Tool Neck Geometry Design to Improve Stiffness of Micro Endmills

Due to the scaling effect, micro endmills have low stiffness in nature, which will result in lose of form accuracy in workpiece and vibration of micro tools during micromilling process. Through analytical modeling, it is found that the neck geometry of the micro endmill has a big influence on the tool stiffness; therefore it is important to improve the neck shape to achieve a high stiffness. In this paper, five different types of neck geometries were studied first by mathematical models, and then tested by Finite Element Method (FEM) to see their influence on the tool performance. Based on the modeling results, the micro endmill geometry was re-designed; micro endmills with new geometries were manufactured and tested in experiments. The experimental results showed that the new neck geometry has higher stiffness compared with the neck geometry used in commercial endmills