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