A microscopic investigation of machining behavior in μED-milling process

Karthikeyan, G.; Garg, Aman; Ramkumar, J.; Dhamodaran, S.

doi:10.1016/j.jmapro.2012.01.003

Cited by 45 publications

(7 citation statements)

References 22 publications

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“…The main effect and interaction effect plots of the EDM parameters for taper are shown in Figure 16. The developed regression model for the taper of the channel as a function of input parameters is represented with an equation (5). Generally, in EDM the issue of taper arises because of the nonuniform penetration of the discharge plasma in the direction of the depth of a channel as the tool electrode moves down.…”

Section: Regression Equationmentioning

confidence: 99%

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A study on geometrical features of electric discharge machined channels on AA6061-4%B₄C composites

Gudipudi

Selvaraj

Chandra

et al. 2020

Measurement and Control

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The aluminum alloy AA6061-4wt.% boron carbide (B4C) particulate metal matrix composites were fabricated by the stir casting method. The die-sinker electric discharge machining was performed to make the rectangular mini channels on these composites. The full factorial experimental design that consists of three input conditions, the current ( I), discharge duration ( T-on), and discharge idle time ( T-off) at three levels each (33 = 27 total runs), was used for experimentation. The volume, V, the taper, θ (along with the depth), the lateral overcut (along the width), and the difference in depth, Δ d (between total depth and depth up to the tapered profile) at entrance and exit cross-sectional profiles of the channel were considered as output responses. The θ, lateral overcut, and Δ d were calculated from the entrance and exit profiles which were obtained by extracting the data points of each channel with the help of an optical profile projector. The computer-aided geometric model was developed to estimate the volume. A set of optimum electric discharge machining parameter levels were identified for maximum V and a minimum of θ, lateral overcut, and Δ d. Analysis of variance was performed to identify the significant parameter and the contribution toward output responses. Results showed that the volume was found to be maximum at higher I (8 A) and lower T-On (25 µs) conditions. The taper was found to decrease with the increase in current but both lateral overcut and Δ d increased. Both I and T-On are found to be the significant parameters affecting both V and Δ d, whereas current is for θ and lateral overcut. In some cases, it was observed that there is a considerable difference in the θ and the lateral overcut values in the entrance and exit portions for the same channel. It is because of the randomly dispersed B4C particles which alter the material removal mechanism.

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Section: Regression Equationmentioning

confidence: 99%

“…Darwish et al 4 used laser beam-based micro-milling to machine the microchannels on Ti-6Al-4V. Karthikeyan et al 5 employed the micro-electric discharge milling of EN 24 steel to machine the microchannels. Ghoshal and Bhattacharyya 6 used electrochemical micro-micromachining to create micro-channel profiles on SS604 grade stainless steel.…”

Section: Introductionmentioning

confidence: 99%

A study on geometrical features of electric discharge machined channels on AA6061-4%B₄C composites

Gudipudi

Selvaraj

Chandra

et al. 2020

Measurement and Control

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“…Molten metal ejected from the electrode can either flow as a secondary fluid or form globules which on subsequent cooling generates spherical particles or debris. [21][22][23] The size and shape of the globules depend on the discharge energy, crater size and amount of molten metal expelled. When the quantity of the expelled molten metal is larger, then it deposits on the nearby surface forming redeposited layer.…”

Section: Effect Of Iegmentioning

confidence: 99%

Dielectric flow observation at inter-electrode gap in micro-electro-discharge-milling process

Mullya

Karthikeyan

2016

Proceedings of the Institution of Mechanical Engineers, Part B:

