This study investigates the dry and near-dry electrical discharge machining (EDM) milling to achieve a high material removal rate (MRR) and fine surface finish for roughing and finishing operations, respectively. Dry EDM uses gas and near-dry EDM applies a liquid-gas mixture as the dielectric medium. Experimental studies leading to the selection of oxygen gas and copper electrode for high MRR dry EDM and the nitrogen-water mixture and graphite electrode for fine surface finish near-dry EDM are presented. Near-dry EDM exhibits the advantage of good machining stability and surface finish under low discharge energy input. A 251 fractional factorial design is applied to investigate the effect of discharge current, pulse duration, and pulse interval on the MRR and surface finish in dry and near-dry EDMs. Lower pulse duration and lower discharge current are identified as key factors for improving the surface finish in near-dry EDM.

1.
NASA, 1984, “
Inert-Gas Electrical-Discharge Machining
,” NASA Technical Brief No. NPO-15660.
2.
Kunieda
,
M.
, and
Yoshida
,
M.
, 1997, “
Electrical Discharge Machining in Gas
,”
CIRP Ann.
0007-8506,
46
(
1
), pp.
143
146
.
3.
Kunieda
,
M.
, and
Furudate
,
C.
, 2001, “
High Precision Finish Cutting by Dry WEDM
,”
CIRP Ann.
0007-8506,
50
(
1
), pp.
121
124
.
4.
Kunieda
,
M.
,
Miyoshi
,
Y.
,
Takaya
,
T.
,
Nakajima
,
N.
,
Yu
,
Z. B.
, and
Yoshida
,
M.
, 2003, “
High Speed 3D Milling by Dry EDM
,”
CIRP Ann.
0007-8506,
52
(
1
), pp.
147
150
.
5.
Kao
,
C. C.
,
Tao
,
J.
,
Lee
,
S. W.
, and
Shih
,
A. J.
, 2006, “
Dry Wire Electrical Discharge Machining of Thin Workpiece
,”
Trans. NAMRI/SME
1047-3025,
34
, pp.
253
260
.
6.
Tanimura
,
T.
,
Isuzugawa
,
K.
,
Fujita
,
I.
,
Iwamoto
,
A.
, and
Kamitani
,
T.
, 1989, “
Development of EDM in the Mist
,”
Proceedings of Ninth International Symposium of Electro Machining (ISEM IX)
, Nagoya, Japan, pp.
313
316
.
7.
Kao
,
C. C.
,
Tao
,
J.
, and
Shih
,
A. J.
, 2007, “
Near Dry Electrical Discharge Machining
,”
Int. J. Mach. Tools Manuf.
0890-6955,
47
(
15
), pp.
2273
2281
.
8.
Kunieda
,
M.
,
Lauwers
,
B.
,
Rajurkar
,
K. P.
, and
Schumacher
,
B. M.
, 2005, “
Advancing EDM Through Fundamental Insight Into the Process
,”
CIRP Ann.
0007-8506,
54
(
2
), pp.
599
622
.
9.
Shugg
,
W. T.
, 1986,
Handbook of Electrical and Electronic Insulating Materials
,
Van Nostrand Reinhold
,
New York
, pp.
230
234
.
10.
Yaws
,
C. L.
, 1995,
Handbook of Transport Property Data: Viscosity, Thermal Conductivity, and Diffusion Coefficients of Liquids and Gases
,
Gulf
,
Houston, TX
, pp.
192
193
.
11.
Avallone
,
E. A.
, and
Baumeister
,
T.
, 1996,
Standard Handbook for Mechanical Engineers
,
10th ed.
,
McGraw-Hill
,
New York
, pp.
4
82
.
12.
Vedensky
,
B. A.
, and
Vul
,
B. M.
, 1965,
Encyclopedia Dictionary in Physics 4
,
Soviet Encyclopedia
,
Moscow
, p.
240
.
13.
Gerasimov
,
A. I.
, 2005, “
Water as an Insulator in Pulsed Facilities
,”
Instrum. Exp. Tech.
