Sometimes problems aren’t visible to the naked eye … or even your standard microscope. In 2006, Dr. Tony Ying, a material engineer at the U.S. Mint in Washington D.C., and a team of nano-mechanical scientists at the National Institute of Standards and Technology set out to find a solution to a very tiny problem.
Now, that solution saves the U.S. Mint roughly $2 million per year.
In part three of Federal News Radio’s special report, Rainmakers and Money Savers, we take an inside look at how innovative federal employees can outdo their own salaries in savings when they team up and take initiative.
Mint, NIST pair up
“If you want to make a beautiful coin, first you have to make a beautiful blank,” Ying said.
A blank is a faceless coin. It becomes the coin we recognize after it is struck by a pair of die. An average die for a dime used to last about 100,000 to 150,000 strikes. That was a short life in Ying’s mind. The dies seemed to wear out and crack, or break rather quickly. He wanted to know why.
In 2006, Ying started looking at the lifespan of coin dies and began to generate a research database.
Ying took his research to NIST. There, he met up with a former colleague, Dr. Richard Gates, who heads the Nanomechanical Properties Group at NIST. Ying worked at NIST when he was studying for his PhD, and he knew Gates, a nanotribologist, had the resources he needed.
“Tribology is just the study of rubbing and, in more practical terms, it’s the study of processes like friction, wear and lubrication,” Gates said. “If you think of what nano might mean, the width of a human hair is about fifty microns and that’s about 50,000 nanometers. So, nano is just really, really small. So nanotribology is the study of friction, wear and lubrication on a very small scale, and it’s basically what happens on the surface of a coin during minting. And it’s one of the processes that we studied to try to understand what was going on.”
The Mint had the coins and the problem to solve, but NIST had the right equipment and the environment.
Finding the culprit
At NIST, the Nanomechanical Properties Group has a special facility where Gates said it was possible to make the mechanical and dimensional measurements at the very small scales they needed for this project. He said the lab is buried 12 meters underground for low vibration and described the clean-room environment as a place with filtered air and scientists in “bunny-suits.”
“We’re doing research on such a small scale that dust particles can have an adverse effect on some of the research we’re doing,” Gates said.
Ying was especially interested in using the Fourier Transform Infrared Spectroscopy (FTIR). The machine is found in many labs, but the one at NIST measures down to the atomic layer.
“Basically, you’re using infrared light, and you’re shining it off the coin, and the light gets absorbed by chemicals that are on the surface. And by determining the frequency of the absorption from the chemical, you can tell what chemicals are on the surface,” Gates said. “It also discovered a way of calibrating this process to look at certain bonds that are there. So, we were able to determine not only the presence of certain chemicals or chemical bonds but also how thick the layer was that was built up. And that was important to the whole process of controlling that process and actually minting in the coins.”
Once they were able to look at everything in the lab, the proof was in the pudding. They began to hone in on the lubricant as the culprit for premature wear and compromise of the dies. But it wasn’t just texture. As it turned out, the key to solving the Mint’s issue was controlling the amount of lubricant.
(Watch the video below to learn more about the design and production of coins. Story continues after the video.)
“In some ways, it’s like a three bears problem — Goldilocks and the Three Bears. If you have too little lubricant, you have problems; you get too much lubricant, you get problems. If you have just the right amount, then you can get successful lubrication. That’s what we ended up developing, basically a monomolecular — a very thin controlled amount of lubricant — that was just enough to strike a coin and allow the die life to increase,” Gates said.
And increase it did. The tedious work paid off. Die life has more than doubled since they changed the lubrication process. The Mint is saving roughly $2 million per year in the cost of equipment, and time and labor spent replacing the dies. The Mint is still tracking die life in the database, so it knows right away when something goes amiss.
Just last year, the Mint saw a drop in the die life at the Philadelphia Mint. Ying said they were able to pinpoint the problem immediately as a defective pump. Without the ongoing database, the problem could have easily gone undetected.
Collaborating to save money
These days, scientists and engineers are operating on smaller budgets along with the rest of the government. Feds attend fewer conferences and have to be more creative when it comes to finding opportunities to network across their fields of discipline. But Gates said that collaboration is how these money-saving ideas are born.
“These kinds of fields are very multidisciplinary. It relies on not just one aspect of chemistry or physics or something like that, but material science and all sorts of engineering aspects that are brought in, and it’s very hard to get all of [that expertise] yourself,” Gates said. “What you tend to find is that when you’re facing some sort of a problem, you need to go and seek other people’s guidance and expertise. So that’s an important area in tribology.”
Ying said the wealth of information available at NIST was key to his work at the Mint.
“There’s a lot of smart people who are willing to help you. It’s a nice environment to be in. Certainly the budget climate has been pared back … but scientists are fairly resourceful, and we try to find cheaper ways to do it, and get out there and interface with people. … It’s a critical aspect of being a scientist,” Gates said.
It took about four years of research and development before the two organizations arrived at a solution for the lubricant at the Mint. Now, they see the fruit of that labor every month as they monitor the die life database and the savings in their bottom line.
“Any improvement starts with an idea and, in this case, I think you have to really recognize the concept that Tony envisioned and how he carried it through,” said Richard Robidoux, division chief of engineering for the U.S. Mint. “It required that he consider a lot of different chemicals or elements that might be used as lubricants, but worked to find ones that would create an atomic-level bond, which would make the uniform but very thin layer that would provide the lubrication. So, it did take a lot of thought and creativity on his part to achieve that and it wasn’t just a matter of taking certain ones off the shelf and trying them until we found one that worked. He actually had to develop the chemical.”
Dr. Ying and Dr. Gate’s work on applying nanotribology in the coining industry was published and can be found here.