共查询到20条相似文献,搜索用时 15 毫秒
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Recent trend in societies is to have micro products in limited space. Efficient micromachining technologies are essential to fabricate micro products which in turn will be helpful in saving material, energy and enhancing functionality. For micromachining, micro tool is very much essential. This paper is aimed at finding the most suitable and quickest method of micro tool fabrication by electrochemical machining. Tungsten micro tools were fabricated at different machining conditions to know the influences of voltage, frequency of tool vibration, amplitude of vibration of tungsten tool, concentrations of electrolyte and dipping length of tool inside the electrolyte. Fabrication of uniform diameter of micro tool is possible at each applied voltage starting at 2 V to higher volt utilizing vibration with appropriate amplitude. Good quality micro tools with different shapes can be fabricated by controlling a proper diffusion layer thickness within a very short time introducing the vibrations of micro tool. Finally, the fabricated micro tools were applied for machining precise micro holes and micro channel using electrochemical micromachining (EMM). 相似文献
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Accurate and precise micro tools are essential for the micromachining of complex micro features in a wide range of engineering materials including metals and ceramics. Existing micro tool fabrication processes suffer from drawbacks such as surface cracks, residual stress and deformations. Electrochemical machining of micro tools is proposed in this work to overcome these limitations. In this research, a mathematical model has been developed to predict the diameter of the micro tool fabricated. Experimental verification of the model using an in-house built micro electrochemical machining system reveals good correlation with theoretical predictions. Using the procedure described in this paper, very high aspect ratio (280–450) tungsten micro tools have been produced. 相似文献
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Experimental investigation on the influence of electrochemical machining parameters on machining rate and accuracy in micromachining domain 总被引:3,自引:0,他引:3
B. Bhattacharyya J. Munda 《International Journal of Machine Tools and Manufacture》2003,43(13):1301-1310
Non-conventional machining is increasing in importance due to some of the specific advantages which can be exploited during micromachining operation. Electrochemical micromachining (EMM) appears to be a promising technique, since in many areas of application, it offers several special advantages that include higher machining rate, better precision and control, and a wider range of materials that can be machined. A better understanding of high rate anodic dissolution is urgently required for EMM to become a widely employed manufacturing process in the micro-manufacturing domain. An attempt has been made to develop an EMM experimental set-up for carrying out in depth research for achieving a satisfactory control of the EMM process parameters to meet the micromachining requirements. Keeping in view these requirements, sets of experiments have been carried out to investigate the influence of some of the predominant electrochemical process parameters such as machining voltage, electrolyte concentration, pulse on time and frequency of pulsed power supply on the material removal rate (MRR) and accuracy to fulfil the effective utilization of electrochemical machining system for micromachining. A machining voltage range of 6 to 10 V gives an appreciable amount of MRR at moderate accuracy. According to the present investigation, the most effective zone of pulse on time and electrolyte concentration can be considered as 10–15 ms and 15–20 g/l, respectively, which gives an appreciable amount of MRR as well as lesser overcut. From the SEM micrographs of the machined jobs, it may be observed that a lower value of electrolyte concentration with higher machining voltage and moderate value of pulse on time will produce a more accurate shape with less overcut at moderate MRR. Micro-sparks occurring during micromachining operation causes uncontrolled material removal which results in improper shape and low accuracy. The present experimental investigation and analysis fulfils various requirements of micromachining and the effective utilization of ECM in the micromachining domain will be further strengthened. 相似文献
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V. K. Jain P. M. Dixit P. M. Pandey 《International Journal of Machine Tools and Manufacture》1999,39(1):3655
