Re: Tapered Threads in TurboCNC

Thanks for correcting me on that Kim. I have deleted the offending
post.

I thought it would be a sneaky way to only have one axis called on
the G33 line. Later I looked in the source and saw the check to error
if more than one axis is involved. Checked it on my lathe and it
definitely doesn't work.

Mark.

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Kim Lux <lux@d...> wrote:
> That absolutely won't work.
>
> I've made code modifications to G33 in TCNC, so I've seen first hand
> what it can and can't do. First of all, it will error if you put
more
> than one axis on the line, ie it won't take G33 X.75 Z-2. Secondly
it
> only does calculations for and loads and runs ONE axis to move in
synch
> with the spindle.
>
> I've spoken with Dave and looked at the source and it will probably
do a
> 2 axis synch move if I program it to. I'll probably work on this
over
> the weekend as I need it for next week.
>
> Kim
>
>
> On Fri, 2003-10-31 at 02:45, rotarysmp wrote:
> > If you really need to, this might (I haven't tried it) work to
> > produce a tapered thread in TurboCNC by taking advantage of a
couple
> > of it's quirks.
> >
> > TCNC 3.xx does not check for unique axis names, or for duplicate
axis.
> >
> > Duplicate your normal .INI, i'll call it Taper.INI
> >
> > Add a third axis, also called Z, which addresses the X axis
Step/dir
> > pins. We'll refer to this axis as fake Z.
> >
> > You would have to figure out the distance/step you plug into the
fake
> > Z axis based on the angle of taper you want to cut.
> >
> > When you call the G33, TurboCNC will drive both axis, synced to
the
> > encoder.
> >
> > If you have to do multiple cuts, your G00 X retracts and advances
> > will be as though on a parallel shaft.
> >
> > Example:
> > Cutting a 1:10 tapered thread with a 1mm pitch, 1mm deep from Z20
to
> > Z0 with in a 20mm dia shaft in four passes.
> >
> > The initial taper from Z20 X18 to Z0 X20 is previously machined
with
> > the normal.INI. Position to Z30 X18 before changing .INI's
> >
> > If your Normal.INI has an X axis distance per step of 0.01mm,
then
> > the Taper.INI would have the fake Z axis step to 0.001 for this
taper.
> >
> >
> > ;With threading tool point at Z30 X18 to
start
> > G00 X16.75 ;1st infeed
> > G33 Z0 K1 ;This will take you to Z0 X 19.75 although X
> > display will still be at X16.75
> > G00 X17.75 ;1mm retract
> > G00 Z30 ;This will take you to Z30 X17.75
> > G00 X16.5 ;second infeed
> > G33 Z0 K1 ;thread to Z0 X19.5
> > G00 X 17.5 ;1mm retract
> > G00 Z30 ;This will take you to Z30 X17.5
> > G00 X16.25 ;third infeed
> > G33 Z0 K1
> > G00 X17.25
> > G00 Z30
> > G00 X16 ;fouth infeed
> > G33 Z0 K1
> > G00 X17
> > G00 Z30
> > G00 X16 ;5th pass to clean up thread
> > G33 Z0 K1
> > G00 X17
> > G00 Z30 ;
> > G00 X18 ;Don't coordinate this with the line above,
or
> > you would have two axis's trying to address the same pins at the
same
> > time.Returns you to your start position, so you are at the same
point
> > you left your normal.INI from.
> >
> > Not really pretty, but should work.
> > Regards,
> > Mark.
> >
> >
> >
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> Kim Lux <lux@d...>