Copper Electrodes pros and cons???

[lou]

My Company is pushing me to try Copper for my electrodes insted of graphite. What are the pro's and con's?

 

Is anyone doing this now?

 

Thanks for your input! Lou

[Charles Davis]

Copper is a lot cleaner to work with.

 

[ 01-09-2004, 12:26 PM: Message edited by: Charles Davis ]

[d00d]

We use graphite exclusivly now. It doesnt wear as fast as copper, cutting time on the trode is faster. But I think it is more expensive.

Use poco3, dont let a sales person talk you into "something as good" as poco3. We have went through many headaches due to this.

 

[ 01-08-2004, 04:33 PM: Message edited by: d00d ]

[Tony]

Straight copper or copper impregnated?

[mold100]

Every application is differant, I stray as far away from copper as possible, I had to use it last week for one job but its expensive, tooling doesnt last as long and try roughing it with a

1/2 flat 9800 rpms and 650 inches per minute.

 

I prefer if nescessary for wear, more overburn.

of for detail poco af-5 or equiv. or copper impreg.(c-3)

 

Thermal Conductivity of material is also a issue,

copper or preferably coppper impreg is good for beryllium.But that all I will recomend it for.

 

What is the issue for wanting to make a switch?

 

These are only my opinions.

[Racer X]

I agree. Copper is better if you are trying to achieve a super fine finish. However, if you use a good grade of graphite (poco 3, AF5) you can get really close to what copper will do. Graphite machines faster and wears less.

[Jack Mitchell]

It should go without saying, but what the heck.

Use a graphite roughing electrode to boil out the cavity and a finishing electrode to for sizing and finish requirements.

Copper is nice for finishing but not essential.

 

About 15 years ago I asked a customer why they were using copper instead of graphite to machine their moulds. – He responded by saying that they had thought about this before but had always done things like this - in the manner they were using.

He asked me about the settings and I simply replied just install the electrode and boil it.

Two months later he had about ten thousand dollars worth of impregnated carbon at the machine.

He told me he was ashamed to admit the thousands upon thousands of hours wasted with copper and thanked me profusely for suggesting it.

Funny thing is that I have never operated a conventional burner – just made many electrodes and still to this day despise cutting carbon for the shear mess of it all.

 

Regards, Jack

 

 

 

Regards, Jack

 

[ 01-08-2004, 07:24 PM: Message edited by: Jack Mitchell ]

[Müřlıń®]

I have used alot of metal electrodes in RAM type EDM's

 

Solid metal copper electrodes:

 

Pro's

Copper electrodes are stronger when you need to burn a small deep burn.

 

Copper electrodes last a long time and are not prone to breakage if there are to be thin walls or small electrodes. (bumping or dropping them wont break or chip them)

 

Copper electrodes are more resilliant to arcs.

 

Copper electrodes are cheaper than graphite.

 

Con's

 

Flush holes are obviusly harder to drill.

 

Copper electrodes are more difficult to machine and polish.

 

 

Now if you are talking poco....

 

copper poco is alot stronger and wear resistant.

 

But it is very expensive.

 

Murlin

 

[ 01-08-2004, 08:57 PM: Message edited by: Murlin ]

[lou]

THANK YOU for all the resondses!!

 

Tony, Straight Copper

 

Mold100, I was looking into a graphite machine and I was ask if we could just use copper for electrodes and just cut it in the regular mills instead. I never used it before but I figured somebody it out there doing it. So, I will take all the input you guys can give me to help make my decision.

 

Thanks again, Lou

[kkominiarek]

I believe in Europe and Japan copper is the norm and in North America graphite is the norm.

 

If you are going to copper is it straight copper or Telco (tellurium copper), Hard Drawn copper, CT-3 (copper tungsten) or even Free Cutting Brass.....all have different machining characteristics and wear patterns.

 

.....food for thought

[lou]

Hi Ken,

 

I am open to the type of copper I would have to use also. I will be cutting them on new makino s56's and running them on Misubishi AE5 or possibly OLD ex-cell-o sinker EDM's.

[Kevangel]

My experiance with electtrode materials is :just because it costs more does not mean its better,depends more on the application, for most jobs the cheaper graphite not only machines faster but seems to burn faster in the real world.My experiance is limited to conventional sinkers-25 years mold making and general tool work.

[Müřlıń®]

quote:

---

for most jobs the cheaper graphite not only machines faster but seems to burn faster in the real world

---

+1....gotta love that cheap EC3

 

 

Murlin

[mold100]

Ken,

 

Are you still at MWI?

[chip]

I've pretty much only used graphite......The thing I have trouble with is we don't have a machine only for graphite. When I cut graphite that s@#t gets everywhere! I do notice a difference between (i.e.) U.S.700 to poco 3. I don't have to re-dress the electrode sometimes at all.

 

Here at the company I work for, they have a lot of copper electrodes, I've only been experienced in graphite.....good luck!