Re: [CAD_CAM_EDM_DRO] Re: Langlois EDM

Hi Dave:
The machine you're referring to is a Hansvedt.
I've got one.
When I burn with a 2 square inch trode, I'm using full power on the burn (25
amps at about 30 volts)
My burn rate is limited by the power I can put into the trode, and with
anything much over 2 sq in, I'm limited by the power supply of the machine,
rather than what the trode will take.
Lots of sinker EDM's run 100 amp power supplies and will use 30 to 40 amps
on a roughing burn of 2 sq in.
I don't think I'd be too comfortable running that amount of current through
the Langlois machine.
My comments were directed toward the utility of the machine...one of the
uses for which it was originally described, was for tap removal, and in
fact, one of the demo shots in his manual shows the removal of a stud from a
snowblower I think.
You may well be right that it doesn't do that function too well without a
very accurate Z axis slide.
Cheers

Marcus

----- Original Message -----
From: turbulatordude <davemucha@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Tuesday, April 27, 2004 9:23 AM
Subject: [CAD_CAM_EDM_DRO] Re: Langlois EDM


> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "Marcus and Eva"
> <implmex@a...> wrote:
> > Hi Travis:
> > If you're thinking of trying to compare this homebrew rig in
> any way
> > with a commercial sinker, you'll be disappointed.
> > Think of it as a tap disintigrator, but not much more than that.
> > You'll have a hard time trying to burn a mold cavity with it and
> achieve any
> > level of accuracy or productivity.
> > An 8 sq in electrode is way more than this unit can handle for any
> burns
> > deeper than a few thou, unless you've got a lot of patience.
> > Don't expect to be able to measure the burn rate in fractions of an
> inch per
> > hour on a 1"0. x 2" trode either.
> > Cheers
> >
> > Marcus
>
>
> I have to disagree with the conclusion to this. I built a Langolis
> unit and used different power transformers and different resistors
> and different voltages and such.
>
> Although I was severly disappointed, the burn rate has a lot to do
> with the power supply.
>
> I used a light bulb instead of the resistors. Start with a 150 watt
> and possibly go up to 1,000 watts. Bulbs are much cheaper than
> resistors.
>
> One of the things I found out was that the spark gap is so darn close
> that any vibration or play in the feed mechanism would wreak havoc on
> anything very deep.
>
> Once I fixed the slop in my Z, and used about 70 volts and a 150 watt
> light bulb, I used a brass tube, something on the order of 1/8 OD and
> gravity feed it with tap water.
>
> Much better results.
>
> Tried better water and got better results. Easily half the energy is
> lost in the water as my times doubled.
>
> As far as burning taps, and this is where I have a big disagreement,
> the closness of the wall and the electrolosys will have your
> electrode loosing huge amounts of energy just by being near the wall.
>
> Jon had the idea of a rotation electode and that will be on my next
> version.
>
> Obviously the current wire EDM articles running will offer much a
> much improved unit, and if you can put together the pusling power
> supplies instead of the R/C style, you will be far ahead of the game.
>
> I think I have figured it all out, but like everybody else, keep my
> findings very close to the vest. Of course, I don't know the mistakes
> that I'll make as once I got the tap burned out I put the machine
> aside for another day.
>
> Bottom line, the Langolis style EDM's are not tap burners. They are
> sheet metal decorators.
>
> If you have any interest in any real EDM work, keep your eyes on E-
> bay. A TRUE EDM will be on there each month and typically for less
> than $1,000.00. Halderstadt or Haberstodt or some such.... haven't
> looked in a long time, but the type are bench top. And if you have a
> real interest, buy the E-bay special.
>
> my 2 cents.
>
> Dave
>
>
>
>
>
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