EDM uses for HSM

sale.

I got my sinker EDM out of curiosity - It didn't work and I like a challenge. Now it's working fine it doesn't get used often, but when it does it's SO USEFUL ! Examples:

a/ Removing broken taps (loads of friends bring them to me!) b/ Cutting though a hardened R8-> MT adaptor for a draw bar c/ Making square holes for handles d/ Making split hexagonal dies for a cable crimper e/ Making larger holes in indexable tips to fit my holder etc etc etc

If the EDM fluid is synthetic it costs a bomb. I paid more for my fluid than the machine as I didn't fancy 19 gallons of smelly inflamable parrafin in my garage !

AWEM

There is NO ONE HSMer. Some of us make tiny models, some make exotic aerospace or medical tooling, some fix bulldozers and farm equipment, some mechanically etch circuit boards. So, if you have an interest in cutting really hard stuff, go for it. If it is hydrocarbon dielectric, make sure your fire insurance will pay off if there's a fire (not a snowball's chance in hell, of course).

Jon

Certainly a fair statement. But knowing what others have done(or do), I can make a decision if that is relevent to me.

Depends on your insurance. I don't have "typical" home insurance anyways. I imagine this could be difficult to explain in a home setting. But doesn't really apply to me. Good point to mention though.

JW

I used mine to build the mold for my Taco Tender. They are useful for burning out taps, and other materials too hard for normal methods. They create sharp corners, and can even shape carbide.

And it's worth it to pay the bomb. As an executive of a well-known EDM manufacturer once told me (facetiously), he had no trouble identifying the toolmaking shops in third-world countries when he flew in to them at low altitude. He'd just look for the plumes of smoke.

Parrafin (kerosene) in an EDM works great, and turns your machine tool into one hell of a torch.

-- Ed Huntress

You lucky dog. I'd love to get a ram EDM cheap. I used to work an an EDM shop in the late 70's to early 80's. The ELOX is/was a great ram, just make sure the servo valve works. What type of power supply comes with it? An ASTRA T200D would be kick-a**.

It has a TCV-50 with it.

How do I determine the servo valve is working correctly?

JW

I have a sinker EDM and I wouldn't recommend it for a HSM. Matter of fact if I could sell mine and recoup my costs I would.

EDM is high maintainence, with special pumps, filters, and electronics. The dielectric fluid is expensive. To replace it consider spending $500 - $1000, and it doesn't last forever. I had to have my servo valve rebuilt at a cost of $800, and don't plan on rebuilding it yourself, you need a specialized shop that handles that with flow bench. Hope that your valve is rebuildable and not obsolete. Hope your power supply electronics hold up and don't require factory repair, unless your good at trouble shooting electronic circuits, testing capacitors,relays, diodes, and other goodies. Any microprocessor stuff hope that they still sell parts and you may pass out at the price tag.

You have to make your own tooling, and machining graphite electrodes is messy. Electrode and tool holders need to be properly designed with flushing passages to operate correctly. Burning taps doesn't always work out as planned, I've damaged some jobs when the electrode shorted , you see a big flash of light under the dielectric and find your workpiece got charred & melted.

They take up alot of room, (power supply, fluid tank filter & pump, Hydraulic power unit, and Ram + tank)and are prone to leaking hydraulic oil or spillage of the dielectic fluid from the tank top.

There's a big learning curve unless you have prior job experience in operating the EDM and setting up, proper flushing, amount of capacitance, polarity, mode.

The process is very slow, don't expect to sink a hole in a few minutes like would with a twist drill. By the time you set up your part, get the machine ready (fill the tank, hook up compressed air, replace electrodes during job) and run the job it could be a few hours (not including fabricating the electrodes).

Be wary of dreams to EDM carbide, due to carbide's high melting temperature, you will experience slow burning and high electrode wear. It usually requires a late model power supply that can handle such jobs, usually not the stuff your gonna find surplus.

Before you buy a used unit be sure you see it running & burning under power to be sure everything is working.

I have a Hansvedt 15 amp sinker EDM in NY if anyone is interested.

Tony

I have a sinker EDM. Guess I've been lucky. My main expense after purchase has been for graphite and copper electrodes. I use it 2 or 3 times a year on things that can't be done any other way.

I've never got real proficient at running it. I'll never be able to make a production mold. But for all the jobs others have mentioned, its indispensable.

I just bought a wire EDM. In fact, I plan to do the first burn tomorrow.

And a Hansvedt would be a relatively simple and compact HSM machine. (Is yours a tabletop model?).

