共查询到20条相似文献,搜索用时 15 毫秒
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Xue-Hui Shen Jianhua Zhang Dongliang Xing Xing Yunfeng Zhao 《The International Journal of Advanced Manufacturing Technology》2012,58(5-8):553-561
The objective of this paper is to investigate the effects of assisted ultrasonic vibration on the surface roughness of machined surfaces in micro-end-milling. Series of slot-milling experiments were conducted with aluminum alloy as workpiece material. The surface roughness of slot bottom surface and vertical side wall surface of slot was studied, respectively. It is found that surface roughness of the machined slot bottom surface could increase to varying degrees because of ultrasonic vibration in most of the studied cases, and this deterioration becomes more apparent when large feed per tooth and low-spindle speed were adopted. As for the vertical side wall surface of the slot, there is an obvious improvement of surface roughness when ultrasonic vibration is applied. Based on analysis of variance analysis, further study indicates that the surface roughness of vertical side wall surface of the slot is determined by several key parameters including spindle speed, feed per tooth and amplitude in ultrasonic vibration-assisted milling. An optimal combination of these parameters is of great benefit to achieving small surface roughness. 相似文献
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Y. Peng Z. Liang Y. Wu Y. Guo C. Wang 《The International Journal of Advanced Manufacturing Technology》2012,62(5-8):563-568
Elliptic ultrasonic vibration-assisted grinding has been proven to be a high-efficiency machining technique for some brittle materials. This paper aims to investigate the chip generating characteristics in grinding of brittle materials with vertical elliptic vibration assistance. Vertical elliptic ultrasonic vibration-assisted grinding for precision machining brittle polysilicon is suggested and tested. The mechanism of chip generation and characteristics of surfaces in ductile mode, machined by ultrasonic vibration-assisted grinding, are investigated. As a result, when microgrinding by ultrasonic vibration, it was confirmed that the continuous chips generated by ductile mode can be more easily be fully developed. 相似文献
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An experimental study of ultrasonic vibration-assisted grinding of polysilicon using two-dimensional vertical workpiece vibration 总被引:2,自引:2,他引:0
Y. Peng Y. B. Wu Z. Q. Liang Y. B. Guo X. Lin 《The International Journal of Advanced Manufacturing Technology》2011,54(9-12):941-947
An experimental study of polysilicon grinding with ultrasonic vibration assistance was presented. The two-dimensional (2D) vertical vibration was applied on the workpiece directly and vibrated perpendicular to both the workpiece and grinding wheel. The grinding forces were measured using a three-component dynamometer, and the surface conditions were examined using a surface profilometer and a laser microscope. The experimental results showed that the grinding force and surface roughness with ultrasonication were much less than those in conventional grinding. In the case of ultrasonication, the wheel speed and worktable feed rate would have a more positive effect on the grinding force decrement/increment, especially for the tangential force while the wheel depth of cut had a negative effect. The surface condition of the ground polysilicon surface was improved with the assistance of ultrasonication. This research indicated that the 2D ultrasonic vibration-assisted grinding technique can be an effective method for the high-efficiency machining of hard brittle polysilicon material. 相似文献
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J. C. Miao G. L. Chen X. M. Lai H. T. Li C. F. Li 《The International Journal of Advanced Manufacturing Technology》2007,31(9-10):897-904
In recent years, the miniaturization of products has become a trend all over the world. Besides conventional precision manufacturing technology and micro-electro-mechanical systems (MEMS), micro/meso mechanical manufacturing (M4) technology is regarded as another choice for an effective method to fabricate micro complicated 3D features, which need special attention paid to. In micro-end-milling machining, the stiffness of a micro-end-milling machine tool is somewhat lower, due to the size effect of material, and also, obviously, the ploughing condition and the quite slender end-milling tool. Thus, the stability of a micro-end-milling machine is very weak. This paper reviews the state-of-the-art of studying chip formation and dynamic problems in micro-end-milling, and discusses the possible future works in this field. 相似文献
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Jeong Ho Lee Soo Young Kang Tong Seop Kim 《Journal of Mechanical Science and Technology》2012,26(11):3733-3740
This paper presents models for simulating the operation of a polymer electrolyte membrane fuel cell (PEMFC) system and the results of the dynamic simulations. The entire system included a PEMFC stack and balance-of-plant components such as an air supply blower, a membrane humidifier, a fuel supply unit, and a heat management unit. Mathematical modeling for the computation of power generation and heat transfer of the PEMFC stack, the heat and mass transfer of the humidifier, and the energy transfer of the cooling system was set up. Theoretical and experiential data such as the voltage-current density relationship of the cell stack and the performance maps of blowers and pumps, together with semi-theoretical heat and mass transfer equations, were used to represent the characteristics of all the components. The effect of the thermal inertia of solid parts was considered in the fuel cell stack, the membrane humidifier, and the radiator. System dynamic behaviors under various operating conditions due to changes in stack current and ambient temperature were predicted. The sudden abnormal operations of the cooling water circulation pump and the radiator fan were also simulated as an example of component malfunctions. 相似文献
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Priyabrata Sahoo 《Machining Science and Technology》2019,23(3):407-430
