INFLUENCE OF VOLTAGE AND WIRE SPEED ON FORMING THE MACHINED SURFACE ROUGHNESS DURING WIRE ELECTRICAL DISCHARGE MACHINING

Shape-memory alloys such as nitinol are gaining popularity as advanced materials in the aerospace, medical, and automobile sectors. However, nitinol is a difficult-to-cut material because of its versatile specific properties such as the shape-memory effect, superelasticity, high specific strength, high wear and corrosion resistance, and severe strain hardening. Anunconventional machining process like wire-electrical-discharge-machining (WEDM) can be effectively and efficiently used for the machining of such alloys, although the WEDM-induced surface integrity of nitinol hassignificant impact on material performance. Therefore, this work investigated the surface integrity of WEDM-processed nitinol samples using digital microscopy imaging, scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) analysis. Three-dimensional analysis of the surfaces was carried out in two different patterns (along the periphery and the vertical plane of the machined surface) andrevealed that surface roughness was maximalat the point where the surface was largely exposed to the WEDM dielectric fluid. To attain the desired surface roughness, appropriate discharge energy is required that, in turn, requires the appropriate parameter settings of the WEDM process. Different SEM image analyses showed a reduction in microcracks and pores, and in globule-density size at optimized parameters. EDX analysis revealed the absence of wire material on the machined surface

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Influence of Gap Phenomenon on Various Kinds of Powder-Suspended EDM

International Journal of Automation Technology ◽

10.20965/ijat.2013.p0419 ◽

2013 ◽

Vol 7 (4) ◽

pp. 419-425

Author(s):

Hideki Takezawa ◽

◽

Tadashi Asano ◽

Naotake Mohri ◽

◽

...

Keyword(s):

Surface Roughness ◽

Electrical Discharge ◽

High Speed ◽

Electrical Discharge Machining ◽

High Speed Camera ◽

Machined Surface ◽

Machined Surface Roughness ◽

Observation Results

Powder-suspended Electrical Discharge Machining (EDM) produces a mirror-like finish due to the electrical discharge dispersed using powder-suspended fluid. Machined surface roughness differed, however, when several powders are mixed, so the influence of the gap phenomenon was not apparent. To vary the gap phenomenon in powder-suspended EDM, the gap region is observed using a high-speed camera. This report describes observation results in powdersuspended EDM.

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Surface Modification Using Assisting Electrodes in Wire Electrical Discharge Machining for Silicon Wafer Preparation

Materials ◽

10.3390/ma14061355 ◽

2021 ◽

Vol 14 (6) ◽

pp. 1355

Author(s):

Chunliang Kuo ◽

Yupang Nien ◽

Anchun Chiang ◽

Atsushi Hirata

Keyword(s):

Surface Roughness ◽

Surface Modification ◽

Electrical Discharge ◽

Polycrystalline Silicon ◽

Material Removal ◽

Electrical Discharge Machining ◽

Wire Electrical Discharge Machining ◽

Electrode Thickness ◽

Machined Surface ◽

Pulse On Time

This paper outlines notable advances in the wire electrical discharge machining of polycrystalline silicon workpieces for wafer preparation. Our use of assisting electrodes permits the transfer of aluminum particles to the machined surface of the polycrystalline silicon workpieces, to enhance conductivity and alter surface topography regardless of the silicon’s crystallographic structure and diamond-type lattice. This in-process surface modification technique was shown to promote material removal and simultaneously preserve the integrity of the machined surfaces with preferable surface textures. In the validation experiment, the 25 mm-thick assisting electrodes deposited a notable concentration of aluminium on the machined surface (~3.87 wt %), which greatly accelerated the rate of material removal (~9.42 mg/s) with minimal surface roughness (Sa ~5.49 μm) and moderate skewness (−0.23). The parameter combination used to obtain the optimal surface roughness (Sa 2.54 μm) was as follows: open voltage (80 V), electrical resistance (1.7 Ω), pulse-on time (30 μs), and electrode thickness (15 mm). In multiple objective optimization, the preferred parameter combination (open voltage = 80 V, resistance = 1.4 Ω, pulse-on time = 60 μs, and assisting electrode thickness = 25 mm) achieved the following appreciable results: surface modification of 3.26 ± 0.61 wt %, material removal rate of 7.08 ± 2.2 mg/min, and surface roughness of Sa = 4.3 ± 1.67 μm.

