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Transcript of suvendu banerjee(14mt000107)
DEVELOPMENT OF WIRE ELECTRICAL DISCHARGE TURNING SETUP AND ITS APPLICATION FOR FABRICATION OF PREFORMED FOR MICRO TOOL
NAME:-SUVENDU BANERJE ADM NO:-14MT000107
MANUFACTURING(M.TECH)
GUIDED BY:-DR.AMIT RAI DIXIT
OUTLINE:- INTRODUCTION LITERATURE REVIEW OBJECTIVES EXPERIMENTATION RESULT AND DISCUSIONS COCLUSIONS SCOPE FOR FUTURE WORK
INTRODUCTION- In WEDM process, the material is eroded ahead of the wire due to the
thermoelectric sparks generated between the work piece and the electrode. In this process the work piece experiences no mechanical stresses due to no direct contact between the work piece and the wire makes the process widely employed to cut the electrically conductive hard-to-cut material with irrespective of its hardness and strength .
Fig:-Concept of Wire Electrical Discharge Machining
Wire electrical discharge turning (turning with WEDM) is one of the emerging area, developed to generate cylindrical form on hard and difficult to cut super alloys such as Titanium and Nickel. In WEDT process the electrical discharge takes place between the traveling wire and the rotating work piece (a rotary axis is added to WEDM) to be machined. In this process the desired cylindrical forms can be obtained by controlling the electrically charged wire in X and Y directions to remove the unwanted work material.
FIG:- Concept of Wire Electrical Discharge Turning
LITERATURE REVIEWAuthor and Year of publication
Material Process parameters
Output parameters
Methodology Remarks
Dr Masuzaw 2000
Microelectrode tool
- - - Cylindrical pins - 5 µm in diameter machined
Qu et. al. 2001 a
Carbide and Brass (2D and cylindrical)
Wire feed rate, Part rotation speed
Spindle error analysis, MRR in 2D and CWEDT
Donaldson reversal principle for spindle error analysis
MRRWEDT>MRRWEDM
BrassMRR > Tungsten CarbideMRR
Qu et. al. 2001 b
Pulse On time, wire feed rate and part rotational speed
MRR for rough and good surface finish, Surface roughness
SEM for measuring surface roughness.
Higher RPM & slower Vf generated smaller pitch and lower RaAchieved Surface Roughness: 0.68 µm
Mohammadi et. al. 2007
Cemented steel
Power, Time Off, Voltage, Servo volt, Wire tension, wire speer, RPM
Surface roughness, Roundness
L18 (21×37) Taguchi standard orthogonal array
power has a significant effect on the surface roughnessThe effects of wire speed, power, and servo on roundness are more significant than time-off, voltage, wire tension, and rotational speed.
Author and Year of publication
Material Process parameters
Output parameters
Methodology Result
M J haddad et. al. 2009
AISI D3 Tool steel
Power, Voltage, Pulse off time, RPM
Surface roughness, Surface roundness, Recast layer.
Taguchi method, SEM for measuring surface integrity
Under High MRR – Recast layer 40-50 µm, HAZ 20-25 µmUnder low MRR – Recast layer 15-20 µm, HAZ 8-13 µmPower and Voltage
Naresh baki et. al. 2014
TI-6AL-4V Alloy
RPM, ToN, ToFF, Peak current, Wire feed, Servo volt
Surface roughness and MRR
DOE: Taguchi methodOptimization: Gray Relational analysis
Optimal combination: RPM 30, ToN 10 µs, ToFF 50 µs, Peak current 150A, Wire feed 3mm/min, Servo 90VSignificant Parameters: RPM, ToN and Servo.
Balamurali et. al. 2015
Stainless Steel 316
Gap volt, ToN, ToFF, Wire speed, RPM
MRR, Surface roughness
Taguchi method L27
Gap V decrease MRR increase Ra decrease, ToN increase MRR increase Ra increase, ToFF increase MRR increase Ra decrease, RPM increase MRR & Ra increase
OBJECTIVES:- To develop WIRE ELECTRICAL DISCHARGE TURNING
(WEDT) setup on conventional WEDM system.
Investigation of input parameters of WEDT on output response.
Application of WEDT for fabrication of preformed for micro
tool.
Development of preformed for MICRO ECM, MICRO EDM
EXPERIMENTATION:-
The experiments are conducted on a high precision 4- axis CNC
WEDM . The wire EDM machine was equipped with a rotary axis in order to
produce cylindrical forms. TUNGSTEN work piece of 1mm diameter with
6mm length was used to perform the turning experiments on WEDM
Conventional design:-
wire used – Zinc coated brass wire of 0.25 mm
Dielectric – Deionized water
Process parameters – Spindle rotation speed, Voltage, Depth of cut
Output parameter – Diameter Deviation, Surface Roughness, Surface Waviness
Design of experiment - Taguchi L9 (34)Orthogonal Array Design
MICRO EDM and MICRO ECM were done on the preformed tool
Fig:- Schematic Of WEDT Setup Fig:- Actual WEDT Setup
Fig:- WEDT Operation Fig:-Specimen After Cut
MACHINED SURFACE
Fig:-Workpiece After MICRO ECMFig:-MICRO ECM Operation
Fig:-MICRO EDM Operation Fig:-Workpiece After MICRO EDM
RESULTS AND DISCUSSION
L9 (34) Taguchi standard orthogonal array, factors and factor levels were selected for
determining optimal process setting conditions, significant factors, and their
interactions.
