ON THE EFFECTS OF VARIATIONS IN THE DESIGN PARAMETERS ON THE DYNAMIC PERFORMANCE OF MACHINE-TOOL SPINDLE-BEARING SYSTEMS

An analysis is presented of the dynamic characteristics of machine tool spindle-bearing systems subjected to harmonic excitation at the spindle nose. The method utilizes the influence coefficient method and is validated using Maxwell's reciprocity theorem. The calculation compares natural frequencies and mode shapes of the continuous system and its replacement by a discrete lumped mass system. The parameters considered in the study include bearing stiffness, position of the drive pulley, mass of the workpiece, optimum position for introduction of damping, and the number of steps of the spindle between the bearings. The optimization criterion is the dynamic flexural stiffness of the spindle nose taking into the account the natural frequencies of the system with their corresponding mode shapes. The results are presented in dimensionless form to ensure their general applicability. In the final portion of the paper the results are compared with a finite element study and experimental validation reported elsewhere in the literature. © 1990.