Papers by Keyword: Micro WEDM

Abstract: This paper presents modeling and analysis of machining characteristics of Micro Wire Electro Discharge Machining (Micro-WEDM) process on Aluminium alloy (AL 2024 T351) using the Response Surface Methodology (RSM) and Artificial Neural Network (ANN). The input variables of Micro-WEDM process were voltage, capacitance and feed rate. The surface roughness is considered as a response variable. Experiments were carried out on Aluminium alloy using Central Composite Design (CCD). The RSM and ANN models have been developed based on experimental designs for surface roughness. Analysis of variance (ANOVA) has been employed to test the significance of RSM model. It has been found out that all the three process parameters are significant and their interaction effects are also significant on the surface roughness. Finally predicted values were compared with both modeling methodologies RSM and ANN.

Abstract: Micro Electrical discharge machining (µEDM) is an electro thermal process, the cutting force is negligibly small and material removal occurs irrespective of hardness of work piece material .Micro electrical discharge machining process is capable of machining of complex shape, which is difficult to machine in conventional machining process. Last decade, the EDM process involved demand for machining requirements with short period. Since the major risk of wire breakage, deflections of electrodes were affecting the performance accuracy of EDM operation. This paper describe about a comprehensive review of micro electro discharge machining process and its process optimization techniques used for last 10 years. Micro electro discharge machining has more important given to difficult to machine materials. In order to improve the surface integrity and performance of process, need to select proper process parameters. It reports on the Micro EDM research involving the optimization of the process parameters surveying the influence of the various factors affecting the machining performance and productivity.

Abstract: This paper presents the estimation of kerf width in micro wire electrical discharge machining (micro WEDM) in terms of machining parameters of capacitance and gap voltage. An empirical model is developed by the analysis of variance (ANOVA) of experimental data. Using a wire electrode of 70 µm diameter, a minimum kerf width is found to be 92 µm for the micro WEDM parameters of 0.01 µF capacitance and 90.25 V gap voltage. Around 30% increament of the kerf is found to be high. The analysis also revealed that the capacitance is more influential parameter than gap voltage on kerf width produced by micro WEDM. As the gap voltage determines the breakdown distance and affects the wire vibration, the wire vibration factor is to be considered in the analysis and in formulation of model in future study.

Abstract: This paper discusses a processing preparation for micro-electrode array fabrication by micro wire electrical discharge machining. Based on a self-developed micro-WEDM machine tool and adopted thin tungsten wire electrode of 30μm in diameter, a series of experiments on micro-electrode array machining are introduced. The relationship between the discharge gap and working area of wire discharge under given voltage is investigated. The examination for micro-girder structure forming process has gone along and the axle journal's minimized width of least micro girder which could not bring on machining flexural thermal deformation has been obtained. The clamping method of work-piece intended for electrode array fabrication is analyzed and a special fixture is designed. The factors affecting forming accuracy are summarized. An amounted 5×5 squared-disk-type micro-electrode array structure with a high aspect ration, namely 20μm in axle journal width and 500μm in length of a single electrode, has been machined successfully.

Abstract: A Micro WEDM (Micro Wire Electrical Discharge Machining) CNC system is presented in this paper. Its hardware platform adopted PC with movement control card. For Micro WEDM system is a typical multitasking and real-time system, the CNC software adopted multithread and module structure to perform the parallel tasks and real-time tasks. It also adopted fuzzy control algorithm to control the feeding speed and acceleration. Practical proved that the CNC system is not only low cost and easy to development, but also satisfied the need of Micro WEDM.

Abstract: The surface micro-topography of micro-WEDM is random, disordered and multi-scale and has been proved that it is fractal with the characteristic of self-affinity within a certain scale on the basic of the fractal geometry theory. According to the characterization of W-M fractal function, the principles of three evaluation methods about power spectrum method, structure function method and wavelet criterion have been described. The advantages and disadvantages of them evaluating the fractal property of the surface micro-topography of micro-WEDM have been compared in this paper. The experimental results indicate that the wavelet criterion is more stable and dependable than the other two methods, so the fractal dimension D of the surface micro-topography of micro-WEDM has been calculated using it. The result shows that the fractal dimension has the tendency of decrease with the increase of root mean square deviation (Sq) value while it is not absolutely monotonic, which can be used as a beneficial supplement to traditional evaluation parameters of surface roughness.

Abstract: The surface micro-topography characteristics of micro-WEDM, which can have a directly significant impact on the parts usability properties, have been attached more and more importance by people. In this study, the method of statistical analysis is applied to work out the two-dimensional autocorrelation function figure and the power spectrum density function figure of the surface micro-topography of micro-WEDM. It can be seen that there are more sharp and narrow peaks and high frequency components, meanwhile, there are some low frequency wave components on the surface. A conclusion is arrived at that the three-dimensional (3D) surface micro-topography of micro-WEDM shows isotropy through analyzing its texture characteristics. The results can provide the theoretical basis for further establishing the appropriate evaluation parameters for the surface roughness of micro-WEDM.

Abstract: In Micro Wire Electrical Discharge Machining (Micro-WEDM), the kerf width varies with different machining parameters, which will greatly influence the machining precision. In order to study the kerf variations in Micro-WEDM, the influence of kerf variation is analyzed and the experiment considering the kerf width and machining speed are performed on self-developed micro-WEDM under different machining parameters. With the reference of the experiment results, 32μm wide slot is machined with Φ30μm wire-tool on stainless steel workpiece.

Abstract: Micro WEDM is a versatile technique used to machine electrically conductive materials to make components for micro system technologies. This paper presents an attempt to develop an appropriate machining strategy for micro WEDM of titanium alloy using zinc coated copper wire of 70 µm diameter. Voltage, capacitance, feed, wire tension and wire speed were taken as input parameters. Surface finish is considered as the measure of process performance. Design of experiments was done using Taguchi L16 orthogonal array and optimization was carried out using Taguchi S/N ratio technique. The results obtained from the experiments were analyzed with ANOVA method to find the significance of each input factor on the surface quality. In addition ANN model was developed and trained.

Abstract: This paper aims to investigate the performance of narrow beam machined by MWEDM. The narrow beam machining experiments are carried out on self-development Micro-WEDM with Φ30μm electrode wire. Narrow beams with the width around 10μm are machined on E52100 steel under different machine conditions (discharge energy, servo reference voltage). Based on the analysis of the experiments results, the coupled temperature and stress analysis using ANSYS finite element analysis software is performed to investigate causes of the failures on process.