3D printing a car is impressive enough; building an excavator, layer by layer, is downright unimaginable. Researchers at Oak Ridge National Laboratory (ORNL) have not only imagined it, they plan to execute it next spring at ConExpo/Con-Agg in Las Vegas with a live demonstration.
Some off-highway companies took notice of what ORNL did with Cincinnati Inc. and Local Motors on the 3D-printed car (see http://articles.sae.org/13841/) and wanted to go bigger, Lonnie Love, group leader for manufacturing systems research and corporate fellow at ORNL, explained to Off-Highway Engineering. “They wanted to do something similar in terms of demonstrating something grand that could get people excited about where additive manufacturing and construction is going. That was the catalyst for pursuing this vision of printing an excavator at ConExpo.”
ORNL is teaming with several organizations to bring this vision to reality. Key partners on the 3D-printed excavator project include the Association of Equipment Manufacturers, the National Fluid Power Association, the Center for Compact and Efficient Fluid Power and the National Science Foundation. OEMs like Case New Holland and universities, including the University of Minnesota, are also contributing to the project, which is supported by the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy – Advanced Manufacturing Office.
At the Manufacturing Demonstration Facility at ORNL, about 15 people, consisting of material scientists, engineers and mathematicians, are working on the project. “We have a core group that’s looking at the next generation of large-scale 3D printers. A lot of work has gone on in terms of polymers and composites; now we’re going toward large-scale metal,” Love said.
There are three elements of the 3D-printed excavator, each created through different additive processes: a composite cab using Cincinnati’s Big Area Additive Manufacturing (BAAM) system, a metal heat exchanger manufactured using the Concept Laser powder bed system, and a metal boom born of a large-scale metal printer that’s still under development with Wolf Robotics.
“So in one demonstration, you really get a strong glimpse of where the technology’s going,” he said.
“We’re going to try to print out a heat exchanger that will actually be functional and shows the limits of what you can do with additive in terms of increasing the [exchanger’s] efficiency as well as making it lighter and smaller,” said Love. The laser system enables very fine detail and high accuracy.
The biggest part and the most challenging, according to Love, will be the boom. The plan is to have the Wolf robotic system “growing” large metal parts at a fairly high rate within nine months. “I’ve been at Oak Ridge for about 20 years and this is by far, for me personally, the biggest challenge my team has tackled. It’s a big leap, but I have full confidence in the team including all of the industrial partners,” he said.
The printer will be smaller than the BAAM polymer system, which in terms of build volume is 8-ft wide, 6-ft tall and 20-ft long. The Wolf metal printer will be in the range of 4 x 4 x 10 ft, Love said.
ORNL is trying to overcome factors that have traditionally hindered the progress of metal printers—namely size, speed and cost of materials. “With metal printers, we’re primarily making things that are about a cubic foot in volume at rates of about one cubic inch of material grown per hour,” Love explained. “So to make something the size of a coffee cup will take you all day. And the materials are generally very expensive, hundreds of dollars a pound. That really is restrictive. So we’re trying to use low-cost feedstock steel that’s about a dollar per pound and trying to grow parts at relatively high rates—hundreds to thousands of cubic inches an hour. If you do that, then it starts to become compelling in terms of using additive for things like excavators.”
Off-highway industries such as construction, with its relatively low volumes especially compared to passenger vehicles, is in the range where additive can be a powerful tool, if the technology progresses the way Love and others at ORNL envision.
“That’s part of our focus at Oak Ridge,” said Love, “how to enable these technologies to open up capabilities that are attractive for industries that, up until today, haven’t been interested.”