This paper deals with the characterization of friction during drilling of a titanium alloy. After a review on friction models in drilling, a sensitivity study to sliding speed, contact pressure, lubrication and tool coatings is presented. A dedicated tribometer has been used and highlighted that titanium is significantly influenced by sliding velocity and contact pressure, whereas lubrication and coating have a minimal effect on friction. The paper then questions whether friction is similar on a drill’s rake/flank faces and on its margins. It is pointed out that tribological conditions on the margins are completely different compared to the ones on the rake and flank faces. Whereas friction on both rake and flank faces is considered as an open tribosystem, friction on the margins corresponds to a closed tribosystem configuration. It is shown that there is a large variation in friction between both tribosystems, and that the closed tribosystem on the margins leads to a significant drift over time. Finally, this paper shows that modelling of friction around a drill is complex and necessitates the separate study of both the rake/flank faces and the margins.

本文研究钛合金钻孔过程中的摩擦特性。在回顾了钻井中的摩擦模型后，提出了对滑动速度，接触压力，润滑和工具涂层的敏感性研究。使用了专用的摩擦计，并强调了钛受滑动速度和接触压力的影响很大，而润滑和涂层对摩擦的影响却很小。然后，论文质疑钻头的前刀面/后刀面及其边缘的摩擦力是否相似。要指出的是，与前刀面和后刀面相比，边缘的摩擦条件完全不同。前刀面和后刀面的摩擦都被视为开放式摩擦系统，而边沿上的摩擦则对应于封闭式摩擦系统配置。结果表明，两个摩擦系统之间的摩擦都有很大的变化，并且边缘上的闭合摩擦系统会导致随时间的明显漂移。最后，本文表明，钻头周围的摩擦建模很复杂，需要分别研究前刀面/后刀面和刀刃。