Sub half thou single pass burns

Anyone else doing this? I see a lot of guys running 2,3,4+ passes to get under .0005 on parts. I don't know how stable other machines are but even with our 2006 mits fa10 I can hit well under that in one pass. No special offsets, I have the wire with overburn as a tool in mastercam, that's it. Recently burned some blocks that was drawn and programmed for 1.000, part measured 1.00000 on the mit digi mic all over, square and parallel in 2.000 thick o1.

I wish I had a pic.

Here's a piece I programmed to leave .0005 so I could dust them with a grinder. They are feed plates for injection molds. Cut from a .750 x 2.00 1018 bar.

Hi plastikdreams:
I have found that my problem is more one of losing geometry details than hitting a particular size if I try to make a part of any complexity with a single pass cut.

I use my machine quite a bit as a glorified electric bandsaw to cut tubing and the like to close length tolerances, and this can be done very consistently using a single pass, so long as enough waste stock exists at both ends of the stock to make a proper kerf...if ether side has insufficient stock, the part will end up too long because of wire deflection from the asymmetric flushing pressure.

But for cutting of profiles into a plate, typically I lose geometric fidelity in two places if I try to do it with a single pass.
First is the corners...even with corner control turned on, the corners will be a twitch washed out.
The second is the flatness of the surfaces from top to bottom.
My machine is not great in that regard, and the only things I can try to use to influence the flatness is the cutting parameters.
I've found them to be hit or miss, and since I really don't run production on the machine, it's cheaper for me to just run the skims than to fuck around with setup parts trying to dial in the parameters.
Better machines have better tech for this ... I know Makino offers something called "Belly Wizard" that mitigates this effect and is reputed to be very good.

So for the stuff I do on my medium grade machine, I've not had good success dodging the skims, and it hasn't been worth it to me to get better at it.

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining

I hear ya. It took a lot of trial and error at first with epacks, flushing, and overburn. I find using pm does it well but on thin walls it can speed up too much and leave marks or drift. Kinda gotta know when to turn it off.

Like Marcus said, the details might get washed out with a single pass only strategy.
BUT!!!
Production parts rarely have that much concern for details as to worry about it!

For me, if the part is a production run AND it is no less than +/-.0005 tolerance, I don't even think about skimming!

SeymourDumore said:

Like Marcus said, the details might get washed out with a single pass only strategy.
BUT!!!
Production parts rarely have that much concern for details as to worry about it!

For me, if the part is a production run AND it is no less than +/-.0005 tolerance, I don't even think about skimming!

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Yeah when I ran production it's was balls to the wall...which still isn't very fast with edm lol.

I remember one time I was making 2 arms from 1.000 thick 6061 for a project I designed and built...I cut them on one of the mv2400 machines with 12 wire and was getting consistent. 75 ipm...fastest I've ever seen a wire go lol.

My single cut stuff can sometimes be +/- 0.01mm but I wound count on it for that size, our Sodick can cut -0.00,+0.005mm in steel on the quickest three cut all day long, I don’t size anything in as I don’t require sub 5 micron tolerances.

Anything more than 2 skims is electropolishing.

pr0xify said:

Anything more than 2 skims is electropolishing.

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Pretty much. I only ever do more than 1 or 2 skims unless I'm looking for a good finish.