Abstract
Recently, the requirement for micro-hole machining is increasing, such as a fuel injection nozzle for cars, a nozzle for chemical-analysis machines, and a through hole of printed circuit board. Although the drilling mechanism has been studied, the centripetal action in micro-drilling has not been examined completely. Therefore, Relationship between the centripetal action and the orientation of the drill using a simulation software has been studied. As a result, it became clear that the difference in the moving resistance related to the drill orientation affects the centripetal action.