Electrode Mfg. Poll

[Fred @ Slate Industries]

How do you Build / Model your electrodes ?

[kickworm]

with spark gap built in the model

[mchin-pilot]

No No ,

 

Electrode is same size shape as is extracted from cavities. You overmachine the electrodes ( Rougher , Medium, Finisher ) by the respective Spark Gaps

 

Simple!!

[JBowman]

The problem I have using negative stock is you’re stuck with 3 axis orbit. We prefer 2 axis orbit to maintain sharp corners and only use one trode design to rough and finish. Currently we have to offset or draw the trode from scratch to get a 2 axis orbit. The only program I found that does 2 axis orbit is Cimatron.

[Mjölnir]

2 axis orbit is easily achieved in Mastercam by cheating tool diameters. Isn't ideal for all situations but gets the jobs none the less.

[JBowman]

quote:

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2 axis orbit is easily achieved in Mastercam by cheating tool diameters.

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So how do you cheat on a ball mill doing a surface?

[Mjölnir]

quote:

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So how do you cheat on a ball mill doing a surface?

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Don't use ball mills when surfacing electrodes for 2D orbit. I use bull nose tools almost exclusively.

 

Both Powermill and Cimatron indeed do this far better than Mastercam ever will. But it's not at all impossible with Mastercam, IF you use your noodle.

[Rick46]

what kind of tooling strategies are most of you using.. currently going down some rocky roads with our edm dept with the trodes we machine..I try and use most ball nose mills for all trode machining unless geometry prohibits it.. the edm guy complains that the radius left at the base of wall on elctrode is gonna burn into steel where its not supposed to or not.. complains of no flat areas to touch his trodes off on if the trode dosent have any.. just looking for different approaches and methods in maching electrodes.. thanks...

[Mjölnir]

If there aren't any flat areas to pick depths up from on the shape to be burned, establish a known depth on the shank of the electrode past the burn and the EDM guy will pick up from that. If there isn't enough of a shank to do this, than an extra "pick up electrode" should be made for that particular set.

 

I avoid using ball end mills for finishing unless either the shape dictates their use or if cycle time would be ridiculously long using bull nose tools. Ball tools do last longer for roughing, up to 3/8 dia at which size PCD tipped indexable bull nose tooling is readily available.

 

For the radius at the base of a wall, you must, without fail, extend the electrode past the wall or corners will get rolled slightly exactly as your EDM guy says. This particular thing is elementary. It should have been one of the first things you were taught about electrode making.

 

Hope that helps.

[JBowman]

quote:

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Don't use ball mills when surfacing electrodes for 2D orbit

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Allot of our electrode detail dictates using very small ball mills. I’m hoping Mastercam will add the 2d offset feature in the future.

[Jack Neelands™]

negative stock for 3D works for me ...I dont do any Orbiting

[Henry]

By cheating tool diameter you can get long if you only use 3 axis milling .With 5 axis you can't but have to use negative stock.We try to avoid ballmills as much as possible.They have zero cutting speed and two cutting edges at center only,you know.And that center wears out very quickly.Every trode has box at the bottom for center verification and for length measuring.Also with two chamfers so EDM guy doesn't machine trode rotated wrong position.

[Jack Neelands™]

I usually try to lock in an axis so that my tool moves up and down the radius of the ball when doing parallel surfaces.