Dry Drilling: Feasibility of Aluminium Alloy Stack Material in Aerospace Structures

Abstract

The aerospace industry drills millions of holes annually on stacked airframe structures. Unfortunately, as the drill breaks through cutting fluid is sprayed on the machining environment and workshop. The scientific challenge is to develop a viable and cost effective drilling process that can operate without cutting fluids. Development of dry drilling processes will enable the aerospace industry to substantial improve the machining environment and addressing the health and safety issues for their workers. The main purposes of this study is to determine the effectiveness of coating capability, effect of machining parameters and influence of swapping the position of stacked materials on the cutting performance and quality of holes drilled. Successful baseline experiments employing various cutting parameters and tool coating were conducted and showed promising results. Trials indicated CVD diamond-coated drills produce remarkable higher thrust compared to other coatings. However, regardless of coating used, most severe deviations of diameters were captured at lower feed and speed. In term of surface roughness, results have pointed out that Standard MoST seem to be the promising coatings in reducing the hole surface roughness.