Pulses machining

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  • This book discusses aspects of laser pulses generation, characterization, and practical applications. Some new achievements in theory, experiments, and design are demonstrated. The introductive chapter shortly overviews the physical principles of pulsed lasers operation with pulse durations from seconds to yoctoseconds. A theory of mode-locking, based on the optical noise concept, is discussed. With this approximation, all paradoxes of ultrashort laser pulse formation have been explained.

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  • (BQ) The present work deals with the comparison of the MRR for EN19 and EN41 material in a die sinking EDM machine. The various input factors like Pulse ON time, Pulse OFF time, Discharge current and voltage were considered as the input processing parameters, while the MRR is considered as the output. Optimization using Taguchi method was performed to predict the best combination of inputs towards maximum output.

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  • (BQ) The article presents an idea about the effect of the various input process parameters like Pulse ON time, Pulse OFF time, Discharge Current and Voltage over the Surface Roughness for an EN41 material. Here, 5 different output parameters concerned with surface roughness like Ra, Rq, Rsk, Rku and Rsm are taken and optimized accordingly, using the Grey-Taguchi method.

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  • (BQ) In this research work two different materials have been used as work pieces. These EN8 and D3 steel materials have been machined in an Electrical discharge machine which has wide application in Industry fields. The important process parameters that have been selected are peak current, pulse on time, die electric pressure and tool diameter. The outputs responses are material removal rate (MRR), tool wear rate (TWR) and surface roughness (SR).

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  • (BQ) In this paper, working current, working voltage, oil pressure, spark gap Pulse On Time and Pulse Off Time on Material Removal Rate (MRR) and Surface Finish (Ra) has been studied. Empirical models for MRR and Ra have been developed by conducting a designed experiment based on the Grey Relational Analysis. Genetic Algorithm (GA) based multi-objective optimization for maximization of MRR and minimization of Ra has been done by using the developed empirical models. Optimization results have been used for identifying the machining conditions.

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  • (BQ) This paper is devoted to a study of the influences of EDM parameters on surface roughness for machining of 40CrMnNiMo864 tool steel (AISI P20) which is widely used in the production of plastic mold and die. The selected EDM parameters were pulsed current (8, 16 and 24 A), pulse time (2, 3, 4, 6, 12, 24, 48 and 100 s) and pulse pause time (2 and 3s). It was observed that surface roughness of workpiece and electrode were influenced by pulsed current and pulse time, higher values of these parameters increased surface roughness.

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  • (BQ) In this research, an iso duration current pulse generator has been proposed to achieve good surface finish. An experimental performance evaluation has been conducted with conventional transistor pulse train generator and modified iso current pulse generator by Taguchi L27 orthogonal array design. The machining characteristics have been evaluated for both the pulse generators. It is found the that modified iso duration current pulse generator has produced better surface quality with higher material removal rate than the conventional transistor pulse train generator.

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  • Whereas spark erosion and lasermachining are suitable for any metal, the use of mechanical precision machining and the tools suitable for this type depend on the stability of the alloy. For brass and copper, natural diamondmicrotools are suitable and widely used, while for stainless steel and nickel- based alloys, hardmetal tools are needed. Figure 1.3 shows a natural diamond cutter, whereas Figure 1.4 shows a hard metal drill. Figure 1.5 shows photos of a rhodium honeycombmicrochannel catalyst system.

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  • (BQ) Part 1 book "High performance control of AC drives with matlab simulink models" has contents: Introduction to high performance drives, mathematical and simulation models of AC machines, mathematical and simulation models of AC machines, pulse width modulation of power electronic DC-AC converter

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  • (BQ) The adequate selection of manufacturing conditions is one of the most important aspects to take into consideration in the die-sinking electrical discharge machining (EDM) of conductive ceramics, as these conditions are the ones that are to determine such important characteristics as: surface roughness, electrode wear (EW) and material removal rate, among others. In this work, a study was carried out on the influence of the factors of intensity (I), pulse time (ti) and duty cycle (η) over the listed technological characteristics.

