Abstract: The dynamic model of a drill in drilling process was
proposed and investigated in this study. To assure a good drilling quality, the vibration variation on the drill tips during high speed
drilling is needed to be investigated. A pre-twisted beam is used to
simulate the drill. The moving Winkler-Type elastic foundation is used to characterize the tip boundary variation in drilling. Due to the
variation of the drill depth, a time dependent dynamic model for the drill is proposed. Results simulated from this proposed model indicate that an abrupt natural frequencies drop are experienced as the drill tip
tough the workpiece, and a severe vibration is induced. The effects of parameters, e.g. drilling speed, depth, drill size and thrust force on the
drill tip responses studied.
Abstract: For smaller mechatronic device, especially for micro
Electronic system, a micro machining is a must. However, most
investigations on vibration of a mill have been limited to the
traditional type mill. In this article, vibration and dynamic
characteristics of a micro mill were investigated in this study. The
trend towards higher precision manufacturing technology requires
producing miniaturized components. To improve micro-milled
product quality, obtain a higher production rate and avoid milling
breakage, the dynamic characteristics of micro milling must be
studied. A stepped pre-twisted mill is used to simulate the micro mill.
The finite element analysis is employed in this work. The flute length
and diameter effects of the micro mill are considered. It is clear that
the effects of micro mill shape parameters on vibration in a micro mill
are significant.