After performing the experiments successfully the work-pieces final diameter,
roughness value (Ra) and waviness (Wa) values were measured in optical microscope
After getting all the dimensions the diameter deviation (∆d) is being calculated by
using the following equation
∆d= (Theoretical diameter) – (Actual Diameter) =Dtheo - Dact
Theoretical diameter = (Blank Size) – (2* Depth of Cut)
Actual Diameter = The diameters taken along the machined surface
Diameter deviation = mean of ∆d
Sl
No.
Spindle
Rotational
Speed
(rpm)
Gap
Voltage
(V)
Depth
Of Cut
(mm)
Diameter
Deviation
(∆d)(μm)
Surface
Roughness
(Ra)(μm)
Surface
Waviness
(Wa)
(μm)
SNRA1 SNRA2 SNRA3
1 30 30 0.300 74.13 0.46 1.49 -37.3999 6.744843 -3.46373
2 30 50 0.325 39.77 0.98 1.97 -31.9911 0.175478 -5.88932
3 30 70 0.350 145.94 0.47 1.73 -43.2835 6.558043 -4.76092
4 400 30 0.325 158.68 1.35 2.27 -44.0104 -2.60668 -7.12052
5 400 50 0.350 56.7 0.72 2.47 -35.0717 2.85335 -7.85394
6 400 70 0.300 187.06 0.34 1.49 -45.4396 9.370422 -3.46373
7 770 30 0.350 37.955 0.75 2.8 -31.5854 2.498775 -8.94316
8 770 50 0.300 23.353 0.36 1.78 -27.3669 8.87395 -5.0084
9 770 70 0.325 212.845 0.3 1.29 -46.5613 10.45757 -2.21179
Table-Experimental Result
SNRA= Signal To Noise Ratio
ANALYSIS OF THE OUTPUT RESPONSES:-Diameter Deviation(∆d):- Surface Roughness (Ra):-
Surface Waviness (Wa):-
The result of the three tests which were performed in WEDT is given below:
Sl
No.
Spindle
Rotational
Speed
(rpm)
Gap
Voltage
(V)
Depth
Of
Cut
(mm)
Diameter
Deviation
(∆d) (μm)
Surface
Roughness
(Ra) (μm)
Surface
Waviness
(Wa) (μm)
∆d1 ∆d2 ∆d3 Ra1 Ra2 Ra3 Wa1 Wa2 Wa3
1 400 50 0.3 68.11 120.32 79.495 1.06 1.145 1.385 3.75 3.235 4.54
MICROSCOPIC IMAGES OF WEDT MACHINED SURFACES :-
Fig: Texture Surface Fig :3D Surface withTexture
MICRO EDM OPERATION
VOLTAGE
(V)
PULSE
WIDTH/
TON(μs)
SPEED
(rpm)
Final Diameter
Surface roughness (Ra)(μm)
Surface Waviness(Wa)(μm)
40 40 5000 294μm 1.3 μm 3.1μm.
MICROSCOPIC IMAGES
Fig: Texture Surface Fig: 3D Surface With Texture
VOLTAGE
(V)
FREQUENC
Y
(Hz)
PULSE
WIDTH
(TON)
DUTY Final Diameter(μm)
Surface Roughness(Ra)(μm)
Surface Waviness(Wa) (μm)
10 10000 10 10 140 0.36 1.6
MICRO ECM OPERATION
MICROSCOPIC IMAGES
Fig:Texture Surface Fig: 3D Surface with Texture
FESEM IMAGES OF WEDT MACHINED SUREFACE
FESEM IMAGES OF MICRO EDM MACHINED SURFACE
LENGTH WISE PORTION
TOP PORTION
FESEM IMAGES MICRO ECM MACHINED SURFACE
Fig : Length Wise Fig: Top Portion
DEPOSITED ELEMENTS AND THEIR COMPOSITIONElement Weight% Atomic%
W M 82.88 27.79
C K 4.90 25.13
O K 12.22 47.08
Element Weight% Atomic%W M 59.87 10.86C K 17.96 49.87O K 17.19 35.83Na K 1.15 1.67Cl K 1.14 1.07K K 0.45 0.38Th M 2.25 0.32
WEDT MACHINED SURFACE
BLANK SURFACE
Element Weight% Atomic%W M 27.18 2.96C K 30.54 50.97O K 31.74 39.76Na K 1.50 1.31Al K 2.65 1.97S K 0.21 0.13Cl K 1.27 0.72K K 1.29 0.66Ca K 0.47 0.24Ti K 2.76 1.15Fe K 0.39 0.14
Element Weight% Atomic%W M 68.14 15.14C K 16.51 56.14O K 9.92 25.32Na K 0.60 1.07Cl K 0.40 0.46K K 1.26 1.32Th M 3.17 0.56
MICRO EDM Machined Surface
MICRO ECM Machined Surface
COCLUSIONS
It was observed after MICRO EDM operation that the diameter of one of the preformed tool reduced only 30μm in 1hr 5 minutes.
It was observed after MICRO ECM operation that the diameter of one of the preformed tool reduced 150μm in 5 minutes
It was observed craters, spherical nodules, globules of debris ,coral reef and micro cracks in both machined surface of WEDT and MICRO EDM
Cracks are being generated due to thermal and tensile stress. The nature of the cracks is due to the deionized water
In the MICRO ECM machined surface all shallow craters, globules of debris, and pockmarks formed by entrapped gases escaping from the re-deposited material reduced to a great amount
SCOPE FOR FUTURE WORK
Diameter of the tool can also be reduced less than 100μm by using those combining techniques
The issues such as residual stress after machining with WEDT may be investigated.
The issue of eccentricity after machining with WEDT may be investigated on the existed WEDM setup
The research work could be further extended over a variety of exotic advanced materials.
The possible use of cryogenic treated wire electrode for machining of nonconductive and composite materials (Ceramic, fiberglass etc.) could also be investigated