that’s being printed. But they can’t be so rigid that when you print the next layer on top, it doesn’t stick to it.
James Strait, Manager of Tech Services for the Boyay Lab
“You need to make the adhesion in there, but you can’t have it so soft that it squishes out,” Strait continued.
The team is currently working on a way to fabricate a new nozzle that would improve upon the current process, which is now only capable of printing aggregate up to 4 mm. A new nozzle would be able to withstand heavier loads and therefore facilitate the construction of larger, stronger components.
Sriramya Nair, assistant professor of civil and environmental engineering, will be using the system in a forthcoming class, “Sustainability and Automation: The Future of the Construction industry,” to introduce students to new technologies and potential challenges they may face in the real world.
Nair is also aiming to develop a mixture to print with in the future, rather than being dependent on the manufacturer’s premixed materials.
The carbon footprint of these materials is very high right now… So that’s another goal, to reduce the carbon footprint associated with 3D-printed materials.
Sriramya Nair, Assistant Professor of Civil and Environmental Engineering
References and Further Reading
Nutt, D., (2022) 3D-printing robot enables sustainable construction - CornellCast. [online] CornellCast. Available at: https://www.cornell.edu/video/3d-printing-robot-enables-sustainable-construction