Progress of Precision Engineering and Nano Technology

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Authors: N. Mishima
Abstract: As has been demonstrated in the “microfactory” which is a miniature manufacturing system proposed by the author’s research group, small machine tools that are comparable in size to their target products lead to large reductions in energy consumption and area. Experiments showed that they were capable of micro mechanical fabrication. However, the design of miniature machine tools has not been fully optimized. The author proposed a design method to estimate machine tool performance. In this paper, the design tool is applied to find miniaturizing strategies. By applying the design tool, it is possible to determine which of the design parameters and error sources would significantly affect machine performance. From the results of calculation, the tool can clarify the effect of machine tool sizes imposed on the machine performances. This leads to some suggestions regarding machine tool sizes. Finally, design guidelines for miniature machine can be obtained.
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Authors: Min Qiang Pan, Yong Tang, Long Sheng Lu, Zhen Ping Wan, X.K. Liu, Xiao Qing Liu
Abstract: A passive microstructured mixer based on micro-ploughing technology with a multi-tooth tool is proposed. The mixer uses multiple three-dimensional nozzles to split one of the liquids into several micro-plumes. The fins on the surface of the nozzles induce a second liquid to generate turbulence around the local surface of the fins. The machining mechanism for fabricating 3D nozzles on a stainless steel sheet by micro-ploughing technology with a multi-tooth tool was studied. The machining process mainly involves four stages: tool-feeding, fin-forming, micro-hole-forming and tool-retracting. Simulation and flow visualization were used to evaluate its performance. The simulation results show the fin structure can induce local surface turbulence. The flow visualization indicates that when the flux is between 0.5ml/s and 3ml/s, the two liquids are fully mixed in 1second.
343
Authors: S.J. Park, S.G. Chung, Hae Do Jeong
Abstract: In this paper, a new replication technique for 1D, 2D, and 3D microstructure was introduced, in which a master pattern was made of photo-curable epoxy using microstereolithography technology, an etching process, and a dicing process. Next, it was transferred onto an epoxy. Barrier ribs were selected as the 1D microstructure, and a rectangular pattern was selected as the 2D microstructure. A helical gear was selected as one of the real 3D microstructures for this study, and these were replicated from pure epoxy. In addition, the life span of the soft mold for using the micro replication process was evaluated.
348
Authors: Y.J. Tang, Zhen Long Wang, Q. Hu, W.S. Zhao
Abstract: A miniaturized Electrical Discharge Machine (EDM) device based on ultrasonic motor has been developed to machine micro-holes in narrow space. In this mechanism, the electrode is driven without need of electrode holder, so that the mass and inertia of slider are greatly smaller, and feeding frequency of electrode can be raised compared to the conventional miniaturized EDM devices. This is a significant improvement that the electrode’s driving means varies from plane driving to line driving. Because of its advantage of compact size, the miniaturized EDM device can be fixed on robot. Differential Reciprocating Driving Method (DRDM) for EDM electrode is proposed. Feeding resolution of electrode reaches 0.5μm in stepping style, while resolution reaches 40nm in differential reciprocating style, and all above characteristics create preconditions for micro EDM machining. The holes with figures of Φ90μm inclined circle and inclined Y have been machined.
355
Authors: Zhen Long Wang, Bao Guo Zhu
Abstract: According to the present situation of microelectrode machining, the fabrication technology of microelectrode is put forward by the method of high frequency short pulses in electrochemical machining (ECM). The mechanism of pulses ECM is depicted firstly. Then the system of ECM is designed. After the experiment of technology analyzed, a microelectrode with nice surface is machined successfully. The diameter of the microelectrode is 7μm and the radius of its top is 50nm, which is made of tungsten filament. It could provide the simple electrode for further electrical machining or micro probe for scanning probe microscopy. The surface property, structure, and microhardness of the microelectrode are analyzed. The surface property and the machining capability of the microelectrode are compared with the microelectrode machined by electrical discharge machining (EDM). The superiority of the microelectrode machined by ECM is shown fully. The practicability and reliability are proved by the research of experimentations.
