This document presents a seminar report on dry and near dry electrical discharge machining (EDM). EDM uses electric sparks to erode material away from a conductive workpiece. Dry EDM replaces the liquid dielectric fluid with gas, which avoids issues with liquid fluids but causes lower material removal rates and tool overheating. Near dry EDM uses a liquid-gas mixture as the dielectric to improve material removal rates over dry EDM while avoiding debris deposition issues of wet EDM. The document discusses the EDM process, developments in dry and near dry EDM, their applications in prototype production and broken tool removal, and concludes that near dry EDM improves performance issues of dry EDM.

1. PRESENTATION ON
SEMINAR REPORT
DRY and NEAR DRY EDM
PRESENTED BY
-: KOLEKAR PRAJIT TANAJI:-
DEPARTMENT OF MECHANICAL ENGINEERING

2. Contents
Introduction
EDM Process
Dry EDM
NEAR Dry EDM
Application
Conclusion
Reference

3. What is EDM?
Electrical Discharge Machining.
Used on Hard material.
Works with electrically conductive
material.
Material of any hardness can be cut.

4. How EDM Works?
 Uses Very Powerful sparks.
 Series rapidly recurring
charges.
 Remove excess by fluid flow.

5. Development in EDM
Process
Wet EDM Process.
Dry EDM Process.
Near dry EDM Process.

6. Dry Electric Discharge
Machining
 Liquid fluid is replaced by gaseous dielectric
fluid.
 In 1985 NASA used first.
 Kunieda is showing that improve MRR, by
using oxygen gas.
 Debris deposition and low MRR are two
problems in DEDM.

7. Dry Electric Discharge
Machining
No cutting fluid is used.
 Avoid problems of cutting fluid,
contamination, disposal, and filtration.
Problem with dry machining
 Overheating of the tool.
 Operating at lower cutting speeds and
production rates to prolong tool life

8. Dry Electrical Discharge
Machining

9. Near Dry EDM
 NDEDM uses liquid-gas mixture.
 NDEDM shows advantages over WEDM
and DEDM.
 No debris deposition is observed.
 High water flow rate increases high
MRR.

10. Near Dry EDM
For drilling 1.27 mm thick Al6061 rod.
Dry EDM Wet EDM Near dry EDM
428 s 11 s 13 s

11. Application
[1] Prototype production
 The EDM process is most widely used by the
mould making tool and die industries, but it is
common method of making prototype and
production parts, easipcally in the aerospace,
automobile and electronics industries in which
production quantities are relatively low.

12. Application cont.
[2] Metal disintegration machining
 Several manufacturing produce EDM
machines for the specific purpose of
removing broken tools from work piece.
In this application the process is termed
metal disintegration machining.

13. Conclusion
 From this study the contribution of EDM to industries such
as cutting new hard materials make EDM technology
remains indispensable.
 EDM has brought many improvements in machining
process in recent years.
 The Dry EDM with compressed gases is also not
harmful for the system operators.
 Near dry EDM improved the MRR and eliminated the
problem of debris deposition.
 During experimentation, it was observed that near-dry
EDM does not produce health hazards.

14. References
[1] Fabio N. LeaO, Ian R. Pashby @2003 “A review on
the use of environmentally-friendly dielectric fluids in
electrical discharge machining” School of Mechanical,
Materials, Manufacturing Engineering and Management,
University of Nottingham,
University Park, Nottingham NG7 2RD, UK.
[2] C.C. Kao, Jia Tao, Sangwon Lee, and Albert J. Shih
@2010 “Dry Wire Electrical Discharge Machining of Thin
Workpiece” Mechanical Engineering University of
Michigan
Ann Arbor, MI 48109
[3]Sang Won Lee and Young Seok Oh @2008 “A Study
on Dry Electrical Discharge Machining Process” School of
Mechanical Engineering, Sungkyunkwan University,
Suwon, Korea.

15. References
[4] Govindan Puthumana and Suhas S. Joshi @2011
“Investigations into Performance of Dry EDM Using
Slotted Electrodes” Department of Mechanical
Engineering, Indian Institute of Technology
Bombay, Mumbai, India.
[5] C.C. Kao, Jia Tao, Albert J. Shih @2007 “Near dry
electrical discharge machining” Mechanical
Engineering,
University of Michigan, Ann Arbor, MI 48109, USA.
[6] Krishnakant Dhakar, Akshay Dvivedi @2014
“Experimental Investigation on Near-dry Electric
Discharge
Machining” Mechanical & Industrial Engineering
Department, IIT Roorkee, Uttarakhand.