Drives' stiffness of 5-axis machine designs: Evaluation and comparison by Schur complement eigenvalues.

Stiffness features of three widespread designs of the CNC 5-axis machine tools with a fixed column are investigated: the design with the double-tilting spindle head, with the tilting head and swivel workpiece table, and with the tilt-swivel workpiece table. For this purpose, a new approach presenting a straightforward adaptation of the known robotics method is developed: Schur complement eigenvalues of the stiffness matrix of the machine drives' system are applied to the machine stiffness evaluation. The stiffness-related performance indices of the considered designs are defined and compared. [ABSTRACT FROM AUTHOR]