Apparatus and method for monitoring a manufacturing process for making a through hole

The present invention relates to a method for monitoring a manufacturing process for making a through hole, in particular by means of spark erosion, comprising the steps of: detecting actual values ​​of structure-borne sound, which is generated during processing, and determining of an aperture and / or a completion of the through-hole based the recorded actual values ​​of the impact sound. Furthermore, the invention relates to a device for monitoring a manufacturing process for making a through-hole.