What is sheet metal punching?

Punching means that with tools that have a certain shape, the material is pressed against an underlying corresponding die, whereby a hole or a molding is made in the material. Both punch and die are ground so that they form the right shape. Sheet punching is suitable for sheet metal up to a maximum of 2 – 4 mm thick material. There are usually several different tools in the machine that are programmed according to CAD files.

You can read more about punching here.