An investigation of the dynamic absorber effect in high-speed machining

In order to achieve increased material removal rates in high-speed machining, stable cutting conditions may be selected based on the system dynamics. In this paper, we apply Receptance Coupling Substructure Analysis to develop models for a stacked flexure setup and a spindle-holder-tool assembly in order to investigate the 'dynamic absorber effect' that can improve the system dynamic stiffness and, therefore, increase the critical stability limit in machining. The dynamic absorber effect results from an interaction between modes associated with the individual substructures, e.g. the spindle-holder and tool in the spindle-holder-tool assembly. Experimental results are provided for: (1) a two degree-of-freedom stacked flexure assembly; and (2) a machining center. These results can be considered in the selection of assembly parameters, such as tool overhang length, as well as in the design of spindle, holder, and tool components in order to improve dynamic stiffness and, consequently, material removal rates.