Tool drive having a spindle shaft and operating method

Tool drive with spindle shaft for a chip-forming machining, comprising at least one electromagnetic axial actuator and a control and/or regulation apparatus for the operation of the axial actuator for changing the position of the spindle shaft along the longitudinal axis, wherein the control and/or regulation apparatus is designed to drive the axial actuator for the generation of microvibration a movement of the spindle shaft, independently of and superimposable on a feed movement, in order to affect the chip size and chip shape of the removed material, characterized in that wherein at least one axial magnetic bearing and/or one linear motor is provided as at least part of the axial actuator, and at least one magnetic prestressing apparatus is provided m order to specify a force on the spindle shaft m a specifiable direction and wherein the control and/or regulation apparatus is furthermore configured to adjust an axial micros movement of the spindle shaft, independently of and superimposed on a feed movement, in such a way as to affect the chip size and chip shape of the removed material created when drilling.