Re: EMC & Wire EDM? - archive

Hi Ray,

I know there are EDM threads in here somewhere, but the group name
makes every search a hit on every post !

I'm in the process of downloading the entire list into excel so I can
actually search the posts for the stuff I want to find.

It looks like a project for a database, but alas, I have no database
experiance.

It seems like there could be a wire edm software similar to the foam
cutting software for the single applicaiton.


Dave





--- In CAD_CAM_EDM_DRO@yahoogroups.com, Ray Henry <rehenry@u...>
wrote:

> On Monday 07 April 2003 10:59 pm, Dave wrote:
> > Message: 24
> >    Date: Tue, 08 Apr 2003 02:58:54 -0000
> >    From: "turbulatordude" <davemucha@j...>
> > Subject: Re: EMC & Wire EDM?
> >
> > --- In CAD_CAM_EDM_DRO@yahoogroups.com, "inetd_conf"

<benedict@h...>

> >
> > wrote:
> > > I've been considering tackling a wire EDM.  I'd prefer four axis
> > > control, but honestly I think I'd be doing good with two.
> > > 
> > > My CAM software will handle wire EDM just fine (yeah, I'm using
> > > Vector).  But I don't currently have control software that'll do
> >
> > the job.
> >
> > > 
> > > I was planning on building a power supply similar to the one

Robert

> > > Langlois described in his book published by Village Press.  In
> > > particular, I liked that it had a signal line that would go

high if

> > > the wire drew too much current (shorted), and another that

would go

> > > high if it drew too little (stopped cutting).  In his book,

which

> > > described a ram EDM, these two lines controlled the ram.
> > > 
> > > A wire EDM is a little more complicated.  If the wire shorts,

you

> > > don't just retract the ram, you have to stop or move the wire

back

> > > along the toolpath.
> > > 
> > > Ideally I'd like to use software that's designed with an EDM in
> >
> > mind.
> >
> > >  I'd like it to be able to listen for high or low current draw,

and

> > > act accordingly.
> > > 
> > > If anyone here has made a wire EDM, I'd be curious what your
> > > experiences were.  I'm not going to tackle this without a lot

more

> > > thought on the matter, so the more you can tell me the merrier

I'll

> >
> > be.
> >
> > > 
> > > Thanks,
> > > 
> > > Tom
> >
> > I've been thinking on the same lines.  what is needed is a

software

> > that will accept the input from the voltage monitoring circuit of

the

> > EDM to adjust cutting path speed.  the math of where to go is

done by

> > the software, but speed is dependant on the EDM circuit.
> >
> > Another feature you mention is cutting path reversal.  on a

sinker,

> > that is simple, one axis, but on a wire, it is 2 axis reversal.
> >
> > Some high end packages look ahead 150 steps of code or so, in

order

> > to maintain very smooth movements.  this would need look ahead
> > and 'remember' the last "X" number of lines for that reverse path.
> >
> > Master5/Mach1, has recently introduced the first step but it was
> > really designed for plasma cutting.  ie: the plasma cutting

circuit

> > moved the head up and down, but the software keeps tabs of the

exact

> > location.
> >
> > There is a need for this, and hopefully the answer is not in the

high

> > dollar software packages.
> >
> > Dave
>
> Roland (Cardinal Engineering) and I have been working on a plan to

retrofit

> his two axis Agie with the EMC. We've got the idea that it might

make a nice

> article for HSM. EMC is easier to do this with because it's source

is open

> and the price is just right.
>
> Monitoring two pins like you suggest and issuing feedrate commands

would be

> trivial with processes like tkio and iosh which are already in the

code.

> Watching an analog spark current signal is a bit more trouble but

still

> doable.
>
> Reversing using the g-code is not trivial if you are using wire

diameter

> offsetting but it would be fairly easy if we used a toolpath and

file routine

> like tkbackplot uses.
>
> There have been threads on control for this both here and on the

emc list.

>
> Ray Henry