This work proposed an improved mechanistic model for prediction of cutting forces in micro-milling process. The combined influences of tool run out, trochoidal trajectory of the tool center, overlapping of tooth, edge radius and minimum chip thickness are incorporated in this model to realize the exact cutting phenomenon. Moreover, an improved undeformed chip thickness algorithm has been presented by considering tool run out, minimum chip thickness and trajectory of all passing teeth for one complete revolution of the tool instead of only the current tooth trajectory. For estimation of tool run out, a model based on the geometry of the two fluted end mill cutter has been developed. Effects of trochoidal trajectory of the tool center and tool run out are found to be significant as each tooth has a different chip load. Further, the effect of minimum chip thickness is found to be significant at lower feed value. The proposed model has been validated by micro-milling experiments on Ti6Al4V-titanium alloys using uncoated flat end mill cutter. The predicted cutting forces were found to be in good agreement with the experimental cutting forces in both feed and cross feed directions. 相似文献
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Studies on friction and wear properties of surface produced by ultrasonic vibration-assisted milling
Xuehui Shen Jianhua Zhang 《The International Journal of Advanced Manufacturing Technology》2013,64(1-4):349-356
The grinding of elliptical gears on a computer numerical control (CNC) gear grinder with conical wheel is studied according to the mesh theory of elliptical gears. Two machining methods form the machine structure and movement, namely a mobile grinding wheel type and a fixed grinding wheel type. Mathematical models of the movement relation for the elliptical gear grinding process are built up. Since the teeth of the elliptical gears are different from each other, their generating length is also different. Based on the analysis of generating and indexing movement, a universal generating length formula of each tooth is proposed. Basic machining parameters of each tooth, for these two types of machines, are computed using a practical example. The dynamic simulation of generating track is given. The research results show that the grinding of elliptical gears with a CNC conical wheel gear grinder is feasible. 相似文献
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Y. Peng Z. Liang Y. Wu Y. Guo C. Wang 《The International Journal of Advanced Manufacturing Technology》2012,59(1-4):67-72
The purpose of this paper is to investigate the effects of vibration on the surface and tool wear in scratching of brittle materials. In the past, research methodology of vibration cutting has mainly involved vibrating tool parallel to cutting direction. In this paper, a new approach is proposed by an elliptic ultrasonic vibrating workpiece. It presents the fundamental principles and mechanism of ultrasonic machining together with experimental results of scratching of polysilicon with parallel and vertical ultrasonic vibration assistance. With the elliptic ultrasonic vibration assistance, the brittle material would be more likely to be ductilely removed than in conventional condition, and tool wear could be decreased in scratching of brittle materials. 相似文献
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The drilling operation occupies an important position in the aircraft assembly workload, and it accounts for a large proportion of the assembly cost. Previous reports show that drilling quality affects aircraft safety factor such as the probability of fatigue failure accidents. This paper proposes an automatic machining system for curved surface drilling. In this scheme, the self-adaption normal direction is realized by using the secondary positioning strategy (primary positioning and precise positioning). An elastic structure and the key positions smooth processing are applied to enhance the positioning guidance. The active variable stiffness mechanism satisfies the different requirements for system stiffness during the positioning stage and the drilling stage. Expansion sleeve locking and state switching of drilling assistance pneumatic cylinder lead to changes in the actuator's DOF and external forces, thereby achieving active control of the stiffness. Vibration-assisted machining technology is introduced to improve drilling quality. Compared with conventional drilling, the results show that this drilling system produces thin and slender chips, smaller burrs, and better internal surface quality. 相似文献
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Xu Yingshuai Gao Fei Zou Ping Zhang Qinjian Fan Fanglei 《Journal of Mechanical Science and Technology》2020,34(9):3791-3806
Journal of Mechanical Science and Technology - When processing difficult-to-cut materials, conventional turning (CT) typically suffers from the problems of large cutting force, difficult chip... 相似文献
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Xue-Hui Shen Jian-Hua Zhang Hua Li Jin-Jun Wang Xiao-Chen Wang 《The International Journal of Advanced Manufacturing Technology》2012,63(1-4):41-49
The objective of this paper is to investigate the effects of assisted ultrasonic vibration in the operation of micro end milling. Based upon numerical analysis for the trajectory of a tool tip of a two-flute end mill, it was found that the assisted feed direction ultrasonic vibration can achieve separate-type milling that is different from conventional operation by reasonable parameter matching. To validate theoretical analysis and investigate the influence of ultrasonic vibration on milling process, a slot-milling experiment was conducted on an aluminum alloy work piece. The desired ultrasonic vibration was applied in the feed direction by an ultrasonic vibrator. Through investigating and comparing some experimental results involving cutting force, chip formation, surface topography, surface roughness, and machining dimensional accuracy, the authors found that micro end milling with ultrasonic vibration in the feed direction leads to a pulse-like cutting force and produces uniform small chips. Assisted ultrasonic vibration in the feed direction has a negative effect on the surface roughness of the slot bottom, but a positive effect on the dimensional accuracy of the slot width. 相似文献
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José Antonio Pérez José Antonio Orosa 《The International Journal of Advanced Manufacturing Technology》2010,46(5-8):605-610
This paper introduces a new multilayer perceptron neural model for laser surface heat treatments based on Green's function. Due to its high versatility, efficiency, and low simulation time, this model is suitable not only for the analysis and design of control systems but also for the development of an expert real time supervision system, allowing the detection and prevention of any failure during the treatment. 相似文献