Re: [CAD_CAM_EDM_DRO] re:Re: lathe arcs

Doug: I just came from the shop(garage) after trying a file using interpolatated arcs using .002" segments. The lathe drew out the
right profile. Looks like the best way for me to go for now. I tried the interpolation a day or two ago but at .001" segments. I had
to shut the 650mhz computer down after 50+ minutes trying to generate the drawing. Using this method will probably insure a closer
match on the opposing roller as well. The rollers are 9" long and will put sort of a corrugated shape into the panel. I can't say
what they are for. My client has applied for a patent and just last week (while I was in Utah skiing) discovered that his metal
supplier has a patent pending on a similar product. But they spent multiple millions to get theirs done fast. Oh well. we will see
what happens. Thanks for your help, Carey

dougrasmussen@... wrote:

> Carey,
>
> Can you break your arcs down into a series of short straight line
> segments? Not the best way to do the turning, but might get you out
> of trouble until you find the cause of the problem. Keep the
> segments short and you won't notice the difference between continuous
> arcs.
>
> Sometimes I have to do the same thing on an older Emco production
> machine with steppers. Emco limited the programmable arc radius to
> something in the 5" range to eliminate possible stair steps on the
> part due to machine resolution.
>
> BTW, what are the rollers for? I turn special rolls for my power
> beading machine once in a while.
>
> Doug
>
> --- In CAD_CAM_EDM_DRO@y..., "Carey L. Culpepper" <mr.c@b...> wrote:
> > Ballendo: The machine still makes the original "angular" rollers
> perfectly. Actually it will do the roughing passes on the parts
> > with arcs until it goes for the finish pass. Then it goes nuts.
> Everything looks good until it hits the code for an arc. Sometimes
> > it just keeps going straight. Other settings did a chamfer instead
> of an arc.Nothing resembling an arc.
> > I did cheat the system by using the CNCPro driver and reconfigured
> to use x-y axis (easy to do with cncpro-tis in the setup,no
> > changing wires) and did use G18. Same bad stuff but I had to try
> it. Doug emailed me back and recommended trying relative
> > coordinates. Then it followed an arc but didn't cut the part the
> same as the drawing. I found trying to use relative coordinates
> > difficult to set up where to set the tool to start to wind up with
> the correct diameter. I did take some time and made up a
> > penholder that is held in a magnetic base to draw the part on paper
> so I would get a hard copy of where the machine was going. I
> > have tried a lot of things -drawing in different quadrants-changing
> axis direction-cutting direction. I have tried so many things
> > that I am probably duplicating attempts. It will probably be a
> driver setting that is the problem. I sent Don a screen print of the
> > driver setup and the roughing finishing setup windows. Waiting to
> hear back . He had to work till noon today. I am about ready for
> > the looney bin at this point. Thanks,Carey
> >
> > ballendo@y... wrote:
> >
> > > Hi Carey,
> > >
> > > Don's probably got ya covered, but just in case...
> > >
> > > First, Can you correctly make the "previous" rollers now!? Using
> > > whatever means you used before? If so, then you know there is no
> > > change in the system functionality. If NOT, then you know to look
> at
> > > ANY changes made since they last ran correctly. I would keep
> trying
> > > to run them until they are cutting correctly; THEN go to the "new"
> > > stuff.
> > >
> > > Don mentioned G18. You could also use g17 (xy plane for arcs)
> > > and "cheat" by changing the cables to the motors.
> > >
> > > Sorry I can't do more than this. I have mentioned in the past
> that I
> > > have experienced some "strange" output from CncPRO... usually
> > > excessive Z motion. Would this correlate to your problem? I.E.,
> the
> > > arcs are ellipses or worse, jagged ellipses?
> > >
> > > Hope this helps.
> > >
> > > Ballendo
> > >
> > > --- In CAD_CAM_EDM_DRO@y..., "Carey L. Culpepper" <mr.c@b...>
> wrote:
> > > > I am in need of some help. I am doing lathe work on my cnc
> converted
> > > > Hardinge hlv-h lathe. I am making forming rollers for
> specialized
> > > sheet
> > > > metal shapes. The first sets of rollers were strictly angular
> flats
> > > and
> > > > angles. The next stages require arcs (fillets). I cannot get my
> > > machine
> > > > to cut the arcs. It machines all of the flats and angles
> perfectly
> > > but
> > > > does weird things when it gets to the arcs. The drawings and
> gcodes
> > > are
> > > > Vector 8.2 generated. I even went back and altered a previous
> BobCad
> > > > drawing(which was used to make the previous rollers without
> problem)
> > > > with some fillets. Same type of problem. I have been working on
> > > this for
> > > > several long frustrating days. I have talked with Fred and tried
> > > some
> > > > things and emailed Doug and tried doing it with relative
> coordinates
> > > > which did result in some arcs but still not accurate to the
> > > drawing. I
> > > > am using CNCPro as a control program. I have tried drawing in
> > > different
> > > > quadrants, all manner of different things- all wrong. This is
> > > probably
> > > > something really simple as far as setup(to the experienced
> > > operator) but
> > > > I just haven't found it yet. I made up a pen holder to draw the
> tool
> > > > path on the lathe and have gotten some rather unusual shapes.
> Fred
> > > and
> > > > Doug have been very helpful but it is the weekend and I am
> > > desperate.
> > >
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