Microendmill dynamics including the actual fluted geometry and setup errors - Part II: Model validation and application

This paper presents a study to validate the microendmill dynamics model derived in Part I. A laser Doppler vibrometer system that is coupled with a microscope is used to measure the natural frequencies and mode shapes of nonrotating microendmills with different geometries. Free-free boundary conditions are obtained by suspending the microendmills using elastic bands. The dynamic excitation is delivered through miniature piezoelectric elements attached to the microendmill shanks. In each case, the model is compared to experimental results and solid-element finite-element (FE) models. To evaluate the model in the presence of rotational effects, the model is compared to an FE model. In most cases, the model was seen to capture the dynamic behavior of microendmills accurately. The validated model is used to investigate the effects of microendmill geometry, and radial and tilt runouts on the modal behavior of microendmills. Furthermore, possible geometric simplifications to fluted region are evaluated based on the accuracy of the predicted natural frequencies of the microendmills.