Electric Discharge Machines (EDM) affect on material 1

[cpp01]

Hello all!
Just curious as to if anyone is aware of the affect of EDM's on materials, particularly steel. I heard that it interferes with the grain boundaries. Is this true?! I receive work from two suppliers, identical material, but one produces it under mass production conditions and the other in a specialist unit. The properties, following a heat treatment at my plant are varying and sometimes they are identical but at other times the mass produced ones are of a poorer quality. I believe they may be rushed during cutting, does this result in burning similar to a standard saw? I'm not used to this equipment so not sure of whats going on! Thank yoy for your time!
CP

 

[NickE]

have to run... but I will tell you that the speed at wich an EDM machine is run is related to the finish it produces. Or the other way around. EDM also produces an HAZ albiet a very small one. we definately can see a change in flexing fatigue of edm reed valves vs stamped vs chemically etched....

hth
nick

 

[metengr]

We have had new steam turbine blade roots cut by the EDM process. I have never seen a quality problem regarding surface finish or variable blade root tolerances during installation of the new turbine blades in the field. However, like any process, if it is not done correctly, problems can develop. Here is an interesting paper on the subject.

http://www.td.co.za/edm.pdf