Chip Morphology and Delamination Characterization for Vibration-Assisted Drilling of Carbon Fiber-Reinforced Polymer

Ramy Hussein,Mohamed Elbestawi,M Attia,Ahmad Sadek

doi:10.3390/jmmp3010023

Abstract

Carbon fiber-reinforced polymers (CFRP) are widely used in the aerospace industry. A new generation of aircraft is being built using CFRP for up to 50% of their total weight, to achieve higher performance. Exit delamination and surface integrity are significant challenges reported during conventional drilling. Exit delamination influences the mechanical properties of machined parts and, consequently, reduces fatigue life. Vibration-assisted drilling (VAD) has much potential to overcome these challenges. This study is aimed at investigating exit delamination and geometrical accuracy during VAD at both low- and high-frequency ranges. The kinematics of VAD are used to investigate the relationship between the input parameters (cutting speed, feed, vibration frequency, and amplitude) and the uncut chip thickness. Exit delamination and geometrical accuracy are then evaluated in terms of mechanical and thermal load. The results show a 31% reduction in cutting temperature, as well as a significant enhancement in exit delamination, by using the VAD technology.

Highlights

Lightweight materials such as carbon fiber-reinforced polymers (CFRP), titanium, and aluminum alloys are widely used in the aerospace industry, typically representing, collectively, more than 75% of the total weight of new-generation aircraft [1,2,3]
Entry and exit delamination is a typical surface integrity defect resulting from conventional drilling [8,9,10,11]
This study aims to investigate the effects of LF-Vibration-assisted drilling (VAD) and High-frequency vibration-assisted drilling (HF-VAD), for a wide range of machining parameters, on the thrust force, cutting temperature, and delamination factor

Summary

Introduction

Lightweight materials such as carbon fiber-reinforced polymers (CFRP), titanium, and aluminum alloys are widely used in the aerospace industry, typically representing, collectively, more than 75% of the total weight of new-generation aircraft [1,2,3]. High strength-to-weight ratio, high stiffness, superior corrosion resistance, and near net shape capabilities are significant advantages of using CFRP [4,5]. These capabilities result in significant enhancement of performance, operation and maintenance costs, and environmental impact. Entry and exit delamination is a typical surface integrity defect resulting from conventional drilling [8,9,10,11]. Delamination damage deteriorates the mechanical properties of the machined part and reduces in-service life due to fatigue [12,13]. Higher cutting speeds with lower feed were recommended to reduce mechanical and thermal damage [17,18]

Objectives

Methods

Results