0020-4412,
48
(
2
), pp.
141
167
.
14.
Peyton
,
K. B.
, 2002,
Ondeo/Nalco Fuel Field Manual
,
McGraw-Hill
,
New York
, p.
112
.
15.
Forsythe
,
W. E.
, 2003,
Smithsonian Physical Tables
,
Knovel, Norwich
,
NY
, p.
322
.
16.
Incropera
,
F. P.
, and
DeWitt
,
D. P.
, 2007,
Introduction to Heat Transfer
,
5th ed.
,
Wiley, Hoboken
,
NJ
, pp.
102
111
.
17.
Yang
,
D. Y.
, and
Cao
,
F. G.
, 2007, “
The Development of Mirror Machining in EDM Sinking Process
,”
Proceedings of 15th International Symposium of Electro Machining (ISEM XV)
,
Industrial and Management Systems Engineering, Pittsburgh
,
PA
, pp.
57
62
.
18.
Hockenberry
,
T. O.
, and
Williams
,
E. M.
, 1967, “
Dynamic Evolution of Events Accompanying the Low-Voltage Discharge Employed in EDM
,”
IEEE Trans. Ind. Gen. Appl.
0018-943X,
3
(
4
), pp.
302
309
.
19.
Koenig
,
W.
,
Wertheim
,
R.
,
Zvirin
,
Y.
, and
Toren
,
M.
, 1975, “
Material Removal and Energy Distribution in Electrical Discharge Machining
,”
CIRP Ann.
0007-8506,
24
(
1
), pp.
95
100
.
20.
Yan
,
B. H.
,
Tsai
,
H. C.
, and
Huang
,
F. Y.
, 2005, “
The Effect in EDM of a Dielectric of a Urea Solution in Water on Modifying the Surface of Titanium
,”
Int. J. Mach. Tools Manuf.
0890-6955,
45
(
2
), pp.
194
200
.
21.
Kunieda
,
M.
, and
Furuoya
,
S.
, 1991, “
Improvement of EDM Efficiency by Supplying Oxygen Gas Into Gap
,”
CIRP Ann.
0007-8506,
40
(
1
), pp.
215
218
.
22.
Carrano
,
A. L.
,
Mehta
,
B.
, and
Low
,
J. C.
, 2004, “
Response Surface Methodology of Die-Sink Electro-Discharge Machined Surfaces
,”
IIE Annual Conference and Exhibition, Institute of Industrial Engineers
, Houston, TX, pp.
787
792
.
23.
Luis
,
C. J.
,
Puertas
,
I.
, and
Villa
,
G.
, 2005, “
Material Removal Rate and Electrode Wear Study on the EDM of Silicon Carbide
,”
J. Mater. Process. Technol.
0924-0136,
164–165
(
15
), pp.
889
896
.
24.
Puertas
,
I.
,
Luis
,
C. J.
, and
Villa
,
G.
, 2005, “
Spacing Roughness Parameters Study on the EDM of Silicon Carbide
,”
J. Mater. Process. Technol.
0924-0136,
164–165
(
15
), pp.
1590
1596
.
25.
Luo
,
Y. F.
, 1997, “
Dependence of Interspace Discharge Transitivity Upon the Gap Debris in Precision Electrodischarge Machining
,”
J. Mater. Process. Technol.
0924-0136,
68
(
2
), pp.
121
131
.
26.
Luo
,
Y. F.
, and
Chen
,
C. G.
, 1990, “
Effect of a Pulsed Electromagnetic Field on the Surface Roughness in Superfinishing EDM
,”
Precis. Eng.
0141-6359,
12
(
2
), pp.
97
100
.
27.
Schumacher
,
B. M.
, 1987, “
EDM Technology for Precision Workpieces With Excellent Surface Quality
,”
Proceedings of the 7th International Symposium of Electro Machining (ISEM VII)
, IFS Ltd., Birmingham, UK, pp.
124
135
.
You do not currently have access to this content.