Electrical Discharge Machine – Spark Erroder…

[StephParticipant @steph]

I am looking for a good set of plans to convert or adapt a mill/drill to cnc EDM, as need to produce a number items in tool steel.

Is there a good source for this information, as I do not wish to invent the wheel.

Regards

Steph

[StephParticipant @steph]

Comments and advise requested.

[CirclipParticipant @circlip]

 Try MEW issues 57 – 60, with updates iss. 64 and 68

 

     Regards  Ian.

[StephParticipant @steph]

Many thanks Ian, does anyone have a pdf copy of these articles in these issues, as I do not have these in my collection.

I am willing to pay costs.

Regards

Steph

[Ian S CParticipant @iansc]

Hi Steph,I found an artical, Model Engineer vol142 no.3542 p. 750 (Aug 1975),this is part 2,part 1 is on p.692,I thought I had both parts.If you can get a copy it should give you some ideas at least.

[Ian S CParticipant @iansc]

Hi Steph,I found an artical, Model Engineer vol142 no.3542 p. 750 (Aug 1975),this is part 2,part 1 is on p.692,I thought I had both parts.If you can get a copy it should give you some ideas at least.
Ian S C

[Mark FraserParticipant @markfraser24249]

Be very cautious with this circuit – I believe that it connects directly to 

mains…. /mark in Canada

[Ian S CParticipant @iansc]

Hi Mark,no the cicuit is powered by a double wound transformer,ie isolated from mains.One secondry is11.3v for the motor control,the other is 250v to the head,but you proberbly don’t want to put your finger in there anyway.

[Ian S CParticipant @iansc]

Hi Mark,the machine is powered though a transformer(x radio),sec(1) 11.3v for the motor control,sec(2)250v for the head,you proberbly don’t want to get your finger in there!…./Ian S C new zealand.

[Gerald WeareParticipant @geraldweare85524]

Hi,

If you need it I have a PDF of the two articles mentioned, from JUly/Aug 1976 by Roy Amsbury.  I actually got it off the web at http://www.metalwebnews.com/manuals/spark–erosion.pdf but I can email you a copy if you’d rather.  (Don’t know why that went green)

 

Roy published another article in 1980 with some improvements and changes for out of date electronic parts.  This is also included in that same PDF.  You might have trouble finding the stepper and stepper driver chip, but there is plenty of info on the web about building such things – much better these days than 1980.  Personally, I think I would build it as an attachment for my cnc mill and program the vertical motion, thus eliminating the stepper motor and drive electronics.  You could also program the X and Y, which would greatly expand the scope of Roy’s machine. The drive really isn’t much more than a slow power feed, as you can control the speed but not position.  If you had a slow enough Z axis feed on your manual mill or drill, you wouldn’t need the stepper motor and electronics even for non-CNC.  Of course, you still need the spark generator.

 

As far as safety, it looks OK to me, as far as 250V to a sharp-pointed electrode can be safe!  I would be pretty happy to trust Roy’s design anyway, seeing as he was a well-respected electronics engineer at Rolls-Royce Derby for many years.  Having personally seen both his electronics work and his live steam work, I can assure you he was both a genius and a true craftsman.

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