The electrochemical spark machining (ECSM) process has been proved as a potential process for machining of low machinability high-strength electrically non-conducting materials, but the mechanism of material removal during the process, by and large, is not yet understood. In the present work, the electrochemical discharge is modelled as a phenomenon similar to that which occurs in arc discharge valves. This phenomenon is used to explain various experimental results, on the basis of circuit and arc discharge valve characteristics. The spark energy and the approximate order of hydrogen gas bubble diameter are computed by the proposed valve theory. Material removal rate is evaluated by modelling the problem as a 3-D unsteady state heat conduction problem. The problem is solved by the finite element method to compute the temperature distribution which is post-processed for estimating material removal per spark, overcut obtained in the machined cavity, and attainable maximum penetration depth. The conclusion drawn is that the application of valve theory to the ECSM process seems to be realistic. Estimated material removal rate, overcut and maximum penetration depth show a good agreement with experimental findings. 相似文献
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《Journal of Materials Processing Technology》2014,214(4):892-898
Electrochemical discharge machining (ECDM), also known as spark assisted chemical engraving (SACE), is an effective micro-machining process for non-conducting materials. Process modeling of ECDM, including spark generation and material removal, is not fully established however. Empirical estimation for discharge energy results in large prediction error of material removal and is hard to experimentally validate. In this paper, an experiment-based stochastic model for spark energy estimation is presented. Tapered tool electrodes were fabricated by electrochemical machining (ECM) to improve the consistency of spark generation. Energy of sparks was experimentally determined and fit into a two-component mixture log-normal distribution to reveal electrochemical characteristics of tool electrodes. A finite element based model was established to correlate spark energy and the geometry of removed material. Material removal was treated as heat transfer problem because electrical energy released by spark generation transfers into thermal energy on the workpiece, resulting in material removal due to thermal melting and chemical etching. Predictions of material removal by the model demonstrated good consistency with experimental results. 相似文献
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《International Journal of Machine Tool Design and Research》1986,26(3):323-338
The authors aim to improve the reliability and speed of workpiece shape prediction for electrochemical machining. A review of some previous mathematical modelling work is followed by a resume of the Boundary Element Method. Linear and quadratic elements are used herein to represent the boundaries and, because the workpiece shape changes as machining progresses, an automatic re-noding procedure is adopted after each iteration. The effect of element and time step size on the accuracy of the workpiece profile is studied, accuracy being measured by comparing converged parts of the workpiece shape with exact equilibrium solutions. The paper reveals considerable promise for boundary element simulation particularly when it is reasonable to assume that homogeneous physical conditions exist in the inter-electrode zone. 相似文献
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H. Hocheng Y.H. Sun S.C. Lin P.S. Kao 《Journal of Materials Processing Technology》2003,140(1-3):264-268
Electrochemical machining (ECM) has been increasingly recognized for the potential for machining, while the precision of the machined profile is a concern of its application. A process to erode a hole of hundreds of micrometers on the metal surface is analyzed in the current paper. A theoretical and computational model is presented to illustrate how the machined profile evolves as the time elapses. The analysis is based on the fundamental law of electrolysis and the integral of a finite-width tool. The paper also discusses the influence of experimental variables including time of electrolysis, voltage, molar concentration of electrolyte and electrode gap upon the amount of material removal and diameter of machined hole. The results of experiment show the material removal increases with increasing electrical voltage, molar concentration of electrolyte, time of electrolysis and reduced initial gap. The time of electrolysis is the most influential factor on the produced diameter of hole. 相似文献
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This paper describes the development and application of the boundary element method to model the machining of simple milling and turning features. The 3D model uses linear triangular elements to discretise the workpiece and tool surfaces. Highlights of the program include the use of analytical integration to calculate the element matrices rather than numerical, and the automatic refinement of the mesh as the workpiece is progressively machined. The program has been tested for milling slots using a rectangular tool and for turning a thin-walled tube. It is shown that there is good agreement between the predicted and experimental results. 相似文献
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《CIRP Annals》2020,69(1):229-232
