Improving Coolant Effectiveness through Drill Design Optimization in Gundrilling

International Conference on Aerospace and Mechanical Engineering 2017

航空航天工程;机械制造

Woon, K.S.^1 ; Tnay, G.L.^2 ; Rahman, M.^1

Department of Mechanical Engineering, National University of Singapore, Singapore, Singapore^1

Machining Technology, Singapore Institute of Manufacturing Technology, Singapore, Singapore^2

关键词: Commercial design;    Coolant applications;    Coolant channel;    Design optimization;    Hole configuration;    Thermo mechanical failures;    Transport behaviour;    Vertical drop test;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/370/1/012025/pdf
DOI  :  10.1088/1757-899X/370/1/012025

学科分类：航空航天科学

来源: IOP

【 摘 要 】

Effective coolant application is essential to prevent thermo-mechanical failures of gun drills. This paper presents a novel study that enhances coolant effectiveness in evacuating chips from the cutting zone using a computational fluid dynamic (CFD) method. Drag coefficients and transport behaviour over a wide range of Reynold numbers were first established through a series of vertical drop tests. With these, a CFD model was then developed and calibrated with a set of horizontal drilling tests. Using this CFD model, critical drill geometries that lead to poor chip evacuation including the nose grind contour, coolant hole configuration and shoulder dub-off angle in commercial gun drills are identified. From this study, a new design that consists a 20° inner edge, 15° outer edge, 0° shoulder dub-off and kidney-shaped coolant channel is proposed and experimentally proven to be more superior than all other commercial designs.