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Liger Zero
04-20-2010, 01:32 PM
Went to look at an EDM-contraption today. It was under power, they showed me how it all works. More or less it uses a graphite electrode, a jet of fluid and a bunch of control settings to burn holes in small pieces of work.

Guy claims it can be used to do EDM-milling too provided you don't get too aggressive with it.

I am a totally blank page when it comes to EDM. I know what it is, I know kinda how it works, but when I worked in machine-shops it was considered black-art arcane-magic stuff and no one ever bothered to explain it other than "GET AWAY FROM THAT!" :D


Anyone have any experience with these graphite electrode hole-poppers? CAN they be used to do milling or is he just trying to sell me a fancy electric drill?


Might be worth the price to acquire and learn if that's the case.

Weston Bye
04-20-2010, 01:42 PM
Village Press sells a book on building your own EDM. I built one. It works, but I haven't had much opportunity to use it.

Burned a "9" shaped hole in a detail, made the electrode out of brass.

Liger Zero
04-20-2010, 01:50 PM
Well I am gradually ramping up my injection molding concern... not at the point where I can build world-class molds (that'll never happen) but I have a couple ideas in mind.

I was told that you can shape the electrode, and burn an exact image into a chunk of steel. If that's the case, I could make "mini-figures" for the Role Playing Game market. THEY don't have to hold a three digit tolerance, they just have to look nice. ;)

I guess what I need is a good source of information on what this process can do for me. Even if this machine gets away there will be others.

Paul Alciatore
04-20-2010, 01:54 PM
I saw one in a shop, but it wasn't in action. It did look neat.

I am saving some big capacitors for making one but I'm far too busy with other things now.

If you do make one, please share pictures.

Liger Zero
04-20-2010, 02:01 PM
This is a fully self contained unit with a name badge and everything. Charmian I think? I forgot.

It's mounted on an old BP body, they took the mill-head off and mounted the EDM contraption on here.

Mcruff
04-20-2010, 02:30 PM
I have run ram type EDM's alot, in the 1000's of hours. If this machine does not have the ability to pulse you will have problems. Hole poppers lack a lot of the fine controls that make EDM work well. They are designed for simple round trodes, usually using EDM drills for thru flushing. If you get a hold of a drawing or photo of the power supply showing the controls I can tell you for sure if it will work for small trodes.
It will need to have a amp control of some kind (15 amp minimum power output), on time and off time controls, gap control and an electric or hydraulic pulsing head with a speed control and a +/- polarity switch. It will need some sort of flushing system , water or dielectric fluid. There may be other controls but these are imperative.

Liger Zero
04-20-2010, 02:40 PM
Going on memory... The power supply is 200 amp he kept mentioning that because apparently it matters... it had a CRTfor on-off time (he explained how that works, sort of), the head moves up and down via a servo, controlled by the PLC, and it does have a polarity switch.

As for the fluid system... two hoses feed two flexible jets that gush fluid at the electrode gap. The fluid washes down off the fixture-table and is collected by two hoses that drain into the fluid unit.

The entire fixture-table is mounted on the BP table and takes up quite a bit of room.... It does have a plastic enclosure, he said that's used if you need to submerge the work for "certain operations."

Everything is controlled by that PLC/CRT thing except for the polarity, which is a bit selector switch.


Does this help?

MaxHeadRoom
04-20-2010, 03:08 PM
It sounds like you have a form of die sinking EDM, at first I thought it may be a Tap Disintegrator, the technique is similar but the method is quite a bit different between the two.
EDM is by high voltage DC and spark erosion by constantly maintaining a small arc gap between work and electrode with typically some kind of servo action that measures the voltage rise & collapse.
The Tap Disintegrator looks the same but uses very low voltage, high current AC and the electrode is crudely advanced into the work with a simple 60hz vibrating head.
M.

Ron Davy
04-20-2010, 03:28 PM
I think its called a elocks for burning out taps

MaxHeadRoom
04-20-2010, 04:23 PM
I think its called a elocks for burning out taps

elocks ? If you mean Elox they build Die sinker EDM's
A principle maker of Tap disintegrators is Electro-Arc.
M.

Bguns
04-20-2010, 04:34 PM
They are still in business, US distributor here: http://www.charmillesus.com/products/edm/index.cfm

wierdscience
04-20-2010, 07:48 PM
elocks ? If you mean Elox they build Die sinker EDM's
A principle maker of Tap disintegrators is Electro-Arc.
M.

Elox also built tap burners,I have one.

wierdscience
04-20-2010, 07:53 PM
Going on memory... The power supply is 200 amp he kept mentioning that because apparently it matters... it had a CRTfor on-off time (he explained how that works, sort of), the head moves up and down via a servo, controlled by the PLC, and it does have a polarity switch.

