Author Topic: Sinker EDM question  (Read 1314 times)

Offline Alphawolf45

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Sinker EDM question
« on: January 18, 2019, 01:15:29 PM »
 I finally got my sinker edm running again. I had only operated it once last year when I first got it so I don't really know how to use it or exactly what I should expect from it. It's primary malfunctions is just the idiot that is trying to run it without consulting the operators manual...

    It is capable of 50 amps output but I am running it at 10 amps so that I don't pop the fuse , my 5hp rotary phase converter cant supply enough juice to it to run at 50 amps - I may get 20 amps if I push it......Irregardless . At 10 amps using a 1/2" square graphite electrode I am only burning .001 depth per minute in a steel workpiece.. Does that sound right.?? That my friends is slower than slow..


  Also, an 85 yr old still working tool and diemaker friend of mine talks about arcing going on that damages the workpiece and the electrode... What is that and how do you recognize it? I can call him but he is real hard of hearing, doesn't hear his own phone ringing unless he is near it. Photo shows my EDM today with most of it's covers pulled.. I like it a lot but I am afraid the beastie don't much like me.
I am not actually retired ,I merely find myself disabled by an intolerance for productive activity.

Offline seadog

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Re: Sinker EDM question
« Reply #1 on: January 18, 2019, 01:31:47 PM »
awemawson is your man. He has a working EDM. I'm sure he'll be along soon.

Offline Alphawolf45

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Re: Sinker EDM question
« Reply #2 on: January 18, 2019, 01:49:25 PM »
 Yeah ,before I had chemo therapy screw with my head I was maybe  half as bright as Awemawson.. Now I need an extra heaping of  help.. :doh:
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Offline kayzed1

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Re: Sinker EDM question
« Reply #3 on: January 18, 2019, 02:47:19 PM »
Yeah ,before I had chemo therapy screw with my head I was maybe  half as bright as Awemawson.. Now I need an extra heaping of  help.. :doh:

I thought it was only me..tis a bit of a bugger when you think you no what to do with a project only to find you need help, the help you used to give others before the
big C..  Keep on keeping on thou.
Lyn.

Offline Alphawolf45

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Re: Sinker EDM question
« Reply #4 on: January 18, 2019, 04:16:32 PM »
  Shoot man, I used to sit in my backyard watching my dogs  and write out G-code for my oldest cnc mill and I'd compute the trigonometry in my head. I can barely do anything anymore. Doc says it will be 6 months until my brain gets back to normal.. Cancer is bad , Chemo is the killer of the bad cells and also those we need to figure stuff out...I dunno, my Mother died from my same cancer 1 month before I got my diagnosis. Dying is in the future of all of us,, Let me think clearly before I take the dirt nap.Dull brain is pretty awful..
I am not actually retired ,I merely find myself disabled by an intolerance for productive activity.

Offline Alphawolf45

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Re: Sinker EDM question
« Reply #5 on: January 18, 2019, 05:01:13 PM »
 10 years ago I applied for a job at a big company.The job was for operating a cnc mill.....You know what kind of job that is-- basicly loading and unloading and loading and unloading parts into the machine.. Okay I had to take a test..I arrived several minutes after the test had begun.. I noticed that I was the only person in the room without a calculator. However I finished first...Test results showed that I had finished highest that was graded or considered...I didn't get the job as somebody with darker skin and a lower grade was give the position. Not that I care. Just interesting.
I am not actually retired ,I merely find myself disabled by an intolerance for productive activity.

Offline awemawson

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Re: Sinker EDM question
« Reply #6 on: January 18, 2019, 05:18:51 PM »
Somewhere on the forum is a thread where I was sinking a 1/2" square using a copper electrode and I seem to remember that Pete-W asked how fast it went - can't for the life of me find the thread but it's here somewhere  :med:

 . . or it may have been the thread about making a big grub screw  :scratch:

As for arcing - that's bad. The electrolyte combined with the electronics should be totally preventing arcing. The discharge should happen in the last few microns of approach and the electronics cut off as soon as it happens

Oelheld have (or certainly had) a good downloadable EDM handbook on their site in the IONO-PLUS area.
Andrew Mawson
East Sussex

Offline John Swift

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Re: Sinker EDM question
« Reply #7 on: January 18, 2019, 05:35:02 PM »
quote

"I didn't get the job as somebody with darker skin and a lower grade was give the position. Not that I care. Just interesting".

many bosses are second rate   but they know enough not to don't take on any one thats  too bright ,
threaten their position and take their job

                       John

Offline Alphawolf45

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Re: Sinker EDM question
« Reply #8 on: January 18, 2019, 06:28:00 PM »
 You make no sesnec.
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Offline awemawson

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Re: Sinker EDM question
« Reply #9 on: January 19, 2019, 04:09:20 AM »
What John is saying (that makes perfect sense) is rather akin to the Industrialist who told his secretary to search throughout his empire to find the absolutely BEST person to take over from him - then FIRE him  :clap:
Andrew Mawson
East Sussex

Offline Alphawolf45

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Re: Sinker EDM question
« Reply #10 on: January 19, 2019, 06:52:57 AM »
 I am not too bright as I apparently cant spell.

