A planchet is distinguished from a simple coin blank by having a raised rim. This rim is applied to the blank by an upsetting mill, which compresses the blank's edge as it is spun between two beveled surfaces. Planchet errors encompass all mistakes resulting from a defective blank, whether or not it has passed through the upsetting mill
A clipped coin is starts as a clipped planchet; the blank before the dies in the coinage press strike it. A punching-cutting machine is used to make the planchets. Long rolled sheets of metal are automatically fed into the machine and the punching-cutting machine goes up and down, cutting circle planchets out of the thin metal strips.
If the metal is not feed into the punching-cutting machine at a steady speed, the movement of the metal does not keep up with the punching. When this happens, the machine is cutting circle planchets out of an area in the metal that has already been cut. This a curved clip.
A Rim Clipped happened on a relatively small curved clipped occurred at the rim of a coin.