Analysis of dynamic characteristics of micro-drills

Micro-drills were modeled as long twisted beams. Models for the critical speeds and the critical buckling loads were developed based on the finite element method of analysis. The effects of transverse shear, rotary inertia and gyroscopic moments were included in this analysis. The models have the capability of analyzing a wide variety of geometrical cross-sections. A computer program was developed for the calculation of the variations of the critical speeds and of the buckling loads. The effects of drill geometry, boundary condition, rotational speed, and cross-sectional area on the buckling loads and the critical speeds were analyzed.