Sapphire capillaries manufactured with high efficiency and precision are needed for use in laser–plasma accelerators. A hybrid manufacturing process combining femtosecond laser machining and diamond tool micromilling was applied. By using a femtosecond laser mounted on a 5-axis machine, a capillary with a groove width of 630 µm and length of 90 mm was fabricated on a sapphire plate within 5 h. The surface roughness of the bottom of the cylinder groove was finished to 7.1 nm in Sa by milling with a polycrystalline diamond end mill. 相似文献
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Improving machining performance of wire electrochemical discharge machining by adding SiC abrasive to electrolyte 总被引:2,自引:0,他引:2
C.T. Yang S.L. Song B.H. Yan F.Y. Huang 《International Journal of Machine Tools and Manufacture》2006,46(15):2044-2050
The use of wire electrochemical discharge machining (WECDM) to slice hard brittle materials has recently been studied because its effectiveness is independent of the mechanical characteristics of the machined materials. Therefore, materials with high hardness, brittleness, strength and electrical insulation, which are difficult-to-cut, can be machined. In ECDM, the electrochemical reaction produces hydrogen bubbles, which accumulate around the cathode. A thin gas layer forms on the surface of the electrode and isolates the electrode from the electrolyte. When a voltage that exceeds the critical voltage is applied, continuous discharge occurs. The material near the electrode is removed by the discharge erosion and chemical etching. The use of WECDM to cut electrically insulating materials has only recently been investigated. However, the breakdown of the gas in the bubbles and the vibration of the wire in WECDM strongly affect the shape accuracy. This work aims to improve the over cut quality by adding SiC abrasive to the electrolyte. A mechanism that combines discharge, chemical etching and abrasive cutting is studied. The effects on expansion, roughness and material removal rate (MRR) are discussed. The experimental results reveal that adding abrasive reduces the slit expansion because it increases the critical voltage. The particles disrupt the bubble accumulation to form an isolating layer around the wire, increasing the critical voltage and reducing the discharge energy. The surface roughness is improved because the abrasive helps to refine the micro-cracks and melted zone that is formed by discharge heat erosion. Meanwhile, smaller grit produces lower roughness. The quality of the slit can be controlled; its expansion and roughness of the slit are 0.024 mm and 0.84 um Ra, respectively. 相似文献
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不锈钢表面的电化学机械复合抛光 总被引:1,自引:0,他引:1
胡苏 《组合机床与自动化加工技术》2003,(7):64-65,67
介绍了一台由立式铣床改装的电化学机械复合抛光装置。讨论了加工电压、磨轮压力与加工效率的关系以及加工电压对表面粗糙度的影响。 相似文献
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Shi Hyoung Ryu 《Journal of Materials Processing Technology》2009,209(6):2831-2837
This paper describes micro electrochemical machining of stainless steel in an environmentally friendly electrolyte of citric acid. Electrochemical dissolution region is minimized by applying a few hundred nanosecond duration pulses between the tungsten SPM tip and the work material. Electrochemical machining (ECM) characteristics according to citric acid concentration, feed speed and electric conditions such as pulse amplitude, pulse frequency, and tool electrode baseline potential are investigated through a series of experiments. Micro holes of 60 μm in diameter with the depth of 50 μm and 90 μm in diameter with the depth of 100 μm are perforated using citric acid electrolyte. Square and circular micro cavities are also fabricated by electrochemical milling. This research may contribute to the development of safe and eco-friendly micro manufacturing technology. 相似文献
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This paper presents a hybrid process of grinding and electrochemical removal for machining of precision small holes with hard-to-machine materials. In the process, a metal rod with coated abrasives as cathode tool rotates at high speed and removes material electrochemically and mechanically for a pre-machined pilot hole. The effects of process parameters on the hole surface quality and dimensional accuracy were demonstrated experimentally. Material removals on grinding and electrochemical machining are well balanced by rationally determining machining voltage, tool rotation speed and feed rate. Precision holes of diameters down to 0.6 mm with sharp edges and without burrs have been produced. 相似文献
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Current efficiency determinations from weight-loss measurements were made on pure iron and pure nickel anodes in 4M NaClO3 solution in a flow cell at flow rates between 500 and 3000 cm/s in a current range from 5 to 50 A/cm2. The current efficiency for metal removal was virtually independent of current density and flow rate on iron anodes. On nickel anodes the current efficiency increased strongly with current density. In the high current density region, the current efficiency decreases with flow rate up to 2000 cm/s and then increases with higher flow rates. This behavior was accounted for by differences in the nature and properties of the anodic films formed on iron and nickel anodes. 相似文献