How Coins Are Minted

The processes involved in coin production can be broken down into three main parts: producing the blanks, creating the coinage tools and striking the coins.



Production of blanks

Blanking is the process of producing coin blanks, which will then be minted. Metal sheets are fed through a press, which punches out blank round discs of metal. In the case of numismatic coins, precious metals such as silver are used to create the coin blanks. These blanks go through a meticulous polishing process prior to minting.



Creation of coinage tools

Circulation coins are produced to meet day-to-day cash transactions. Numismatic coins, on the other hand, are issued for the purpose of commemorating significant national events and to cater to collectors’ interests. These coins, being legal tender, should be dignified and not degrade the country's currency. Hence, the coin themes are carefully reviewed before the coin design artist finalises the design artwork. Once the coin themes are finalised and approved, the details of the artwork designs are replicated on a plaster mould at several times the diameter of the intended coin by a sculptor/engraver. The design is subsequently duplicated from the plaster mould using special silicon rubber material, to form a rubber mould.

Finally, the design is reproduced onto an epoxy mould. The epoxy mould is examined for imperfections to detect for flaws at this stage. Following this, the epoxy mould goes through a curing process to strengthen it. This process requires optimum precision since a mould that is too soft would be too weak, and one that is too hard would be brittle.


Next, the master dies are produced in the pantograph process. The designs on the epoxy mould will be reduced and “traced” onto the master die, which bears the same diameter as the coins to be minted. The master die is a critical coinage tool, as it is used to reproduce many working dies that is to be used during coin production.

     

Working dies are created in an extremely high pressure squeezing process called hobbing. These working dies are then heat-treated and polished prior to the coin striking process.


   

Minting of coin blanks

The minting process follows by having the designs of the working dies struck onto the blanks, turning them into coins.


 
   



Last Modified on 26/11/2016