Papers by Keyword: Nanomachining

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Authors: N. Atiqah, I.H. Jaafar, Mohammad Yeakub Ali, B. Asfana
Abstract: Fabrication of micro and nanoscale components are in high demand for various applications in diversified fields that include automotive, electronics, communication and medicine. Focused ion beam (FIB) machining is one of the techniques for microfabrication of micro devices. This paper presents a review of FIB machining technology that include its parameter, responses, its important component systems, as well as the fundamentals of imaging, milling (etching) and deposition techniques. The application of FIB in micromachining is also presented.
Authors: Akinjide O. Oluwajobi, Xun Chen
Abstract: There is a need to choose appropriate interatomic empirical potentials for the molecular dynamics (MD) simulation of nanomachining, so as to represent chip formation and other cutting processes reliably. Popularly applied potentials namely; Lennard-Jones (LJ), Morse, Embedded Atom Method (EAM) and Tersoff were employed in the molecular dynamics simulation of nanometric machining of copper workpiece with diamond tool. The EAM potentials were used for the modelling of the copper-copper atom interactions. The pairs of EAM-Morse and EAM-LJ were used for the workpiece-tool (copper-diamond) atomic interface. The Tersoff potential was used for the carbon-carbon interactions in the diamond tool. Multi-pass simulations were carried out and it was observed that the EAM-LJ and the EAM-Morse pair potentials with the tool modelled as deformable with Tersoff potential were best suitable for the simulation. The former exhibit the lowest cutting forces and the latter has the lowest potential energy.
Authors: Mehrdad Vahdati, Ali Shokuhfar
Abstract: Ultra precision machines are used for very precise machining as well as small parts. Due to their application, the accuracy of products has been upgraded in recent years. Thus, dimensional accuracies could be compared with surface texture dimensions like roughness and etc. In order to attain dimensions with surface texture accuracy, usually micro/nano meter, it is necessary to adopt ordinary machining technologies with micro/nano techniques. This measuring by adoption leads to nano-machining. Nano-machining researches deal with all three basic components of, machine tools, work piece, and cutting tool, which have fundamental importance for development of this technique. Despite of wide range of possible researches, only part of design points of ultra precision machines have been considered in this report. Air operated systems, like air slide table, and air spindle are examples of ultra precision machine tool components. These two components have been analyzed for some of their characteristics. Experiments have been planed to extract the relationship between stiffness, employing some of the effective parameters such as air pressure and air gap. The results describe the performance condition of air table and air spindle under different loadings.
Authors: Yong Da Yan, Wei Tao Liu, Zhen Jiang Hu, Xue Sen Zhao, Jiu Chun Yan
Abstract: To study the effect of different sample materials on the nano dynamic ploughing process in the AFM tapping mode, the spring-oscillator model is employed to simulate the vibrating AFM tip to deform the sample surface. On the surface of different samples with the Young’s modulus of 0.2 GPa, 80 GPa and 180 Gpa, the interaction between the tip and the sample is simulated with different driven amplitudes, spring constants, tip radius and original tip-sample distances. These effects are studied. Results show that the sample with a smaller Young’s modulus is suitable for being used as the sample machined by the dynamic ploughing technique. When the Young’s modulus is greater than 80 GPa, the machine depth is so small that the machining process can not be controlled as we required.
Authors: Yong Da Yan, Shen Dong, T. Sun
Abstract: This study aimed to gain an in-depth understanding of the features of AFM micro probe nanomachining. With the aid of the orthogonal test analysis and synthesis method of point rating, factors of influencing the cutting process: the perpendicular load, the feed amount and the cutting speed, were analyzed. The study revealed that the feed amount and the perpendicular load had greater effect on the surface quality and machining efficiency than the cutting speed. The results were also compared with the conventional ultra-precision machining. The optimal machining parameters suitable for two application fields were achieved. This method is a novel and feasible method to perform the nanomachining.
Authors: Feng Zhou Fang, Yu Chan Liu, Qing Xiang Pei, Xiao Tang Hu
Abstract: A new method on examining the micro cracks of monocrystalline silicon during nano indentation is proposed. It is established based on a study of the increasing rate of absorbed energy in nano indentation. This method provides a simple approach in understanding whether cracks on the silicon surfaces occur, while it is tedious in conventional method.
Authors: Akinjide O. Oluwajobi, Xun Chen
Abstract: The atomic surface finish or roughness can be defined as the roughness limit of a surface. Its value has been demonstrated both in theory and in experiments to be non-zero [1, 2]. This parameter is very important in assessing the quality of high performance nanosurfaces, and so its understanding is very crucial. In this study, multi-pass nanometric atomistic simulations were carried out, with a diamond tool on a copper workpiece to create a nanosurface and the results provide the platform from which the atomic surface roughness was evaluated. The estimated surface roughness (Sa) was in the order of 0.3nm.
Authors: Akinjide O. Oluwajobi, Xun Chen
Abstract: The study of nanoscale machining phenomena and processes are effectively been carried out by using the molecular dynamics (MD) simulation. The MD provides explanation of material behaviour that are difficult to observe or even impossible through experiments. To carry out reliable simulations, the method depends on critical issues, which include the choice of appropriate interatomic potentials and the integration time step. The selection of the timestep in the MD simulation of nanomachining is the major focus of this investigation. A too low timestep would be computationally expensive and also a too high timestep would cause chaotic behaviour in the simulation. Computational experiments were conducted to check for the range of timestep that is appropriate for the simulation of nanomachining of copper. It was observed from the total energy variations, that time step in the range of 0.1 to 0.4 fs could be used to procure stable simulations in copper, for the configuation employed.
Authors: Fei Hu Zhang, Hua Li Zhang, Yong Da Yan, Jing He Wang
Abstract: Nanomachining tests have been conducted on single-crystal Al using atomic force microscope to simulate single-blade machining process of single gain. The influences of nanomachining experimental parameters (lateral feed and velocity) on the properties of engineering surface, material removal and chip formation were studied. Results indicated that the cutting depth of nanomachined surface increased as the lateral feed decreased. Insensitivity of cutting depth to velocity at same normal load was revealed. The different chip behaviors of nanomachined surface were investigated through scanning electron microscope (SEM). Results indicated that different lateral feeds caused different chip behaviors. Three typical chip behaviors were characterized as the lateral feed increased. In addition, the chip behavior and the volume of material removed were observed having no evident linear transformation with the evolution of the velocity by SEM graphics. Furthermore, it was concluded from the chip behaviors in nanomachining process that the material at high loads was removed by plastic deformation with no fracture or crack happened.
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