As for the fluid system... two hoses feed two flexible jets that gush fluid at the electrode gap. The fluid washes down off the fixture-table and is collected by two hoses that drain into the fluid unit.

The entire fixture-table is mounted on the BP table and takes up quite a bit of room.... It does have a plastic enclosure, he said that's used if you need to submerge the work for "certain operations."

Everything is controlled by that PLC/CRT thing except for the polarity, which is a bit selector switch.


Does this help?

It's more of a tap burner,maybe odd shaped hole machine more than a die sinker.I had a similar unit made by Excello of milling machine fame.

It was basically a knee mill frame with an EDM head in place of the mill head.Mine came with a seperate cabinet on wheels for the electronics.All analog controls,heavy DC current.It was still just a tap burner,but the knee mill table was in great shape,that's why I bought it to make it back into a mill.Ended up selling the control in pieces and scrapping the knee mill base in parts.

Bottom line it ain't a real EDM and it ain't worth much.

MaxHeadRoom
04-20-2010, 07:54 PM
Elox also built tap burners,I have one.

I wasn't aware of their disintegrators, but I believe they are principally know for their Die sinkers, at least this is the models I have come across so far.
M.

wierdscience
04-20-2010, 07:59 PM
I wasn't aware of their disintegrators, but I believe they are principally know for their Die sinkers, at least this is the models I have come across so far.
M.

Yes,they did make some nice sinkers,AFAIK they made both the tap burners and die sinkers and where later bought out/sold to/merged with Charmilles which is still very much alive.

I had a chance a year ago to buy a Charmilles sinker,like new with pallets of filters,boxes of carbon and a several sets of 3R tooling.Could have got it for less than $1,000,but I didn't need another hobby.

Mcruff
04-20-2010, 08:42 PM
A 200 amp power supply would not be on a tap disintegrator or a hole popper, 30 amp maybe but a 200 amp EDM is a hell of a machine and capable of 150lb electrodes or larger, we had a 100 amp Elox back in the early 90's at a shop I worked at that was huge. Most sinkers are in the range of 25 to 50 amps. A picture would help here, there were hole poppers and tap busters designed specifically for the back end of a Bridgeport where the shaper went that do sound like what you describe minus the 200 amp output. I ahve run a loat of different types of sinkers over the years and I have never seen one that goes on Bridgport. Eltee pulsitron made one that was built on a Moore jig grinding frame and it was probably one of the best ever built, precision within a .0001 when most others were lucky to build one that was accurate to a .001.

MaxHeadRoom
04-20-2010, 09:17 PM
The ElectroArc that I have repaired/rebuilt in the past, have a huge transformer, I am not sure of the Kva, but the voltage is only around 9 -12vac, they rely on a large arc current to blast the metal away, it could be easily rated at 100amps or more.
EDM is high voltage DC at a much lower current.
A lot less harsh arc to obtain the fine finish you need with a Die sinker.
I just looked up my records and the Electroarc go up to 20Kva!
M.

projectman
04-20-2010, 10:19 PM
It could be a ERM or a XERMAC we were the only ones making bp conversions they are a plunge edm machine I built them for 17 years at erm/xermac we closed 2003 we built manual and cnc from 30 amp to 400 amp .

duckman
04-20-2010, 10:58 PM
Ran my share of Eloxes in the late 60s, from little ones up to 400 amps that was some scary beast when really cranked up it could burn 16 cubic inches per minute the little craters were about 3/32" in dia. and is sounded like a giant fry cooker. We never had just 1 carbon electrode to do a job they wear away, and the critical thing was getting the flushing fluid to the bottom of the burn, if you didn't you would get a little tit sticking out of the electrode which would then burn a hole in the cavity. What surprised me the most when I started was gluing the carbon to steel shanks, we used Eastman 910 instant glue and it has conductivity. the only down side then was the smell of the dielectric oil we used.

outback
04-21-2010, 05:26 PM
Home built sinker:

http://img.photobucket.com/albums/v30/jglass/Automation%20Projects/sinkingEDM.jpg

Keyway made with EDM
http://img.photobucket.com/albums/v30/jglass/EDMkeyway.jpg

See it run:
http://smg.photobucket.com/albums/v30/jglass/?action=view&current=EDMworking.flv

Outback

MaxHeadRoom
04-21-2010, 05:55 PM
Home built sinker:



Any particular design you based it on?
Or you own?
M.

Liger Zero
04-21-2010, 09:21 PM
Ok, further investigation it's a "custom" job. The head is off of a charmilles machine, mounted on a BP... it has a 200 watt power supply. The head has all it's functionality, but the table is a manual BP mill.

They built it for a specialized production job, that involved burning specialized holes, then they used it as a hole-popper, then they decided to just get rid of it because it's a kludge.

I'm told 200 watts is a bit powerful. Yes? No? Get a god-damn text book and stop bothering you?

wierdscience
04-21-2010, 11:00 PM
Ok, further investigation it's a "custom" job. The head is off of a charmilles machine, mounted on a BP... it has a 200 watt power supply. The head has all it's functionality, but the table is a manual BP mill.

