Computer Simulation of Self-Excited and Forced Vibrations in the External Cylindrical Plunge Grinding Process

The vibrations that deteriorate the workpiece surface in external cylindrical plunge grinding operations are studied by time domain simulation. Both forced vibrations caused by the eccentricity of grinding wheel, and self-excited vibrations are modeled. The results show that lobes are developed on the circumferences of workpiece and grinding wheel under the workpiece regenerative chatter conditions. The lobes are observed to grow exponentially, and they precess on the wheel and workpiece. The chatter frequency is found to be equal to the number of lobes times axis speed minus the precession frequency. Its value is always higher than the system’s natural frequency. It is also found that modulation of chatter amplitude is due to grinding wheel forced vibration. Furthermore, form accuracy of the workpiece is shown to be closely related to forced vibration. Grinding conditions to reduce the effects of forced vibration on the cylindrical plunge grinding operation are recommended.