In Electro Discharge Machining(EDM) ,the metal removal is based on thermal principles involving the application of very intense local heat have come into use in recent years. In this process, material is removed by melting or vaporizing small areas at the surface of the work piece..

EDM process can be compared with the conventional cutting process, except that Use of EDM process has been increasing day by day and also available in most of the machining centers as conventional machines, compelled us to call this process as conventional/traditional process.

Conventional/traditional machines means available every where.

in the case, a suitably shaped tool electrode, with a precision controlled feed movement is employed in the place of the cutting tool, and the cutting energy is provided by means of short duration electrical impulses.

EDM has found ready application in the machining of hard metal and alloys which can not be machined easily by conventional methods. It plays a major role in the machining of tools,dies etc., made of tungsten carbides , stellites or hard steels.

produce desired shapes,size,complicated shapes of hard metals. As this proce=ss Conventional machining is adopted by

But I think the name unconventional is with reference to non-contact material removal process. So how is this justified?

As per my knowledge I have elaborated, Please you may also justify the same that will enhance my knowledge . but this is also called non traditional machining. Due to above reason, EDM replacing conventional machining.

Generally the traditional machining process called conventional have physical contacts between the tool and the work piece. In EDM the electrical spark is used for MRR. It is one of the most extensively used advanced material removal processes. The capability in machining hard material is the main advantage of this system. However, there is no universal criterion regarding machining condition for all parameters combinations.Now EDM AND WIRE CUT EDM have become very widely accepted machining process in industries and accepted as traditional and or conventional.

I agree with Bhuvenesh sir.. Processes that involve physical contact of tool and workpiece during material removal process are called as "conventional" and those which do not have physical contacts are called as "non-conventional."

I think the discussion is described much easier than before. If you want to make an unambiguous assignment, EDM is a processing of electro-technology. In the 1950-1960 years, all the newer processing methods were classified as non-conventional and so it is partially remained until today.

The term "non-conventional" but has no relation to the "non-contact" method, because all combination methods (mechanical-electrical = ECDM) are assigned to the non-conventionalmethod.

Best regards

Hans-Peter

Thank you all for the answers..

I think that conventional processes are when the tool is in contact with the material to be cut, like turning, milling, grinding. EDM for me, is a non conventional process.

Thanks @D. Martinez Krahmer 

My point of view is also same.

I think the last definition is not very clear. for then must all combination method of EDM with mechanical methods are assigned to the conventional. There are also ECDM (Electrical Discharge- Electro Chemical Machining), where the electrical breakdown occurs through solid layers.

Dear Shivraj,

About a decade back I wrote in my book (Advanced Machining Processes by VKJain, Allied Publishers, India) that many of the unconventional machining processes are no more unconventional because they are so commonly used  in medium and large scale industries that the word unconventional is no more relevant / valid. However, it will continue just like the tool material HSS which is no more High speed (steel).

VKJain

 Unconventional machining are earlier known as non-traditional machining processes. Nowadays no more unconventional and non-traditional because they are so commonly used and called Advanced Machining Processes . 

Dear Mr. (Dr.) Bhuvenesh,

I fully agree with your renaming as " Advanced Machining Processes".

VKJain

I think the term non-traditional or Advanced Machining Processes is significantly better than non-conventional. Consider the method Electrical Discharge Machining (EDM), Electro Chemical Machining (ECM), Electro-Magnetic Effect (EME) and Electro-Hydraulic Effect (EHE) and their combination method (also with mechanical removal-processes), then the term is Electrotechnology on most suitable.

HPS

The important thing is the perspective / reference with reference to which some one is using the phrase 'conventional EDM'. If I am talking about the principle of Electric discharge micromachining (EDMM) then I can easily say, "The working principle of EDMM is the same as that of conventional EDM". On the other hand, if I am talking about a hybrid process (Electric discharge grinding - EDG), then I can correctly  say that  the working principle of conventional EDM and EDG are quite different.

The reference point is always important. You are elder to your younger brother but at the same time you are younger also to your elder brother. You are elder as well as younger at the same time when the reference is changing. Thus, EDM is 'advanced' as well as 'conventional' at the same time.

VKJain

Is a very interesting point of these terms, and I can also fully agree with the. But there is also the problem that I come to different amounts of process under this term non-conventional machining with different reference points. As a physicist, one always wants a clear, fixed assignment of concepts. For example, in the electro-erosion there is a group of scientists who describe the pulse time t (on) what is actually derived from circuits. When a pulse at the working gap becomes effective, the transistor is not necessarily t (on), so my understanding is the term t (e), or t (i) is much clearer, because it means te is the time where erosion can occur in the gap.

HPS

Because of its ability for hybridisation with other conventional and non-conventional processes, EDM variants like die sinking, wire cut EDM, electric discharge drilling , electro-discharge milling, electro-discharge grinding, electric discharge coating, electric discharge texturing and electric discharge deposition/welding are in practice. In earlier times, application of EDM was limited for processing conductive materials. However, recent developments have shown that it can be used for conductive, semi-conductive and insulating materials like glass and ceramics , composites.

Moreover, EDM processes have gone through considerable changes in terms of types of dielectric fluids used and modes of dielectric supply. Hydrocarbon oils, water-based solutions, synthetic and mineral oil, and gaseous dielectric fluids have been experimented with wet, powder mixed, dry and near-dry modes of dielectric supply. EDM process has expanded its stems into the manufacture of simple to the most complex geometrical profiles, meso- to micro-manufacturing, processing of low to high melting temperature materials, processing of soft to the hardest materials and generating rough to mirror finished surface accuracies.

for more information on this, you may refer my recent publications available on springer, taylor & francis and Sage.