By March 2017, a team at the Oak Ridge National Laboratory plans to unveil the world’s first 3-D printed excavator, a proof of concept project intended to test the current limits of printing with metal alloys and determine the feasibility of creating heavy industrial equipment using so-called additive manufacturing — or 3-D printing — technologies.

Dubbed Project AME (Additive Manufactured Excavator), the effort is backed by the National Science Foundation and the Association of Equipment Manufacturers, and it is the latest high-profile project to demonstrate the opportunities for 3-D printing in the construction industry. Already, builders in China have unveiled a 3-D printed single family home and a six-story multifamily apartment building. Globally, sales of 3-D printers are expected to grow to $14.6 billion by 2019, according to a 2015 forecast by technology research firm Gartner.

For the construction industry, 3-D printing technology could substantially disrupt conventional building practices by offering modular construction alternatives, onsite manufacturing of building materials, and the ability to create parts, tools and even complete machines on-demand. While additive manufacturing holds the promise of reduced build times and costs, experts caution that the technology could further isolate low-skilled labor pools, threaten supply chains and require much wider recruitment of technologists and robotics specialists to the industry.  

Big printers, big costs

Regardless of Project AME’s success, the likelihood of 3-D printed heavy equipment becoming a widespread reality on job sites any time soon is remote.

Platt Boyd, the founder of Branch Technology, is focused on applying 3-D printing and robotic technologies to improve traditional building practices by minimizing rather than maximizing the use of additive manufacturing.

"There’s a lot of hype out there, but 3-D printing is not the solution for everything. It is something that is applicable in certain cases, but in most cases involving commodity construction, it is not the solution," Boyd said. "There are a lot of ways to frame and build a building that are going to be faster and cheaper than 3-D printing it."

For now, that includes manufacturing complex machinery, especially systems and equipment printed of metal alloys that require large, expensive printers. "There’s a high church of 3-D printing doing things with powder-based laser manufacturing using high performance alloys and very high resolution printers," said Joshua Pearce, an associate professor at the Michigan Tech Open Sustainability Technology Lab. "Those efforts are high-performance in every sense of the word, but the printers cost half a million dollars and have to be put in a special blast room to operate. They’re not ready for the construction site yet."

In fact, Project AME will utilize a Concept Laser machine to produce metal parts using a powder-bed-based laser melting process, and project lead Lonnie Love said in an announcement that 3-D printing of construction vehicles may not become a common practice, even among OEMs, but it could still help reduce industry costs by printing highly complex building components.

Hardware size is also a hindrance to broad-scale adoption of 3-D print capabilities in construction. Printers used in China by the Winsun Decoration Design Engineering Co. to create its demonstration apartment building, for example, were 20 feet tall, 33 feet wide and 132 feet long. The builder estimates that use of 3-D printing technologies eliminated 60% of the materials and 80% of the labor required to build the 11,840-square-foot apartment building. 

Models to help scale 3-D printing technology

Rob Schulten is vice president of Atlanta, GA,-based New South Construction, which is using 3-D print technology to create conceptual models of complex projects, including the firm’s modernization of the terminals at Hartsfield-Jackson Airport in Atlanta. "When you talk about someone 3-D printing an excavator, that’s a marketing exercise, and where we are beginning to see value in 3-D printing is not so much as a marketing tool but as a collaboration tool," he said.

A major highlight of the modernization is the construction of two canopies to cover the terminal approaches. To help steel fabricators and erectors improve their bids for the project, New South 3-D printed a scale model of the steel structure to demonstrate how it connects to the foundation of the terminal.

"This is something we see value in now as it removes a lot of the project uncertainty that can artificially increase a price," Shulten said. "It prepares our contractor team to be more successful, and if you can save just two or three days sitting around trying to figure out a problem on a project of this scale, it should translate into real dollars saved."

While New South also used virtual reality for immersive design review and project collaboration, Shulten said the tactile nature of a 3-D prototype model has advantages over VR in group settings. "When we use Oculus Rift for immersive review, one person has the headset on at a time," he said. "When you have a tactile piece that you can set in the middle of the room, conceptualization becomes more conversational, and you can get more people involved."  

