Browsing by Subject "Electrical discharge machining"

Now showing 1 - 5 of 5

Open Access
Experimental and finite element analysis of EDM process and investigation of material removal rate by response surface methodology
(2013) Hosseini Kalajahi, M.; Rash Ahmadi, S.; Nadimi Bavil Oliaei, S.
In this study, thermal modeling and finite element simulation of electrical discharge machining (EDM) has been done, taking into account several important aspects such as temperature-dependent material properties, shape and size of the heated zone (Gaussian heat distribution), energy distribution factor, plasma flushing efficiency, and phase change to predict thermal behavior and material removal mechanism in EDM process. Temperature distribution on the cathode has been calculated using ANSYS finite element code, and the effect of EDM parameters on heat distribution along the radius and depth of the workpiece has been obtained. Temperature profiles have been used to calculate theoretical material removal rate (MRR) from the cathode. Theoretically calculated MRRs are compared with the experimental results, making it possible to precisely determine the portion of energy that enters the cathode for AISI H13 tool steel. Also in this paper, the effect of EDM parameters on MRR has been investigated by using the technique of design of experiments and response surface methodology. Finally, a quadratic polynomial regression model has been proposed for MRR, and the accuracy of this model has been checked by means of analysis of residuals. © 2013 Springer-Verlag London.
Open Access
Fabrication of PCD mechanical planarization tools by using μ-wire electrical discharge machining
(Elsevier, 2016) Oliaei, Samad Nadimi Bavil; Karpat, Yiğit
Fabrication of micro components made from difficult-to-cut materials require the use of micro cutting tools which can withstand the harsh conditions during machining. Polycrystalline diamond micro tools, produced using micro wire electro discharge machining, have been used to machine silicon. In this study, fabrication of PCD planarization tools having micro-pyramid lattice structure is considered. A tungsten wire with 30 μm diameter was used, which makes it possible to obtain very precise micro-features by employing extremely low discharge energies. The performance of the tools is investigated through micro scale grinding of silicon and appropriate machining parameters which resulted in ductile regime machining of silicon are determined.
Open Access
Mathematical and numerical modeling of the effect of input-parameters on the flushing efficiency of plasma channel in EDM process
(Elsevier Ltd, 2013) Shabgard, M.; Ahmadi, R.; Seyedzavvar, M.; Oliaei, S.N.B.
In the present study, the temperature distribution on the surface of workpiece and tool during a single discharge in the electrical discharge machining process has been simulated using ABAQUS code finite element software. The temperature dependency of material properties and the expanding of plasma channel radius with time have been employed in the simulation stage. The profile of temperature distribution has been utilized to calculate the dimensions of discharge crater. Based on the results of FEM and the experimental observations, a numerical analysis has been developed assessing the contribution of input-parameters on the efficiency of plasma channel in removing the molten material from molten puddles on the surfaces of workpiece and tool at the end of each discharge. The results show that the increase in the pulse current and pulse on-time have converse effects on the plasma flushing efficiency, as it increases by the prior one and decreases by the latter one. Later, the introduced formulas for plasma flushing efficiency based on regression model were utilized to predict the cardinal parameter of recast layer thickness on the electrodes which demands expensive empirical tests to be obtained. © 2012 Elsevier Ltd. All rights reserved.
Open Access
Micro electro discharge machining of tungsten carbide and polycrystalline diamond : an experimental analysis of process parameters
(2013) Özdemir, Cem
Electro discharge machining (EDM) is a manufacturing process where material removal is realized through electrical discharges between two conductive materials without applying any external forces. As a result, high aspect ratio micro features on difficult-to-cut materials such as tungsten carbide and polycrystalline diamond can be obtained. In this study, influences of micro-EDM process parameters such as voltage, capacitance, and rotational speed on material removal rate and surface quality have been investigated using experimental techniques. Experimental results have revealed that capacitance and voltage applied during EDM process have significant effects on material removal rate and surface roughness. Regression models have been calculated to represent the relationships between process inputs and outputs which can be used to calculate processing time and to predict surface finish. In addition, a process planning software for wire-EDM process, which is capable of generating necessary tool paths during fabrication of micro tools, has been developed. The software is also capable of producing the solid model of the micro tools which can be utilized in computer aided engineering applications.
Open Access
On-machine fabrication of PCD and WC micro end mills using micro electro discharge machining
(Inderscience Enterprises Ltd., 2014) Oliaei, S.N.B.; Özdemir, C.; Karpat, Y.
Micro electro discharge machining (μ -EDM) process can be used to fabricate micro-milling tools of different geometries from tungsten carbide (WC) and polycrystalline diamond (PCD). The non-contact nature of EDM process makes micro tool fabrication a challenging task while offering the advantage of eliminating tool run out and clamping errors since micro tools fabricated on-machine. The tools are fabricated and used on the same spindle. In this study, a combination of block-EDM and wire electro discharge grinding (WEDG) techniques are used to fabricate micro end mills of different geometries. The influences of EDM process parameters on material erosion rate and surface roughness are examined. The performance of the fabricated micro-tools in ductile mode machining of fused silica has been investigated. It is found that micro end mills can be used to fabricate prototypes of microfluidics chips with acceptable quality. © 2014 Inderscience Enterprises Ltd.