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1

The optimization of micro-EDM machining process when using carbon coated micro electrode as a tool

Mac Thi Bich, Shirguppikar Shailesh, Ganachari Vaibhav

Journal of Machine Engineering

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2023

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Vol. 23, No. 2

186--197

EN

The amount of electrode wear in micro-EDM has a direct effect on the dimensional accuracy of the machined hole. Therefore, improving the corrosion resistance of electrodes in micro-EDM is still of great interest. The effective coating of thin film for the micro tool electrodes in the case of micro-EDM can lead to minimize the electrode wear which eventually improve the productivity and machining quality. In the present study, experiments were performed on micro-EDM using carbon coated tool electrode and optimized using Taguchi-Topsis to investigate optimum levels of Depth of cut (Z) and overcut (OVC). It was concluded that optimum conditions had improved significantly using carbon coated micro tool electrode. Optimal levels of technological parameters include V = 160 V, C = 10000 pF, RPM = 600 rpm, and Zopt = 2.525 mm, OVCopt = 65.257 µm. The quality of the machined surface with the coated electrode at optimal conditions is analysed and evaluated. The Topsis method is a suitable solution to this problem, and the steps to perform the calculation in this technique are simple.

2

On Micromachining with a Focus on Miniature Gears by Non Conventional Processes. A Status Report

Chaudhary T., Siddiquee A. N., Chanda A. K., Khan Z. A.

Archive of Mechanical Engineering

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2018

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Vol. LXV, nr 1

129--169

EN

Recent developments in automation and technology have revolutionized the way products are made. It is directly seen in the evolution of part miniaturization in the sectors such as aerospace, electronics, biomedicine and medical implants. Micromachining is a promising technology to fulfill the need of miniaturization. A review has been done on the micromachining processes such as micro electric discharge machining (micro-EDM) and wire EDM (WEDM), micro electrochemical machining (micro-ECM). Recent literature were studied and categorized in terms of materials, process parameters, performances, product manufactured, and miniature product generation. Starting with brief introduction to micromachining, classifications and applications, technical aspects of discussions from the literature have been presented on key factors such as parameters and the response variables. Important aspects of recast layer, heat effected zone, micro-hardness, micro cracks, residual stress, etc., have been given. A special focus is given to the status of the research on microgear manufacturing. Comparison has been made between other conventional process suitable for micro-gear manufacturing and WEDM. The miniature gear machined by WEDM shows the defect-free microstructure, better surface finish, thin recast layer and improved gear quality parameters such as profile and pitch. Finally, the research gaps and future research directions have been presented.

3

An Influence of Parameters of Micro-electrical Discharge Machining on Wear of Tool Electrode

Puthumana G.

Archive of Mechanical Engineering

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2017

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Vol. LXIV, nr 2

149--163

EN

To achieve better precision of features generated using the micro-electrical discharge machining (micro-EDM), there is a necessity to minimize the wear of the tool electrode, because a change in the dimensions of the electrode is reflected directly or indirectly on the feature. This paper presents a novel modeling and analysis approach of the tool wear in micro-EDM using a systematic statistical method exemplifying the influences of capacitance, feed rate and voltage on the tool wear ratio. The association between tool wear ratio and the input factors is comprehended by using main effect plots, interaction effects and regression analysis. A maximum variation of four-fold in the tool wear ratio have been observed which indicated that the tool wear ratio varies significantly over the trials. As the capacitance increases from 1 to 10 nF, the increase in tool wear ratio is by 33%. An increase in voltage as well as capacitance would lead to an increase in the number of charged particles, the number of collisions among them, which further enhances the transfer of the proportion of heat energy to the tool surface. Furthermore, to model the tool wear phenomenon, a regression relationship between tool wear ratio and the process inputs has been developed.

4

Zastosowanie metod statystycznych do monitorowania procesu obróbki elektroerozyjnej elektrodą drutową

Nowakowski A., Majerski P.

Inżynieria Maszyn

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2011

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R. 16, z. 3

24-31

PL

Dla potrzeb monitorowania procesów wycinania i mikrowycinania elektroerozyjnego opracowano modele statystyczne wykorzystujące mechanizm średniej kroczącej. W przypadku wycinania średnia krocząca opisuje proces zmian wartości czasu opóźnienia wyładowań. Przy mikrowycinaniu średnia krocząca śledzi proces ewolucji wybranych trzech typów impulsów napięcia międzyelektrodowego. Przedstawione metody mogą być wykorzystane zarówno do kontroli przebiegu procesów WEDM jak i mikro-WEDM. Modele zweryfikowano w trybie off-line, wykorzystując zrejestrowane ciągi impulsów napięcia międzyelektrodowego oraz podczas obróbki, implementując go w mikroprocesorowych analizatorach procesu.

EN

The paper presents investigations of the WEDM and micro-WEDM processes degeneration, carried out with MEDIOS-20 and the experimental micro-WEDM machine MW50 type developed in IZTW. The measuring stand consisted of the WEDM machines connected with the gap voltage pulses analysers, the data logger, the PC computer with the dedicated software for data acquisition and processing. The main tool used for prediction of the both processes degeneration was the moving average (MA) model, endowed with a parameter q, which plays a role of a smoothing parameter as well as a 'memory' window. During the WEDM machining the subject of the analysis was the delay time of discharges. In the micro-WEDM process the data input for the model was the transient numerical time series received from the gap voltage discriminating system, which separated the gap voltage pulses into three classes: idle, normal and short, according to their amplitude before discharge and the voltage drop during discharge. During the analysis it has been observed, that very often the MA for the degenerated processes decreased just before the wire braking, whereas this almost never happened for the stable one. Algorithms calculated the on-line process degradation level (WZ) were derived from the above model. The off-line verification of the presented models, performed with the registered data, showed their good reliability. The algorithm was both applied in a microprocessor controller and verified on-line during the machining.