They built it for a specialized production job, that involved burning specialized holes, then they used it as a hole-popper, then they decided to just get rid of it because it's a kludge.

I'm told 200 watts is a bit powerful. Yes? No? Get a god-damn text book and stop bothering you?

Is 200watts a typo or the rating?If it's 200amps,then ya,it's fairly well endowed.

200 watts,then it's a weak hairdryer.

How much do they want for it?

Liger Zero
04-21-2010, 11:57 PM
Amps. Sorry The Wife was sitting next to me, she causes typos just by being in close proximity. :D

And it is cheap enough that I'm going to cut them a check tomorrow for it. I have enough power to make it go, and my friend Dawn has agreed to teach me how not to blow myself up (and my cat too!) with it.

Figure what the hell, might as well teach myself a new trick. If it can actually "burn" shapes then... well I have some ideas we'll see. :cool: Otherwise I have a bitching "electric drill" to scare the neighbors with. :D:D

joeby
04-22-2010, 07:07 PM
FWIW, Elox merged with Agie, two of the newer Agie sinkers I ran had Elox voltmeters and ammeters on them. The Agie Techs that I had spoken with said the Elox employees were moved into Agie facilities creating some interesting situations.

Georg Fischer now owns Agie, Charmilles, Mikron, (Boston Digital was bought by Georg Fisher and merged with Mikron) and 3R (I think).

Kevin

Liger Zero
04-22-2010, 07:34 PM
FWIW, Elox merged with Agie, two of the newer Agie sinkers I ran had Elox voltmeters and ammeters on them. The Agie Techs that I had spoken with said the Elox employees were moved into Agie facilities creating some interesting situations.

Georg Fischer now owns Agie, Charmilles, Mikron, (Boston Digital was bought by Georg Fisher and merged with Mikron) and 3R (I think).

Kevin

How good are they at supplying repair parts for old machines? I understand this is a bastardized kludge of a machine but if I need a framastat relay for my jehovahnator clutch will they be able to help me? Or are we talking "You want a WHAT? for a WHAT?! BUAHAHAHAHAHA!" kind of service?

wierdscience
04-22-2010, 08:03 PM
Amps. Sorry The Wife was sitting next to me, she causes typos just by being in close proximity. :D

And it is cheap enough that I'm going to cut them a check tomorrow for it. I have enough power to make it go, and my friend Dawn has agreed to teach me how not to blow myself up (and my cat too!) with it.

Figure what the hell, might as well teach myself a new trick. If it can actually "burn" shapes then... well I have some ideas we'll see. :cool: Otherwise I have a bitching "electric drill" to scare the neighbors with. :D:D

Cool,let me know when your up and running,might have some oodball shaped holes I need done.

Liger Zero
04-22-2010, 08:29 PM
Will do. May 3rd I leave for about 16 weeks to join the world of the Naval Reserve... When I regain my Civilian Who Pretends To Be A Sailor status I intend to learn EDM with the intention of using it to construct injection molds.

Black_Moons
04-22-2010, 09:11 PM
Sounds like a pertty cool rig, and at the very least you should have an awsome tool to get broke drills and taps out :)

Herm Williams
04-22-2010, 10:43 PM
I have burned square holes in broken bolts and studs that made it easer to remove. My elox and elextroarc have 220v 25amp breakers. The elox has a connection for arc welding but I have not used it.
re

joeby
04-23-2010, 11:08 PM
I'm not sure how Charmilles support is, but I never had any problems with Agie. One point to keep in mind is that EDM machines are rather specialized and the parts can be expensive.

One shop I used to work in had four Charmilles sinkers. The maintenance guy knew of an individual who was apparently a service tech at some point. He had a lot of older sinkers that he had bought up and sold parts off of them. I don't recall a name, but I'll look in my stuff at work next week to see if I have any info.

Kevin

bborr01
04-24-2010, 12:22 AM
My brother spent 10 years or so in a mold shop. Big EDM's.
The nice thing about them is you can burn things you can't cut with cutters.
I recall him making a die to make speedometer needles.

I also recall seeing some huge electrodes for sinking molds. They would make the electrodes on a duplicator, burn them until the electrode lost its shape and then re-cut the same electrode until they had the mold burned to shape.

The carbon electrodes are easy to grind. In our shop we referred to them as erodes.

In our shop we had them mostly to burn more complex forms in cold forming dies.

You can burn threads into hardened steel. More than once I recall seeing someone make a detail and forget to put a tapped hole in or have one added to the design after the detail was already hardened. We would just burn threads into the details.

Also burned out a lot of broken taps.

We later got a machine that looked a lot like a light duty drill press for burning out taps. Seldom saw anyone use it.

Brian