Under regenerative effect or rattling is understood when machining with machine tools, the swing of the tool by self-excited vibration. It occurs in many machining processes, such as turning or milling .
Vibrations are generated when machine tools are operated . These vibrations are divided into self-excited vibrations and externally excited vibrations. The regenerative effect is one of the self-excited vibrations and causes the machine to vibrate close to the machine's natural frequency and a waveform that approximately corresponds to the natural waveform.
When a tool comes into contact with the workpiece for the first time , an impulse or impact causes the machine to vibrate and, as the tool is now engaged, a ripple occurs on the machined surface. After a certain running time, the so-called dead time, this waviness returns to the cutting zone and generates a new pulse. This leads to a renewed excitation of the machine, so that again ripples appear on the surface. If the system damping is insufficient to calm this process, the machining process is unstable.
A measure of the instability is the cutting width at which the transition from the stable to the unstable machining process takes place.