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Studies of kerf width and surface roughness using the response surface methodology in AA 4032–TiC composites

Proceedings of the Institution of Mechanical Engineers Part E Journal of Process Mechanical Engineering ◽

10.1177/09544089211041418 ◽

2021 ◽

pp. 095440892110414

Author(s):

TS Senthilkumar ◽

R Muralikannan ◽

T Ramkumar ◽

S Senthil Kumar

Keyword(s):

Surface Roughness ◽

Response Surface Methodology ◽

Response Surface ◽

Metal Matrix ◽

Electrical Discharge ◽

Electrical Discharge Machining ◽

Kerf Width ◽

Wire Electrical Discharge Machining ◽

Box Behnken Design ◽

Pulse On Time

A substantially developed machining process, namely wire electrical discharge machining (WEDM), is used to machine complex shapes with high accuracy. This existent work investigates the optimization of the process parameters of wire electrical discharge machining, such as pulse on time ( Ton), peak current ( I), and gap voltage ( V), to analyze the output performance, such as kerf width and surface roughness, of AA 4032–TiC metal matrix composite using response surface methodology. The metal matrix composite was developed by handling the stir casting system. Response surface methodology is implemented through the Box–Behnken design to reduce experiments and design a mathematical model for the responses. The Box–Behnken design was conducted at a confident level of 99.5%, and a mathematical model was established for the responses, especially kerf width and surface roughness. Analysis of variance table was demarcated to check the cogency of the established model and determine the significant process. Surface roughness attains a maximum value at a high peak current value because high thermal energy was released, leading to poor surface finish. A validation test was directed between the predicted value and the actual value; however, the deviation is insignificant. Moreover, a confirmation test was handled for predicted and experimental values, and a minimal error was 2.3% and 2.12% for kerf width and surface roughness, respectively. Furthermore, the size of the crater, globules, microvoids, and microcracks were increased by amplifying the pulse on time.

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Surface Roughness at Wire Electrical Discharge Machining

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.760.551 ◽

2015 ◽

Vol 760 ◽

pp. 551-556 ◽

Cited By ~ 1

Author(s):

Oana Dodun ◽

Laurenţiu Slătineanu ◽

Margareta Coteaţă ◽

Vasile Merticaru ◽

Gheorghe Nagîţ

Keyword(s):

Surface Roughness ◽

Empirical Model ◽

Electrical Discharge ◽

Electrical Discharge Machining ◽

Roughness Parameter ◽

Wire Electrical Discharge Machining ◽

Power Type ◽

Surface Roughness Parameter ◽

Pulse On Time ◽

Pulse Off Time

Wire electrical discharge machining is a machining method by which parts having various contours could be detached from plate workpieces. The method uses the electrical discharges developed between the workpiece and the wire tool electrode found in an axial motion, when in the work zone a dielectric fluid is recirculated. In order to highlight the influence exerted by some input process factors on the surface roughness parameter Ra in case of a workpiece made of an alloyed steel, a factorial experiment with six independent variables at two variation levels was designed and materialized. As input factors, one used the workpiece thickness, pulse on time, pulse off-time, wire axial tensile force, current intensity average amplitude defined by setting button position and travelling wire electrode speed. By mathematical processing of the experimental results, empirical models were established. Om the base of a power type empirical model, graphical representations aiming to highlight the influence of some input factors on the surface roughness parameter Ra were achieved. The power type empirical model facilitated establishing of order of factors able to exert influence on the surface roughness parameter Ra at wire electrical discharge machining.

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