Tool/Material Interferences Sensibility to Process and Tool Parameters in Vibration-Assisted Drilling

Abstract

Vibration-assisted drilling is a critical process applied on high-value products such as aeronautic parts. This process performs discontinuous cutting and improves the drilling behavior of some materials, including chip evacuation, heat generation, mean cutting force. Several research papers illustrated the differences between vibration-assisted and conventional drilling, hence demonstrating that conventional drilling models may not apply. In this process, the cutting conditions evolve drastically along the trajectory and the tool radius. The tool/material interferences (back-cutting and indentation) proved to significantly contribute to the thrust force. A method properly describing all rigid interferences is detailed. A local analysis of the influence of the tool geometry and process parameters over interferences is presented. Interferences distribution on the tool surfaces are highlighted, and the presence of back-cutting far away from the cutting edge is confirmed. A comparison is performed in conventional drilling between the predicted shape of the interferences on the tool surfaces and the real shape of a used tool. The most interfering areas of the tool surfaces are slightly altered to simulate a tool grind, the interference results are compared with the original tool geometry, and significant interference reduction is observed.