Many internal contours cannot be produced with a single punch in a single operation. However, it is possible to produce them using what is called the nibbling process. In this case, a punch, normally circular, is moved along the desired edge in several passes. In this way, even less common contours can be produced without additional tooling costs.

However, it should be pointed out that the nibbled edge is notably rougher and more uneven. It is recommended to use this technology only up to sheet thicknesses S of 4 mm for mild steel and 3 mm for stainless steel. Depending on the machine and the tool, it is also possible to use thicker sheets.