I'm not an experienced EDM operator but I've sold a few and operated several makes and types on the showroom floor. On that limited basis I second your opinions. However, they can be a lot of fun for someone who just likes doing things, rather than having done things. In other words, some people find operating and fussing with an EDM to be fun in itself. It's just going to cost more to run than most people realize.

If I could find an old Sodick Moldmaker (A30?), and if I had the room and wanted to spend the cash for dielectric, etc., that would be my choice. It had stepper motors and ballscrews for positioning and for servo action on all three axes, so there was no servo valve and no hydraulics. Reports at the time, which was the early '80s, were that the simple CNC that runs everything on the machine is pretty well bulletproof.

-- Ed Huntress

Ed,

I bought my machine years ago and I've just used the fluid that was in it. I got an extra barrel of something labeled "EDM". I've not seen more than a puff of smoke in use.

How can I be certain I don't just have kerosene? Just put some on a rag and see if it lights right up with a match?

Karl

"Karl Townsend" wrote in message news:wv6bh.5124$ snipped-for-privacy@newsread2.news.pas.earthlink.net...

Haha! I don't know how to tell you for sure. Commercial EDM dielectric fluid has stuff in it to keep it from smelling like kerosene, for one thing. It has flash suppressants that, when it's reasonably fresh, suppress fire.

If you put it on a rag, my guess is it will burn either way. If you put some in a can and if you can light *that* with a match, you have a problem.

Maybe someone who has experience with old EDM dielectric can help here. I've always had the luxury of using fresh fluid.

Keep that fire extinguisher handy...

-- Ed Huntress

Hmmm... SWAG: Perhaps a layer of cheap heavier-than-air shielding gas (CO2) floating over the kerosene in the EDM work tank would help?

No oxygen, no fire triangle, QED no fire. (Or a lot less if the EDM arc is electrolyzing some oxygen from the kerosene.) Yes no?

-->--

That's how the accessory automatic fire extinguishers for EDMs work, or did work, when I was in the business. They were CO2 fire extinguishers that blanketed the tank, when they were tripped by a fast-acting thermostat.

I have heard something about running full-time with a blanket of something -- maybe nitrogen -- but it's all fuzzy in my memory (what else is new?). I'd be surprised if they did that with an ordinary EDM, though, because a continuous flow of CO2 or nitrogen would pose a danger of displacing oxygen over a large area, as it ran over the top of the tank.

'Dunno. You could ask someone at one of the EDM aftermarket suppliers.

-- Ed Huntress

Perhaps maintain a blanket of inert gas over the kerosene?

in

dielectric fluid

thing. It

problem.

My synthetic EDM fluid ( IONOPLUS by OEL-Held ) is fluorsecent green, odourless, and despite trying to set a rag dipped in it on fire I cannot.

AWEM

electronics. The

$500 - $1000,

specialized

rebuildable

electronic

charred &

hydraulic oil

capacitance,

minutes like

jobs,

under power

Bah HUMBUG !

When I got my Agimaspark (Eurospark) H425 in non working condition I had never used or even set hands on a working EDM, and had no circuit diagrams just a user manual. Common sense and a few nights of head scratching worked out what it was trying to do and how it did it. Tracing circuits and a bit of research got it going. It comprises elements of electronics, electrical power, normal mechanical engineering and hydraulics non of which is beyond a half intelligent hobbyist.

That's what HSM is all about - finding out how to do things - mending things - running things on a shoestring. I'm not suggesting it's a commercial aproach but it is HSM, and it's fun

AWEM

Its been too long ago , so i wont garantee ....

i think we used kerosene and D.I. water and somethin else .

so maybe you can blend K' to make it less costly . Maybe we filtered it and recirculated it .

i remember in the big hanger at Edwards AFB , 6515 FMS

in 63 ? we took out a broken tap from a huge engine casing . but then it sit idle after that .

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Then the loud speakers announced everyone must stay away from the runway , for they were going to fly a secret airplane ....then a captain came into the sheetmetal shop and asked if anyone wanted to see the A-11 fly ! But , but , but they warned us away ? He said " no problem ,i work on that project "

It was the first stealth ever , the first blackbird . It had green tires and made lots of noise and teetered off the tarmac at an very hi pitch angle , maybe ? not enuf power ? ....

jw wrote:

How much you got to spend?

I've got a real nice little unit I'd let go for $3,500. It's a Hurco with an Eltee Pulsitron control. It has an orbiting head so you can burn undercuts and threads. It has a nice digital read out, and a drop tank to make loading the table easier.