Ram EDM'ing pure tungsten
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    Default Ram EDM'ing pure tungsten

    Greetings,

    Does anyone have suggestions for cutting pure tungsten (99.95%) with copper electrodes on a 1986 Hansvedt 201? I've been able to do it with negative polarity on the electrode, but it's just unbelievably slow and the electrode wear is atrocious. The dielectric is new Ionoplus. I started with the recommended settings for tungsten carbide, and then did a lot of experimenting. I'm trying to cut some holes using tubular electrodes and flushing through the tube. Anyone ever done this?

    It seems most of the time people end up cutting heavy tungsten alloys, copper tungsten, radiation shielding tungsten alloys, etc., which have other elements in it that make it much more manageable. This pure stuff is unbelievably tough (can't cut it with carbide, for example).

    Thanks!

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    Your kinda behind the eight ball here...
    You have to think of melting temp.
    Your tungsten workpiece melts at a very high temp.
    The only way you are going to get non-atrocious electrode wear is to use an electrode with similar or better melting temp.
    I would recommend copper tungsten.
    The copper for lending ions and getting the spark going, and the tungsten for melting temp.
    Try and keep your spark gap as large as possible in order to keep the heat as far as possible from your electrode.
    Unfortunately, that means more material removed...which slows the process again.

    Are you trying to just put a hole in or are you trying to burn in a shape?


    Jay Crumb
    Advanced EDM, LLC
    [email protected]

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    Jay, thanks for the response. I'm just trying to put through holes in for now, although I will also need to do some other geometries soon.

    I actually found conditions that worked for me. I needed to set the pulse width to the absolute minimum, turn the current all the way up, and decrease the off time as much as possible. That allowed the material to be cut at a reasonable rate, although as you pointed out, the wear on the copper electrode was "atrocious" (probably 150%). I also had very good flushing. When I asked the question earlier, I was at the opposite end of the settings and trying to use very long pulse widths. I think I was mostly plating the tungsten back onto the copper, or possibly creating large chunks of tungsten that would short out and cause the servo to retract to prevent arcing. (I found an excerpt online from the book by Bud Guitrau that gave me the clue as to what I needed to do.)

    I'm new to this process, and I'm not trying to hold super-tight tolerances for dies, etc. (at least right now). I will also obtain some copper tungsten and try it, although for through holes the copper seems to work OK. It's a lot easier than drilling it conventionally, that's for certain.

    Thanks!

  4. #4
    Johnny Larue Guest

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    Quote Originally Posted by stevens48 View Post
    Greetings,

    Does anyone have suggestions for cutting pure tungsten (99.95%) with copper electrodes on a 1986 Hansvedt 201? I've been able to do it with negative polarity on the electrode, but it's just unbelievably slow and the electrode wear is atrocious. The dielectric is new Ionoplus. I started with the recommended settings for tungsten carbide, and then did a lot of experimenting. I'm trying to cut some holes using tubular electrodes and flushing through the tube. Anyone ever done this?

    It seems most of the time people end up cutting heavy tungsten alloys, copper tungsten, radiation shielding tungsten alloys, etc., which have other elements in it that make it much more manageable. This pure stuff is unbelievably tough (can't cut it with carbide, for example).

    Thanks!
    yes...I use COPPER TUNGSTEN rods or bars or sheets and wire EDM shape into them....or TUNGSTEN CARBIDE...I have also used BRASS....electrode wear is a lot but if you turn down the capacitance or CAP...you know the setting for the power of the spark....adjust the GAP so that the needles or what ever gauges you have are both clicking together in unison and tiny bumps as opposed to it jumping lots back and forth...or the LED LIGHT BAR GAUGE...same thing....listen for bacon frying if theres sound from it.....hard frying is too much capacitance and a lot of wear....the copper tungsten alloy might be the one for this job IMO....but BRASS is a close second and worth a try as the wire edm uses brass to cut tungsten...use some brass wire edm settings for brass electrodes if machine similar should have similar capacitors and whatnot and settings....good luck....should work....the copper tungsten will last longer

  5. #5
    Johnny Larue Guest

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    if ya doing it like KUMAR just becareful and make sure OSHA not around....LMAO


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    OMG!!!! Probably using Kerosene as a dielectric to boot...

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    What settings would you start with on an Eltee Pulsitron? What capacitor settings also. I have brass and graphite as electrode options.


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