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  • (BQ) The present study discusses about having an overview of the EDM process, modeling of process parameters, and influence of process parameters such as input electrical variables, pulse shape, and discharge energy on performance measures such as material removal rate, surface roughness and electrode wear rate.

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  • (BQ) Surface integrity and dimensional accuracy remain critical concern in Electrical Discharge Machining (EDM). The current research work aims at investigating the influence of various EDM process parameters like pulse current (Ip), pulse-on time (Ton), tool work time (Tw) and tool lift time (Tup) on various aspects of surface integrity like white layer thickness (WLT), surface crack density (SCD) and surface roughness (SR). The dimensional accuracy, characterized by over cut (OC), has also been studied in the similar way.

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  • (BQ) In this paper, an easily implemented method is developed to describe the variations of EDM process, represented by gap states. On the basis of a time series of gap states from a machining process, the paper first studied a general descriptive model for EDM process, and then equivalently simplified the model for application; after spectral analysis, preprocessing of data, parameters selection and model validation proposed a well-defined model. Finally, by using this model structure and size, an online time-varied predictive model was developed.

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  • (BQ) This paper investigated the effects of machining parameters on surface roughness of wire EDMed DC53 die steel. The investigated machining parameters were pulse-on time, pulse-off time, pulse-peak current, and wire tension. Analysis of variance (ANOVA) technique was used to find out the parameters affecting the surface roughness. Assumptions of ANOVA were discussed and then examined through residual analysis. Quantitative testing methods on residual analysis were employed in place of the typical qualitative testing techniques.

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  • (BQ) This paper describes the heat source diameter of single pulse discharge in electrical discharge machining. To observe the discharge plasma, SiC and Ga2O3 single crystals were used as the electrode material since they are optically transparent and electrically conductive. It was found that plasma diameter expands within a few microseconds after dielectric breakdown and the plasma diameter is much larger than the discharge crater.

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  • (BQ) Micro and macro EDM are similar, but differences in machining conditions result in a differing power density, Pe. This causes differences in the ratio of energy consumed for material removal with regard to energy distributed into the workpiece, and the ratio of total removal volume per pulse with respect to the molten area volume, so-called energy efficiency, Ee, and removal efficiency, Re, respectively. It was found that, the Pe of micro EDM is approximately 30 times greater than that of macro EDM. Consequently, Ee and Re in micro EDM were significantly greater than those of macro EDM.

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  • (BQ) ilicon infiltrated silicon carbide (SiSiC) is developed. The influences of the major operating EDM parameters (discharge current ie, open gap voltage ui, discharge duration te and pulse interval to) of the iso energetic generator on the machining performances like Material Removal Rate (MRR), Tool Wear Ratio (TWR) and surface roughness (Ra) are examined. Relaxation pulses which have lower energy input are also considered to improve the surface quality.

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  • (BQ) This paper presents an investigation of the effects of machining variables on the surface roughness of wire-EDMed DC53 die steel. In this study, the machining variables investigated were pulse-peak current, pulse-on time, pulse-off time, and wire tension. Analysis of variance (ANOVA) technique was used to find out the variables affecting the surface roughness. Assumptions of ANOVA were discussed and carefully examined using analysis of residuals. Quantitative testing methods on residual analysis were used in place of the typical qualitative testing techniques.

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  • Overall structure of electrical power system is in the process of changing. For incremental growth, it is moving away from fossil fuels - major source of energy in the world today - to renewable energy resources that are more environmentally friendly and sustainable [1].

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  • Energy Storage edited by Md. Rafiqul Islam Sheikh SCIYO .Energy Storage Edited by Md. Rafiqul Islam Sheikh Published by Sciyo Janeza Trdine 9, 51000 Rijeka, Croatia Copyright © 2010 Sciyo All chapters are Open Access articles distributed under the Creative Commons Non Commercial Share Alike Attribution 3.0 license, which permits to copy, distribute, transmit, and adapt the work in any medium, so long as the original work is properly cited.

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