Mobile Foundry for Tomorrow's Army
Whenever Army troops stationed around the world move from one site to another, a great deal of waste material can be left behind. Everything from rubber and plastics to scrap metal have to either to be dealt with by the local community or incinerated in a massive and potentially hazardous open burn pit. But a research team from the AFS community is exploring the concept of a mobile foundry, where replacement parts could potentially be cast on the battlefield using just about any scrap metal that’s on hand––operating inside a fully-equipped shipping container that’s approximately 12 x 18 ft.
The work is funded with a grant that’s part of the Strategic Environmental Research and Development Program (SERDP), a cooperative between the Department of Defense, the Department of Energy and the Environmental Protection Agency that seeks ways to improve processes that support objectives of all three government bodies.
Under the direction of the Army Research Laboratory (ARL), metalcasting experts at Worcester Polytechnic Institute have made long strides toward making the idea a future reality. Dr. Diran Apelian, director of the Advanced Casting Research Center (ACRC), was principal investigator of the research at Worcester Polytechnic Institute in Worcester, Massachusetts, before relocating both the ACRC and himself to University of California Irvine about six months ago. Apelian continues the work with a team of colleagues at WPI as provost and professor emeritus; he recently participated in an annual review presentation to a military panel, providing a thorough status of the team’s achievements to date.
Apelian joined Casting Source on an early morning call at the end of April to share some details.
Question: Why do you think a mobile foundry is an important concept for the U.S. military?
Apelian: The Army has a lot of people all over the world; they’re in the field or someplace in the desert, God knows where. And they’ve got a piece of equipment that maybe was made in 1970, or ’60, or ’50, and not a lot of spare parts. And things break down and need to be repaired. And you’re not going to wait for Amazon Prime to deliver parts to you. You’ve got to make it right there on the spot. So that’s where the concept of the mobile foundry came from really.
They envision that we need a foundry on the spot in one of those containers that you just drop anywhere. And in it, you would be able to melt the metal, pour it and make the part.
The other thing is, there’s so much scrap. And the idea is to capture all this scrap metal and make something out of it that has value. You create value out of nothing.
Question: Scrap could be almost anything, and you can’t just mix random metals together in a casting. How would they know what they’ve got and what to do with it?
Apelian: That’s right, you need to know what you’ve got, and then you can do something with it. The first part of our project is sorting the scrap. With certain technologies that were developed in the recycling center we founded at WPI 12 years ago, we have techniques where we can identify what it is, and as I said, if you know what you’ve got, then you can blend [the metals] and put them together so that you have the right composition for a casting. These would include laser-induced breakdown spectroscopy––LIBS––or X-ray fluorescence or X-ray transmission. It’s not visual but you determine and identify the input from the metal chemistry.
It’s like cooking in the kitchen––you’ve got all the ingredients, you put them together and make the soup, right? That’s what the sortation part of the project is, and it obviously satisfies the Environmental Protection Agency’s objective with the whole idea of recycling and recovery.
Once you have the ingredients––the input materials sorted––then it’s just a matter of melting, and that you can easily do. It just requires some power and an induction furnace.
Question: So, you’ve checked the boxes on sorting and melting––how about the mold-making and the casting method? What has the team determined as the best way to create the molds in which to pour their now-identified and melted metal?
Apelian: If I need a part on the spot for my tank or whatever it is for defense, I don’t have weeks to wait for shipments to come in. If I need to have it the next day or so, then, using the CAD file––a drawing of the part from a database inventory––with additive manufacturing, I can make a wax pattern of that part.
You create a positive image in three dimension out of wax, and investment casting lends itself to this mobile foundry where, using additive manufacturing, essentially, you’ve got the pattern made, the shape of the mold made, and using shell technology utilized in investment casting, you can create that mold fairly easily.
Now, you’ve got the scrap materials sorted, you know what your ingredients are, you’ve got the right composition, you melt it, and then you’ve got this mold that you made through additive manufacturing, you pour and make your part.
Question: As the equipment and processes for this efficient mobile foundry come together, could this model be commercialized and potentially replace metal casting as we know it?
Apelian: Absolutely not. There’s a scaling issue––you’re not going to be able to make parts that are 50 feet long and 10 feet wide. This is for small replacement parts, so it’s not going to replace traditional metal casting.
But will it be a very convenient, pragmatic and very much needed technology in the field for the soldier? Yes. There’s a need for it. But technologies had to be developed. The sorting technology had to be optimized. The steel metallurgy had to be optimized as well as the investment casting process in order to be able to make it quickly and efficiently and effectively.
Question: Who are the other key people on the team?
Apelian: First, there’s Jianyu Liang––she’s a metallurgist and a scientist who had worked at Aberdeen [Army Proving Ground, Aberdeen, Maryland] on a sabbatical, so they knew her. She is a great collaborator. When I retired at WPI, Jianyu became the principal investigator; the best way to serve the “customer,” the SERDP, was to have continuity of the project without any disruptions. In today’s world we work virtually no matter where we are and seamlessly, just like a mobile foundry should work!
There are two other colleagues who are tremendous resources: One is Rick Sisson, an expert in steel metallurgy, particularly the heat treating of steel. And the other is Brajendra Mishra, who became the director of the recycling center after I left WPI. He was the co-director of our Recycling Center at Colorado School of Mines, but six years ago or so, we “recycled” Brajendra to WPI. He now heads the department of Materials and Manufacturing and is an expert in recycling. Before joining academia, Brajendra was at Tata Steel.
This is a seamless group and we work well together. Needless to say, we have students working on this project, who will graduate and will be making their contributions to industry.
Question: How would you describe the current status as well as projected completion of the SERDP research project?
Apelian: All the three pieces we discussed have been proven and validated; the technology has been fine-tuned. And the questions that we had at the beginning, whether it’s doable or not, all those issues have been attended to––so we’re in the last leg of the project.
Because of COVID, not much happened last year, because you have to be in the lab to work, right? So, we got a no-cost extension ... essentially, we have another year to finish this project. Now, we are working on system integration. Putting it all together. And this will be the year where that will happen. And once that’s done, we turn it over to the ARL.
Question: The science of metalcasting isn’t something you just learn overnight––if the mobile foundry were to someday become a reality in the Army, how do you think the personnel operating it could or should be trained?
Apelian: This is where AFS comes in––there probably should be some introductions to the folks who are involved in Aberdeen and ARL with AFS because, to me, the training and education is one of the first steps. I’m thinking to myself, you can have all the technology in the world, but you still have to have people who understand it.
It’s all about metal casting, it’s all about controlling the liquid-solid transformation, at a different, smaller scale. The need to educate and train people is always the universal constant. If you think education is expensive try ignorance; the cost of the latter to society is even more expensive. CS