US Coins

Lubrication advances extend life of dies for United States coins

Die life for circulating U.S. coins has been tripled through the use of a lubrication formula developed by U.S. Mint Materials Engineer Dr. Tony Ying.

Coin World images by Ray Wilder.

The production life of dies used to strike circulating United States coins at the Denver and Philadelphia Mints has been tripled as the result of research by Dr. Tony Ying, a materials engineer in the manufacturing division at the U.S. Mint. 

Ying's research "led to using a metal burnishing formulation that provides lubrication, corrosion inhibition, and metal protectant for the blank burnishing process."

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Ying's formula is used in the production of circulation-quality Jefferson 5-cent coins, Roosevelt dimes, America the Beautiful quarter dollars, and Presidential and Native American dollars, according to the U.S. Mint.

Ying was recognized in 2015 by the Society of Tribologists and Lubrication Engineers, receiving the society's 2015 Captain Alfred E. Hunt Memorial Award for his research.

More details on Ying's contributions to U.S. coin production can be found here.

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