What Is A Coin Planchet ?

A coin planchet is a prepared disc-shaped metal blank onto which the devices of a coin image are struck or pressed. The metal disc is called a blank until the time it passes through the upsetting machine which causes the rim to be raised. Once it has a rim, the disc is called a planchet. 

Thomas cup 2000

This is the planchet of one Ringgit Thomas Cup 2000 commemorative coin with Bi-metal material; ring composition is Nickel-Brass and center composition is Copper-Nickel material. Weight is 8.15gm with diameter 26.5mm and thickness 2.33mm.

When referring to ancient coins, and coins which were made from cast metal discs rather than machined metal discs, the generally preferred term is flan.

The distinction is very clear: the disk is a "blank" before getting the rim, and a "planchet" is a blank that has gone through the process of  upsetting mill to form the rim.

In order to protect the coin design in everyday use the rim of the coin is lightly raised. With a view to facilitating the material flow under the pressure of the two coining dies, as the blanks leave the cutting press they are given an upsetting operation which produces a rim. Rim diameter and rim profile are exactly adapted to fit the coining tools. After the rimming operation the blanks are annealed and then are ready for striking. The anealing operation is controlled to give a uniformly low hardness without coarse grain formation as this is important for a perfect strike. However, even after an excellent bright-annealing, which can nowadays be applied, the blanks are not still suited for mass coinage. They must first be subjected to a four stage surface treatment.

The stages are cleaning by washing (possibly pickling), wet burnishing, the application of lubricants and preservatives, and finally drying and dry polishing.


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