How does one manufacture a congressional gold medal?

U.S. Mint demonstrates the production process
By , Coin World
Published : 05/18/15
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Further details provided by the U.S. Mint follow. 

The authorizing legislation determines the number and type of medals to be produced. The die production process and medal production are all executed at the Philadelphia Mint.

Once final obverse and reverse designs are selected by the Treasury secretary or official designee, sculpts are created either digitally or by hand in plaster through successive casting steps.

If the sculpt is made by hand, an additional step is taken to scan the plaster model and convert it into digital 3D data.

Next, the digital models go through an engineering analysis to set height of relief and address detail particulars to promote good metal flow (coinability) without effecting the fidelity of detail in the sculpt.

The final digital 3D models are sent to the CNC (Computerized Numerical Control) department where comprehensive calculations (millions of them) are performed on the complex 3D models to generate the NC cutter paths required to CNC mill the dies.

Finally, 3-inch dies are milled for the obverse and reverse. Milling times range from 24 to 36 hours depending on design complexity.

Only dies are manufactured for the 3-inch congressional gold medals. No hubbing or other tooling is involved.

From start to finish, about two to three weeks of engineering time are generally required to turn around a 3-inch congressional gold medal, including one week to test and strike an approved gold medal.

Depending on the complexity of the design, a sculpt can take an additional two weeks to produce, according to Mint officials.

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