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Nomex honeycomb composite core (NHC) is characterized by thin walls and complex hexagonal cells, giving it specific characteristics. However, this particularity generates significant challenges during its shaping, requiring the use of cutting tools of the particular geometry. In this study, experimental tests were conducted on the milling of NHC structure assisted by RUM technology using the UCSB cutting tool which is a toothed milling cutter. However, the experimental procedure fails to follow the cutting process, which complicates the visualization of the chip formation process due to the rapid movement of the cutting tool and the inaccessibility of the surface between the part/tool. Therefore, in order to effectively follow chip formation, a 3D numerical approach to the milling process of the NHC structure, using RUM technology, is developed using Abaqus Explicit software. On the basis of this model, the study focused on the components of the cutting force, the quality of the machined surface, and the accumulation of chips in front of the cutting tool. The numerical simulation results corroborate the experimental test findings, demonstrating the effectiveness of RUM technology in reducing cutting force components by up to 63%. An exhaustive analysis of the impact of the feed component Fy on the quality of the surface obtained was carried out, highlighting that the quality of the generated surface improves when the values of this component are low. In addition, the effectiveness of ultrasonic vibrations in reducing the accumulation of chips in front of the cutting tool is particularly accentuated, especially when large amplitudes are involved. Thus, the simulated results complemented the experimental results by offering coherent theoretical explanations. [ABSTRACT FROM AUTHOR]

Nomex honeycomb composites (NHCs) are commonly used in various industrial sectors such as aerospace and automotive sectors due to their excellent material properties. However, when machining this type of structure, problems can arise due to significant cutting forces and unwanted cell vibrations. In order to remedy these shortcomings, this study proposes to integrate RUM (rotary ultrasonic machining) technology, which consists of applying ultrasonic vibrations along the axis of rotation of the cutter. To fully understand the milling process by ultrasonic vibrations of the NHC structure, a 3D numerical finite element model is developed using Abaqus/Explicit software. The results of the comparative analysis between the components of the simulated cutting forces and those from the experiment indicate a close agreement between the developed model and the experimental results. Based on the developed numerical model, this study comprehensively analyzes the influence of the ultrasonic vibration amplitude on various aspects, such as stress distribution in the cutting zone, chip size, the quality of the machined surface and the components of the cutting force. Ultimately, the results demonstrate that the application of ultrasonic vibrations leads to a reduction of up to 50% in the components of the cutting force, as well as an improvement in the quality of the machined surface and a reduction in the size of chips. [ABSTRACT FROM AUTHOR]

Machining of Nomex honeycomb composite (NHC) structures is of critical importance in manufacturing parts to the specifications required in the aerospace industry. However, the special characteristics of the Nomex honeycomb structure, including its composite nature and complex geometry, require a specific machining approach to avoid cutting defects and ensure optimal surface quality. To overcome this problem, this research suggests the adoption of RUM technology, which involves the application of ultrasonic vibrations following the axis of revolution of the UCK cutting tool. To achieve this objective, a three-dimensional finite element numerical model of Nomex honeycomb structure machining is developed with the Abaqus/Explicit software, 2017 version. Based on this model, this research examines the impact of vibration amplitude on the machinability of this kind of structure, including cutting force components, stress and strain distribution, and surface quality as well as the size of the chips. In conclusion, the results highlight that the use of ultrasonic vibrations results in an important reduction in the components of the cutting force by up to 42%, improves the quality of the surface, and decreases the size of the chips. [ABSTRACT FROM AUTHOR]

The manufacture of aluminum honeycomb structures is a major concern for companies in the aerospace industry, due to its out-of-plane high strength and stiffness-to-weight ratio. However, the shaping of this type of structure represents a technical challenge for engineers and researchers in terms of premature wear of the cutting tool and the quality of the machined surface. Generally, machining studies are based on experimental tests. Nevertheless, the experimental procedure fails to follow the mechanism of chip formation due to high rotational speeds of the cutting tool. To this end, it is necessary to use robust and reliable numerical models to access instantaneous and much localized physical quantities. For this purpose, we have developed a 3D finite element model associated with real working conditions using the Abaqus/Explicit analysis software. Based on this model, an experimental validation was carried out by analyzing the appropriate behavior laws. Furthermore, the influence of the geometry of the cutting tool in terms of the number of teeth on the size of the chips, the cutting forces, and the quality of the generated surface was analyzed. The obtained results show that the integrity of the cutting tool can be optimized and the quality of the machined surface can be improved. [ABSTRACT FROM AUTHOR]

Aluminum honeycomb structures have been frequently used in many industrial applications, especially in aerospace and aeronautics, due to their high strength and stiffness to weight ratio. The machining quality of aluminum honeycomb structures is generally related to plastic deformation of the walls forming the honeycomb structure and burrs. Consequently, the use of this type of structure requires specific machining operations and special tools. In order to carry out in-depth studies on the milling of aluminum honeycombs, a 3D finite element model was developed with the help of Abaqus/Explicit software. The model thus developed is validated with several experimental tests and for different machining conditions. Based on the developed model, the relationship between the cutting forces and the friction coefficient between the cutting tool and the honeycomb during the cutting process is studied. The main objective of this work is to highlight the effect of physical and geometrical parameters during the milling of aluminum honeycomb structures on cutting forces, surface quality generated, chip size, and material accumulation in front of the cutting tool. The comparison between the simulated results and the experimental results indicates that the developed numerical model is in good agreement with the experimental reality. [ABSTRACT FROM AUTHOR]