Based on the success of using 3-D models for Hartsfield-Jackson Airport and other projects, New South is considering the purchase of its own printers and moving its 3-D print operations in-house. Investment into a $10,000 3-D printer would likely be offset by savings on just a handful of projects, and Shulten said the company’s virtual design team can easily manage the technology. "Even when we outsource, we’re doing most of the design for the printing company already," he said. "We send them a model that is ready to go and they just hit print."

Technology, tools and talent

New South may be privileged in that regard, as one of the primary challenges to the growth of 3-D printing in the construction industry will be finding specialists to operate the technology. Even the relatively simple creation of high-impact plastic tools requires some operator knowledge of CAD and the growth of a wider, downloadable library of product designs that has yet to be developed.

"There’s been a lot of hype about parts manufacturing that likewise hasn’t yet come to bear," Boyd said. "It is not to the point yet on small-scale 3-D printers where you don’t have to know how to model with 3-D print technologies. You have to have a skill set to operate that machine."

Instead of printing basic tools and parts on the job site, AEC professionals are likely to avail themselves to 3-D print centers and traditional suppliers as they develop 3-D print technologies. UPS recently expanded its on-demand 3-D print services to Singapore, and Home Depot has explored pilot programs with 3-D printing company MakerBot. "At some point we’re looking at the promise of going to a Home Depot and having a part or tool printed that you send them electronically," Shulten said.

Pearce agreed, but nevertheless warned that a disruptive impact to the construction industry from additive manufacturing is inevitable, and job site automation as a whole puts many job classes at risk. "We think it is flagrantly obvious how far 3-D printers are going to go, and workers need to get out ahead of what a relatively simple robot or a couple of lines of code can do," he said. "If you don’t, your job is in peril."

That the current 3-D printing zeitgeist was set into motion largely by the RepRap Project — the effort to create a 3-D printer that can print itself — offers little solace to robot-phobics concerned about the impact of automation and machine learning, even if, as Pearce attested "we're not quite to the level of Terminator-esque technologies yet."

Bearing the load

Paradoxically, 3-D printing technology and the modular, prefab construction techniques it promotes might also be an answer to the construction industry’s current labor woes. "Recruiting people into construction remains very difficult, so looking at how we can bring prefabrication to bear is an advantage," Boyd said. "Looking at building as a factory process and not an onsite process can begin to address the labor shortage that is occurring and growing in the construction industry."

Survey data compiled in August 2016 by the Associated General Contractors of America found that more than two-thirds (69%) of general contractors are finding it difficult to fill craft labor vacancies. Another 75% of respondents expect hiring woes to continue into 2017, prompting the AGC to call on the federal and state governments to boost technical training at the middle school and high school levels. 

Branch Technology, for one, will look next year to complete the first 3-D printed house in the U.S. using a combination of prefabricated, 3-D printed wall panels and components that integrate with other building systems and traditional materials. By combining robotics with 3-D print technologies, the team also hopes to get around the size constraints of large-project printers. A key to the success of that process will be developing load-bearing components that can cost-effectively be created using 3-D printing technology.

"Load bearing is one of the things we are going after and trying to validate, so we’re going through due diligence of ICC-certification testing and ASTM E72 testing on load-bearing capabilities," Boyd said. Use of a robotic arm versus a gantry printer will allow creation of components 22 feet long and 7 feet tall that can be shipped to the job site.

One thing unlikely to be found on the Branch Technology build-out will be 3-D printed heavy equipment. "Sorry to be the reality check, particularly as we are certainly vested in developing these technologies for construction, but there are still only a handful of 3-D print projects in the world that have built anything," Boyd said. "Ultimately, this is still very early stage technology."

As the Gartner forecast said, 3-D printing is likely to follow the hype-cycle of most nascent technologies, growing slowly before enjoying sudden media interest and hype about what the technology can and will do, followed by disillusionment as the reality of adoption challenges are realized, leading to the steady development of use cases and eventual global adoption.