Abrasive flow machine, method for ascertaining material removal on a workpiece, and method for determining the cutting power of a grinding medium

An abrasive flow machine for moving abrasive media over a surface of a workpiece and/or through the opening of a workpiece, comprising

• a media drive device which is adapted to move the abrasive medium over a surface of a workpiece and/or through the opening of the workpiece in a flow direction;
• a workpiece holder for mounting the workpiece, having two parts adapted to be positioned on opposite sides of the workpiece;
• a structure-borne sound sensor for measuring structure-borne sound generated in a workpiece when the latter is machined with an abrasive medium;
• and
• an electronic evaluation unit on which software is stored which is configured such that the evaluation unit is configured to receive a raw signal of the structure-borne sound sensor and by means of the software to process the raw signal of the structure-borne sound sensor to determine a continuous value of the root mean square of the structure-borne sound measured by the structure-borne sound sensor over time and to integrate the root mean square of the structure-borne sound, wherein the evaluation unit is adapted to infer a cutting power of the abrasive medium and/or a rate of material removal on the workpiece, wherein the cutting power and/or material removal rate is evaluated based on the integrated measurand that is formed by the evaluation unit over the continuous value of the root mean square of the structure-borne sound measured by the structure-borne sound sensor over time,
• wherein the integrated measurand of the root mean square of the structure-borne sound measured by the structure-borne sound sensor over time is specific to a particular material removal, and
• wherein the material removal rate is calculated by dividing the value of the material removal by the machining time and/or the cutting power is ascertained by dividing the material removal by the media flow rate and
• wherein the media drive device is further configured to change a flow velocity, fluid pressure, or back pressure of the abrasive medium based upon the material removal rate.