Influence of Workpiece Imbalance on Regenerative and Frictional Grinding Chatters

This paper investigates regenerative and frictional grinding chatters affected by mass eccentricity in the workpiece. Time delays and velocity-soften friction coefficient are employed to represent regenerative and Stribeck effects in normal and tangential grinding forces. Eigenvalue calculation and continuation scheme are used to find stability boundaries for both regenerative and frictional instabilities, illustrating that a deep grinding enhances the regenerative stability but impairs the frictional one. Near each kind of boundaries, numerical simulations and bifurcation analyses are adopted to present various chatter motions in the grinding, either with or without mass eccentricity. It is found that the frictional chatter is prone to be quenched by the external excitation due to the mass eccentricity. On the contrary, the regenerative instability still persists, but is perturbed to be quasi-periodic.