Modal interactions for spindle, holders, and tools
Tony L. Schmitz
Abstract
This paper describes the interaction between vibration modes associated with the machine-spindle and those associated with the holder-tool when the holder-tool combination is inserted in the milling machine spindle. It is shown that when the bending natural frequency of the holder-tool is near a machine-spindle natural frequency, there is a combined two mode frequency response (similar to a dynamic absorber) for the assembly that exhibits increased dynamic stiffness over those situations when the interaction is absent. Experimental results are provided. The variation in tool point frequency response with tool extension length is then used to calculate the corresponding stability maps. These maps are evaluated to determine the effect of interactions between machine-spindle and holder-tool modes on milling stability. Conclusions are presented.