One-shot drilling of unconventional thin metal hybrid stacks for aerospace applications

Abstract

Abstract. The aerospace industry's relentless pursuit of lighter, stronger, and more fuel-efficient aircraft has led to the widespread use of lightweight materials, particularly aluminum alloys, in aerospace engineering. This study focuses on the challenges associated with one-shot drilling without back-up forces of thin parts, a strategy aimed at reducing cycle, avoiding part separation for cleaning after drilling, and minimizing part assembly problems. Despite its effectiveness, problems persist with defects developing at the interface due to the interlayer gap phenomenon. This gap causes metal chips to accumulate and is influenced by both process parameters and the clamping conditions and methodologies. While existing literature primarily associates process parameters with burr measurements, this study delves into the often-overlooked influence of clamping strategies on the occurrence of interface defects. Through experimental drilling on a thin stack of Al7075-T6 and Al2024-T3, various clamping schemes were analyzed to assess their impact on burr height. The results were also correlated with the drill verse, thrust force, and torque. The objective is to increase know-how about these aspects and optimize clamping strategies for effective one-shot drilling, addressing gaps in current research.