Investigating the Effect of Fluid Flow on Chatter Vibration in Drilling

Abstract

In this work the effect of fluid flow on damping characteristics in deep drilling is investigated. Chatter suppression could be performed by both active and passive methods. Generally, passive methods are less costly; however, they require modifications in tool and machine design and structure before the operation; hence, they may not be suitable for currently running equipment. On the other hand, inducting fluid flow as a damping tool does not require any changes in the machine tool structure and could be applied only by adding an extra part (e.g. a cylinder around the drill bit as a fluid container) to the cutting setup. This container could be a flexible cylinder or a multi sliding part cylinder which surrounds the drill bit and the damping fluid and helps to suppress the chatter vibration. In this study, it was shown that conventional cutting fluids could be used as the damping agents; in fact, they could drastically improve damping characteristics of the cutting process. It was also shown that the gap between the drill bit and the cylinder does not have to be precise which lead to even cheaper construction costs. In other words, the asymptotic border of stability (ABL) would drastically rise by adding a cylinder with one to two millimeter gap around the drill bit and forcing the cutting fluid to pass through this gap.