Investigating damage mechanisms of honeycomb cores machined with PCD circular saw blades

Abstract

Aluminum honeycomb core (AHC) is extensively applied in aerospace and transportation industries for its exceptional strength-to-weight ratio. However, the unique structure of AHCs limits their manufacture. In this research, the damage mechanism of AHCs is firstly studied with polycrystalline diamond (PCD) circular saw blades to provide high-quality AHCs for wide-format honeycomb composites. The study meticulously examines the various forms of sawing damage incurred by AHCs at different material removal rates (MRR) and categorizes them accordingly. The results show that burrs of AHCs change from tiny blocks to larger strips with the MRR. At high MRR, the predominant failure modes include collapse, deformation, and hot cracking, while at low MRR, AHCs mainly suffer from cracking, micro-collapse, and oxidation by SEM and EDS analysis. A dynamic analytical model of the sawing angle is proposed based on the sawing trajectory to elucidate vibration scratching and burr formation. The effect of the sawing angle is quantified by the deformation displacement and damage area by the optical measurement. The microscopic reciprocating vibration scratching of AHCs is interpreted by the blade’s vibration state. The causes of sawing damage at different MRRs are investigated, indicating that at high MRR, the increased impact of the sawtooth leads to severe vibration scratches, collapses, and strip burrs, whereas, at low MRR, the high-frequency scratching of the sawtooth tends to result in tearing and micro-collapses. A comprehensive description of burr formation is presented by a 3D finite element model. Additionally, the cutting heat is the main cause of the oxidation of sawing surfaces by EDS. This systematic investigation analyzes and explores the sawing damage mechanisms of AHCs, offering in-depth insights for optimizing the sawing process to eliminate surface quality problems and improve the sawing efficiency and accuracy of wide-format AHCs.