360
Authors: L.J. Li, Fei Hu Zhang, S. Dong
Abstract: The roughness and profiles accuracy of aspheric surface are two key factors affecting the resolution and other characteristics of optical instruments. In this paper a new grinding system-parallel grinding system was built, and an CNC system controlled by PMAC (programmable multi-axis controller) was developed, the parallel grinding system can realize Arc Envelope Grinding Method (AEGM) only through controlling 2-axis and the wear of wheel was diminished, the tool path calculation was simplified. Using this system, the roughness and profile accuracy of aspheric surface are improved.
365
Authors: Xiao Feng Zhang, Bin Lin
Abstract: The load capacity and stiffness of the aerostatic rectangular guideways, which apply annular orifice restrictor and porous restrictor respectively, were analyzed with finite difference method in this paper. A program for solving the pressure distribution, load capacity and stiffness is programmed with VB. The calculated results show that the rise of supply pressure is good for improving the load capacity and stiffness of guideways. The decrease of the orifice diameter in annular orifice restriction and the permeability in porous restriction is advantageous to improve the stiffness of guideways, but both the corresponding bearing clearance and load capacity decrease. In both the annular restriction and porous restriction, the best film thickness which make the stiffness maximum exists under the definite supply pressure and parameter of the restrictor. Under the same supply pressure, the load capacity and stiffness of porous restriction is higher than the orifice restriction. Meanwhile, the design and manufacture of porous restrictor is simple. The porous restrictor is the perfect restrictor of aerostatic guideways.
371
Authors: Xiao Quan Zhang, L. Tian
Abstract: Micro Air Vehicles (MAVs) are catching more and more attentions for their broad application in civilian and military fields. Since the theories on the aerodynamics of low Reynolds number are not maturely presented and the wind-tunnel experiments cost long periods and great expenses. The numerical simulation based on computational fluid dynamics (CFD) is a good method to choose. Through three-dimensional simulation of the wings, the aerodynamic characteristics of the flows around MAVs can be easily obtained. The tip vortices produced around low-Reynolds-number and low-aspect-ratio wings can increase the lift and stall angles. The result of numerical simulation can be used as references of theory analysis and wind-tunnel experiments.
377
Authors: Qing Liang Zhao, Ekkard Brinksmeier, Otmann Riemer, Kai Rickens
Abstract: In this paper, a novel conditioning technique features using copper bonded diamond grinding wheels of 91μm grain size assisted with ELID (electrolytic in-process dressing) as a conditioner to precisely and effectively condition nickel electroplated monolayer coarse-grained diamond grinding wheels of 151μm grain size was firstly developed. Under optimised conditioning parameters, the super abrasive diamond wheel was well conditioned in terms of a minimized run-out error and flattened diamond grain surfaces of constant peripheral envelope, with the conditioning force monitored by a force transducer as well as the modified wheel surface status in-situ monitored by a coaxial optical distance measurement system. Finally the grinding experiment on BK7 was conducted using the well conditioned wheel with the corresponding surface morphology and subsurface damage measured by AFM (atomic force microscope) and SEM (scanning electron microscope) respectively. The experimental result shows that the newly developed conditioning technique is applicable and feasible to ductile grinding optical glass featuring nano scale surface roughness, indicating a prospect of introducing super abrasive diamond wheels into ductile machining of brittle materials.
382
Authors: L. Zhou, Ying Xue Yao, Shahjada Ahmed Pahlovy
Abstract: In material nanoindentation hardness testing, the hardness will decrease with the indentation depth or peak load increase, i.e. indentation size effect (ISE). There are several models and equations were proposed to describe ISE. But the variables self-inaccurate in these models and equations, it will affect the result trueness. Single crystal silicon was used for nanoindentation experiments, and max depths were obtained from these experiments. Combining Matlab software, residual areas were obtained by atomic force microscopy (AFM). Based on max depth and residual area, a new model—residual area max depth model was proposed for indentation size effect in nanoindentaion hardness. The new model perhaps can understand and describe ISE in indentation hardness better than other models and equations.
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