Substructure Coupling of Micro-End Mills

Micro-end milling is an important micro-manufacturing technique which offers the ability to machine micro parts of complex geometry relatively quickly when compared with photolithographic techniques. Key to good surface quality in the micro milling operation is the minimization of tool chatter. This requires an understanding of the system dynamics; the system including both the milling tool and the milling structure. However, owing to the miniature nature of micro end mills whose diameters are as small as 50 micrometers, impact hammer testing cannot be applied directly to predict the dynamics at the tool tip. This paper investigates substructure coupling of the spindle/micro machine and arbitrary micro tools with different geometries. This is done through use of the receptance coupling technique. The frequency response functions (FRFs) of the spindle/micro machine are experimentally measured through impact hammer testing utilizing a laser displacement gauge. The dynamics of an arbitrary tool substructure are determined through modal finite element (FE) analyses. Joint rotational dynamics are indirectly determined through experimentally measuring FRFs of gauge tools. The method also enables designers to come up with the optimum design of tool geometries prior to actual fabrication to prevent chatter vibrations.Copyright © 2006 by ASME