Modeling the orientation-dependent dynamics of machine tools with gimbal heads

Machine tools with gimbal heads continuously rotate and/or pivot their spindle heads to maintain the required relationship between the tool and the surface being cut. This results in orientation-dependent dynamic behavior at the tool-center-point, which further results in orientation-dependent machining stability of the system, potentially limiting productivity during continuous cutting. A dynamic substructuring procedure is proposed to model this behavior by orienting machine tool substructures to their proper configuration prior to synthesis to obtain the synthesized orientation-dependent response. Influence of the changing dynamics on chatter stability is further investigated; and, a strong dependence of machining stability on orientation is observed.