Yet another Electrode post

[Jammer™]

I have been searching the forum and reading all the post on electrode making. Currently the way we do it is lying about the cutter dia. We burn with an orbital pattern mostly and of course we get a small radius where we should get a sharp corner. After reading up on the negative stock feature, I am wanting some reassurance on this method. If I am cutting a trode with .010 p/s overburn, and I tell MC the true cutter dia, and use -.010 negative stock in my parameters, then when I am setting my tool offsets on the machine, I should come up in my z axis .010. Now when I go to burn in the edm, will I get my sharp corners, or will I still get a small radius? My question I guess is: What is the best way to machine the trode and get a sharp corner on the part in an orbital pattern on the edm machine?

[mold100]

Essentually (sp?) there isnt a big differance in the way the you machine the trode, Although lying isnt the answer.If its a 2d orbit your radius will be the amount of the overburn, if say your burning an inside sharp with .006 per side overburn and a 2d orbit you will actually end up with a .006 radius in the corner.There are only a few machines that can burn 3 axis and get what your looking for,Makino and Sodick are 2 and I believe Mitsubishi.You have the tools you need to do away with the cutter manipulatiopn theroy, I did this daily for a couple of years with smartcam before I seen the light.However there is a rare occasion it may need to be done.My.02

[mold100]

Answer-for best result for a true sharp make trodes with differant o.b., maybe 1 rougher @-.01

[email protected] and one with only .001 to .002 and clear

away what is already finished and use good graphite on the finisher.I am used to making complex surface shapes and have to deal with true inside sharps rarely.

[TREV]

jammer

i agree with mold 100 almost . i cut electrodes every day. we use a 3-d burn on 99.9% of all are trodes so cutting to negative stock in the mill makes for correct geometry in burner. the only thing i differ on is that over burn and under size are two completly different things. example say i cut my trode to -.01/ side this alows me to go in with a hotter setting and alows the edm a chance to orbit as i decrease power to a finer setting. so when i get to the last setting my actual overburn (spark gap) may only be .001/side.if you choose to lie about your cutter say .01/side you will have to know what your final over burn will be in edm. lets say it will be .001/side. you will have to then offset your geometry on all angles and radius that amount or you will not get true form. hope that all makes sense. for what its worth if your edm is cappable of 3-d burning negative stock is the way to go (less chance for error)

hth

trevor

[mold100]

Trev thats true with 3d but not 2d orbiting.

there is no D like 3D

[Jammer™]

Thanks alot guys. That is exactly what I wanted to hear. I too have cut trodes for many years, and have always lied to the cutter. We can burn 3d (mitsubishi edm), So now I will change my ways and start doing it with negative stock.

[Jammer™]

One more thing guys, If I cut my trodes with negative stock, won't that affect my flat z depths? Do I raise my tool cal up the amount of my overburn? Or do I compensate for that at the sinker tank? Thanks

[mold100]

No compensation needed.Dont let it confuse you.

[Jammer™]

*brainfart* I got it now!!! Thanks.