    Thanks guys You have answered my question good'nuff. I will presume that .001 per minute at 10 amps is within the range that is considered normal...And terrible slow :palm:

  As for the job I applied for and didn't get. I didn't want anything except the chance to play with a newer cnc mill Than I have.. Consider that we have to buy our own machines and repair them and continually feed them new endmills and drills and inserts.. It would be nice for a while to run somebody elses machine and not be responsible for the costs of running it.
 
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Offline tom osselton

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Re: Sinker EDM question
« Reply #11 on: January 19, 2019, 01:56:36 PM »
Had to buy your own machines! WTF!

Offline Alphawolf45

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Re: Sinker EDM question
« Reply #12 on: January 19, 2019, 02:04:40 PM »
 Ohh my I laugh so much, Tom you are a comedium.  :mmr: :mmr:
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Offline Alphawolf45

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Re: Sinker EDM question
« Reply #13 on: March 01, 2019, 08:06:10 AM »
I bought a 20 hp rotary phase converter to power my EDM and am wiring it up today because I need to use the EDM this weekend. .I am sorta excited because the EDM was brutal to my 5 hp rot. phase converter.
      I do have a good quantity of Graphite for electrodes but copper wears more slowly and doesn't coat the whole room with graphite dust when machined. But my question is this. I have a lot of bronze and brass and only a closely guarded little stash of copper. What would happen if I tried using a bronze or brass electrode? I will guess that brass would work fine aside from some roughness where the zinc would burn away quick ? Would the zinc contaminate my dielectric fluid?
I am not actually retired ,I merely find myself disabled by an intolerance for productive activity.

Offline awemawson

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Re: Sinker EDM question
« Reply #14 on: March 01, 2019, 10:04:50 AM »
I have used brass successfully when desperate, but the zinc content contaminates the dielectric and also blocks the filters. Wear is an issue with brass but if only doing  a single burn such as removing a small tap it doesn't matter much.

Like you I have a fair amount of graphite (Mainly Poco) but I try to avoid it due to the mess it makes. When I got my machine back in the dim and distant past, it was choked with graphite dust, both in the electrolyte tank and in the electronics cabinet, and it was a real pain cleaning it up (and also me afterwards !) so I try and avoid using it if possible.
Andrew Mawson
East Sussex

Offline Alphawolf45

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Re: Sinker EDM question
« Reply #15 on: March 01, 2019, 10:35:34 AM »
Thanks Awemawson
  There is nothing better than hearing from a Man that has done it.
    I don't want to contaminate my 450 liters of dielectric.. So I'll use graphite for this one as it seems unavoidable... I made a few graphite electrodes for a machinist friend years ago and I am still finding traces of that dust - I hate graphite and sawdust around my metalsworking machinery :bang:
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Offline AdeV

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Re: Sinker EDM question
« Reply #16 on: March 01, 2019, 05:29:51 PM »
I hate graphite and sawdust around my metalsworking machinery :bang:

At least graphite lubricates "as is": With sawdust, you have to soak it in oil before it has decent lubricating properties  :lol: Of course... the disadvantage of graphite is it's conductive  :zap:, so don't try lubricating electronics with it!  :scratch:
Cheers!
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Offline awemawson

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Re: Sinker EDM question
« Reply #17 on: March 02, 2019, 02:36:06 AM »
If you are turning graphite on the lathe, a lot of the mess can be caught at source by holding the nozzle of the workshop vacuum cleaner close to the tip of the lathe tool

Andrew Mawson
East Sussex

Offline Alphawolf45

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Re: Sinker EDM question
« Reply #18 on: March 02, 2019, 09:01:12 AM »
ADEV I had not considered the lubricity of the graphite ,so guess aside from the mess it shouldn't hurt the machine's ways. I appreciate that comment.

awemawson I have tried the Shop Vac hose . That does help but would need a way to attach the hose to the machine to free up both hands ..And too , during hot weather I have the air-conditioner and sometimes also a fan circulating air in the small room - so I turn those off while machining graphite.. Then I am miserable . I sweat and the graphite dust sticks to me as well.. I think there is no way to make the machining of graphite neat and pleasant... The only good thing that I can say about it is that graphite machines beautifully- the good grades anyway- I haven't used the cheap soft brands.
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Offline awemawson

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Re: Sinker EDM question
« Reply #19 on: March 02, 2019, 09:10:40 AM »
Bent and twisted coat hanger holds vac hose quite adequately  :clap:
Andrew Mawson
East Sussex

Offline Alphawolf45

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Re: Sinker EDM question
« Reply #20 on: March 02, 2019, 09:23:29 AM »
 The funny thing is awemawson , there isn't a metal coathanger anywhere in this house as Wife has changed to all plastic ...But I understand what you are saying.. A handy fellow with a shop full of tools could rig up something nice. And I will add that project to my list. :beer:
I am not actually retired ,I merely find myself disabled by an intolerance for productive activity.