Re: [CAD_CAM_EDM_DRO] Re: Software for wire EDM control?

Jon,
I wish I knew. There is no internal documentation--they would not even sell it!
Now Hitachi is out of the biz. We have learned a little having to repair it on
our own, but so far the troubles have been relatively simple. Presently the
X axis servo motor is in trouble and at a servo repair shop for diagnosis.
I can tell you how the machine works from a use standpoint, features, etc.
The mechanics of the wire feed can be useful. The work area is about 24" sq.
The control cabinet is 5' high, 5' deep and 3' wide, full of electronics.
The wire cutting speed depends on the cut conditions as it progresses. Each
type of material has a programmed setting range of values to refer to.
You increment the setting manually while watching the speed display and listening
to the arc. If no improvement in speed can be forced, it is left to proceed as is.
Any further increase may result in burning off the wire. The program halts.
It works like any cnc machine would except the actual cut speed is controlled
by sensing the voltage and current in the wire circuit. I beleive there is a
low voltage and current always on the wire to sense the wire condition
(grounded or broken, etc) and in the cut process the high voltage is applied over that.
Flush nozzles surround the wire guides and are brought very close to the work piece.
Water is pumped in from above and below and is drained off immediatly. No submerge.
I have pics of the control panel and wire mechanism if anyone wants (offline).
RichD

Jon Elson wrote:

>
> RichD wrote:
>
> >Alan & Jon,
> >I have used the Hitachi WEDM (1994 model) many times at school. It is old
> >and does not have all the bells & whistles that the new ones have (thankyou!).
> >We use a plain g-code prog (no g0, z, or tool calls). Only coordinate positioning.
> >It is 4 axis, but we have not learned how to use the U-V as yet.
> >It does auto backup when a problem with the cut is sensed to retry for a good
> >cut. This happens sometimes at the end of a cut when the scrap drops and fouls the wire.
> >Auto tracing to retract or retrace/restart a cut is a feature.
> >It cuts thru any metallic or conductive material. The fastest I have seen is about
> >.2"/min. thru steel. We use plain tap water flush as Atlanta water is almost
> >mineral free. Cuts are very smooth and predictable.
> >Wire is hard brass .010" dia. fed continuously thru tensioning rollers and saffire guides.
> >Power is applied to the wire via graphite rubbing blocks.
> >If anyone would like info or pics to help design a home built, just ask.
> >There is no internal documentation available, but a user manual 4" thick!
> >We have been repairing it ourselves, so know a little of the guts of it.
> >
> >
> I guess this is asking for trade secrets, but if you can describe how the
> pulser system works, that would be helpful.
>
> Jon