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The material removal phenomenon of sparking and melting in micro-electro-discharge-milling process occurs at interelectrode gap of dimension less than 50 mm. The behavior of fluid flow properties at inter-electrode gap is not well discussed in the literature and its information will be useful to understand the material flow behavior and tool wear in micro-electro-discharge-milling process. Based on our previous findings, it was well recognized that tool rotation is an inherent part of micro-electro-discharge-milling and directly influences debris flushing and redeposition. Also for a stable machining performance, flow of dielectric will play an important role in flushing away debris from the gap. The objective of this work is to investigate the fluid flow along the inter-electrode gap and to study its effect on debris movement and molten metal redeposition. The fluid flow along the narrow gap of micro-electro-discharge-milling process for different machining conditions is analyzed by computational fluid dynamics simulation. By particle simulation, the effect of different sized particles formed at various positions and their subsequent movement was also analyzed. The computational fluid dynamics analysis results were validated with scanning electron micrographs obtained for various machining conditions of the experiments. The effect of inlet nozzle velocity, tool rotation and size of electrode gap on the dielectric fluid flow was primarily reported and the findings were later superimposed on particle injection velocity to determine the movement of debris along inter-electrode gap. The effect of debris movement on redeposition at workpiece/tool surface and its ejection from inter-electrode gap is recounted.

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“…They found that the electrode tended to change during machining towards a constant shape and that the milled groove was an arc shape. Karthikeyan et al [ 30 ] found that the shape of the electrode end changed after channel machining during a study of micro-EDM milling. They thought that the tool rotation motion was a key factor.…”

Section: Introductionmentioning

confidence: 99%

An Investigation into Accumulative Difference Mechanism in Time and Space for Material Removal in Micro-EDM Milling

Zhang

et al. 2021

Micromachines

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In micro-electrical discharge machining (micro-EDM) milling, the cross-section of the microgroove machine is frequently not an ideal rectangle. For instance, there are arc shapes on the bottom and corners, and the sidewall is not steep. The theoretical explanation for this phenomenon is still lacking. In addition to the tip discharge effect, the essential reason is that there is an accumulative difference in time and space during the shape change process of a tool electrode and the microstructure formation on a workpiece. The process parameters are critical influencing factors that determine this accumulative difference. Therefore, the accumulative difference mechanism in time and space is investigated in this paper, and then a theoretical model is developed to simulate the micro-EDM milling process with a straight-line single path. The simulation results for a cylindrical electrode at the two rotational speeds of 0 (nonrotating) and 300 rpm are compared, while the results for a cylindrical electrode and a square electrode at a rotation speed of 0 are also compared to verify that different process parameters generate accumulative differences in the time and space of material removal. Finally, micro-EDM milling experiments are carried out to verify the simulation model. The maximum mean relative deviation between the microgroove profiles of simulation results and those of experiments is 11.09%, and the profile shapes of simulations and experiments have a good consistency. A comparative experiment between a cylindrical electrode and a hollow electrode is also performed, which further verifies the mechanism revealed in the study. Furthermore, the cross-section profile of a microgroove can be effectively controlled by adjusting the process parameters when utilising these accumulative differences through fabricating a microgroove with a V-shaped cross-section by a square electrode and a microgroove with a semi-circular cross-section by a cylindrical electrode. This research provides theoretical guidance for solving the problems of the machining accuracy of detail features in micro-EDM milling, for instance, to machine a microgroove with an ideal rectangular cross-section.

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A microscopic investigation of machining behavior in μED-milling process

Cited by 45 publications

References 22 publications

A study on geometrical features of electric discharge machined channels on AA6061-4%B₄C composites

A study on geometrical features of electric discharge machined channels on AA6061-4%B₄C composites

Dielectric flow observation at inter-electrode gap in micro-electro-discharge-milling process

An Investigation into Accumulative Difference Mechanism in Time and Space for Material Removal in Micro-EDM Milling

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A microscopic investigation of machining behavior in μED-milling process

Cited by 45 publications

References 22 publications

A study on geometrical features of electric discharge machined channels on AA6061-4%B4C composites

A study on geometrical features of electric discharge machined channels on AA6061-4%B4C composites

Dielectric flow observation at inter-electrode gap in micro-electro-discharge-milling process

An Investigation into Accumulative Difference Mechanism in Time and Space for Material Removal in Micro-EDM Milling

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A study on geometrical features of electric discharge machined channels on AA6061-4%B₄C composites

A study on geometrical features of electric discharge machined channels on AA6061-4%B₄C composites