Handwheels again?!? was Re: true closed loop vs. hobby closed loop

Hello,

At first, this seems like a valid argument. But...

Do you realise that the feedback you got "by hand" with your carbide
endmill and titanium material is most likely TOTALLY misleading?

Because CNC does not operate at "Handwheel" speeds... Especially with
the new cutter materials and geometry's...

So while you're "getting a feel" for how titanium machines with your
new cutter, you're probably ALSO work-hardening the titanium. AND
dulling your cutter due to heat generation at the cutting edge. Which
means that you will be totally misled. And then use feeds/speeds
which not only ENSURE poor tool life and material performance. But
also keep you from embracing the way this is handled by professional
machinists these days...

Cutter charts. Mfr.s reps(App engineers).

FWIW, they'll answer "hobby" cnc questions too!

Ballendo

P.S. Why do you think it's better to make that "should've been sawn,
but cut with an endmill" pass by hand, rather than using a jog or
MDI? My "quick-and-dirty" cut using either of these will be of better
quality than yours, AND put less stress on the cutter and material.
And I'll finish first TOO! ESPECIALLY if we both need multiple passes
to get through the material.

Handwheels on a CNC machine are like training wheels on a bicycle. At
some point they become crutches, which keep you from USING your
bicycle(or CNC MACHINE) to its fullest...


--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Abby Katt" <abbylynx@y...>
wrote:

> I think despite the fact you could rig up some encoders to jog the
> mill for you, there is something useful about the actual feedback

you

> get from manual milling. I started with CNC and never really got an
> idea of how much force was needed to perform various cutting
> operations. The first time I actually disconnected the motors from
> the controller and hand-jogged the mill, I realized how powerful it
> was. Sometimes when I'm cutting new materials (I was playing with a
> Tungsten Carbide cutter and some Titanum the other day) it's really
> nice to be able to get a "hands-on feel" for how the mill is

cutting

> the material without pinging an end-mill or stalling your drive.

Most

> hobby CNC really has no way of telling you how "hard" something is,
> or how confident you should be when cutting U-deep at V-feed... but
> you can find out in a few seconds by hand-cranking it.
>
> And it stills seems miles faster to do it manually when I'm too

lazy

> to saw something and just cut it off with an end-mill. :)
>
> My 2p (3.6c) :)
>
>
>
>
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "ballendo" <ballendo@y...>
> wrote:
> > Kevin,
> >
> > You have CNC. Why on earth would you need handles?!?
> >
> > And just think, the Bridgeport engineers left them off of

hundreds

> of
> > machines... (Were they dummies to do so?) Bacause they
> > certainly "could have" left them on if they thought there was a
> > reason... (It's not like they didn't have them "available" in the
> > Bridgeport factory!)
> >
> > I'll never understand this idea that handwheels are somehow a

good

> > thing to have on a cnc machine. I've laid out the reasons I feel
> this
> > way many times before; so I won't repeat them here...
> >
> > Suffice to say that being able to move in any given increment, at

a

> > speed faster than I can turn any handwheel, and stop on the EXACT
> > spot I desire repeatedly, for me at least renders handwheels
> > unnecessary... (and a safety hazard)
> >
> > Ballendo
> >
> > --- In CAD_CAM_EDM_DRO@yahoogroups.com, "Kevin R. Walsh"
> > <krwalsh@y...> wrote:
> > >Anyone have any luck fitting handle to the old Bridgeport CNC
> > machines? I can easily get one on the Z drive. The Y drive I
> could
> > maybe see how I can modify the belt cover and put a handle in.
> What
> > about the X?
> > >
> > > Thanks
> > > Kevin