Re: shaft torsion ?

Sorry I guess my terminology is incorrect. I assumed frictional
forces were included in machining forces. What about F = Mu.N, no A
some F. I understand that frictional forces are low in this kind of
machine, I was just interested to know if it has any practical
influence in the design and the selection of motor size.

Phil

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "carbonsteelsam"
<corryharper@...> wrote:

>
> Don't understand your view of "windup". At constant velocity there
> are no "loads" (F=MA; no A, no F). In a trued-up machine, at
> constant velocity, there would'nt even be a need for the cross

shaft

> (ignoring friction).
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "Philip Burman"
> <philip.burman@> wrote:
> >
> > My point was that there are "machining" loads, even at constant
> > velocity, that may cause "windup of the shaft. I was just
> interested
> > why this was not a problem in practice. I assumed it is due to

the

> > relatively low level of precision required with this type of
> machine.
> >
> > Phil
> >
> > --- In CAD_CAM_EDM_DRO@yahoogroups.com, "carbonsteelsam"
> > <corryharper@> wrote:
> > >
> > > Not unless they're overpowering your motors or there is an
> > extremely
> > > biased friction load from one rail to the other. With good

setup

> &
> > > alignment the rails should perform pretty much the same and the
> > > pinions would easily handle minor side-to-side fluctuations.
> > >
> > > --- In CAD_CAM_EDM_DRO@yahoogroups.com, "Philip Burman"
> > > <philip.burman@> wrote:
> > > >
> > > > Are frictional loads at constant velociy not an issue.
> > > >
> > > > Phil
> > > >
> > > > --- In CAD_CAM_EDM_DRO@yahoogroups.com, Kevin Martin
> <kpmartin@>
> > > > wrote:
> > > > >
> > > > > In the original message the system was described as "5 foot
> > wide
> > > > gantry on a plasma cutter" so there are essentially no
> machining
> > > loads
> > > > (unless you count the recoil from the plasma jet).
> > > > > -Kevin Martin
> > > > >
> > > > > -----Original Message-----
> > > > > From: CAD_CAM_EDM_DRO@yahoogroups.com
> > > > [mailto:CAD_CAM_EDM_DRO@yahoogroups.com] On Behalf Of
> > > carbonsteelsam
> > > > > [...]The real differential loads will result when the

router

> is
> > > to
> > > > the extreme end of its travel and is under heavy cutting load.
> > [...]
> > > > >
> > > >
> > >
> >
>