Re: [CAD_CAM_EDM_DRO] Handwheels on a retrofit? Why!? was Re: software questions DRO

We were talking about disengaging a servo motor and using an axis with ballscrews manually. The point I was making was not to have handwheels or not have them. Just bringing it to attention about an unpowered ballscrew and safety concerns. However, as personal preference I never use handwheels. I've had enough handwheeling to last me a while :-)

Ron


doug98105 <doug.rasmussen@...> wrote:
Guys,

Given a choice, I'd rather have handwheels than not. I don't think
I'd pay a large premium to have them as an option on a machine
though.

I notice Haas and Fadal have handwheels as a standard feature on
their new "toolroom" machines. LeBlond Machino had them on
their "toolmaker's" mill. Virtually all the makers of CNC flat bed
lathes have included handwheels. What do you suppose their
thinking was?

Incidently, all the above are electronic handwheels so the problems
Richard mentioned of machining with ballscrews do not apply. The
handweels as above require the control to be "on" to function.

Doug




--- In CAD_CAM_EDM_DRO@yahoogroups.com, R Rogers
wrote:

> The most important reason to not use a CNC machine manually is a

safety issue. A mill with ballscrews is unlike a mill with acme
threads in that: when force is applied to the table it will "feed"
the ballscrew. Acme threads have an inherent binding effect. Think
of a scissor jack. Try it, unhook one of your drive motors and push
on the table. Now turn the handwheel in the direction you are
pushing it will keep spinning. Push hard enough and it will gain
speed. So, if you are manual milling with ballscrews and a large
rougher and it grabs the work piece. The table will not hold
position on its own resulting in a very dangerous scenario. It's
best to operate as outlined below.

>
> Ron
>
>
>
> ballendo wrote:
> Kim,
>
> I completely agree...
>
> I just posted this on the turbocnc list; seems appropriate to this
> thread:
>
> Hello,
>
> How about these reasons:
>
> 1)"Jogging" is just power feed on all axes. Work all day without

your

> hand/arm getting tired, and feed more evenly than most can turn a
> wheel... AND "GO" faster than you can turn the handle.
>
> 2)Using incremental jog values you can easily stop on a dime... or
> a "tenth" if you will EVERY TIME... Need to drill a series of
> holes? set the distance as a jog increment, and a single keypress
> replaces precision turning of the handwheel...(especially valuable
> when the distance is something like .3794;or do you wanna do that
> addition in yer head?) of course with the CNC powered up, you have
> DROS, so you can reset zero instead... When you get where you're
> going, another keypress (Z minus) drills the hole...
>
> 3)With some controls, you can save each jog move to a file, so
> whatever you've done can be repeated...
>
> Hope this helps,
>
> Ballendo
>
> P.S. These things are why I don't understand the desire to keep
> handwheels in place on a CNC retrofit... This type of 3 axis,
> distance precise, powerfeed is what most MANUAL machinists WISH

FOR!!!

>
> I hear people saying, "I'll keep the handwheels for those jobs

where

> it's just not "worth" turning the computer on." Just what type of
> part is that?!? In windows, maybe;with its long boot time. But in
> DOS, I'll betcha I have the part more accurately made faster than

a

> person turning the wheels... The second argument is "feel", but

one

> learns quickly to replace this feel with other senses; much like a
> blind person relies on senses other than sight. I can smell, hear,
> see, and yes, even FEEL(place my free hand on the ways, and feel
> vibration, etc.), what the machine is doing...
>
>
> --- In turbocnc@yahoogroups.com, " T . Ackland" wrote:
> > I was of the impression that the jog is just used to touch the

work

> > piece with the cutter and then Zero'd or whatever figure you

want

> > to entered through the jog screen.
> > I cannot see the advantage of machining with the jog over

turning a

> > handle?
>
>
>
>
>
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, Kim Lux wrote:
> >
> > We just put electronic handwheels on our CNC equipment. By
> electronic,
> > I mean that the feedwheel is attached to an encoder and the

signal

> from
> > the encoder is fed to the CNC software, TurboCNC in this case.
> >
> > I think this is much more practical and powerful than retaining

the

> > mechanical handwheels. For example, one can operate in MDI mode,
> using
> > the electronic feedwheels to position the tool and then issue a
> manual
> > feed like drilling (G78) or straight feed (G77). With mechanical
> > handwheels, one would be stuck drilling or feeding manually. With
> > TurboCNC, one has feedrate override as well. The time this saves
> when
> > drilling and milling is incredible, to say nothing of being able

to

> > manually position and then do some arcs ie G02 and G03.
> >
> > Kim
> >
> >
> > On Mon, 2003-09-29 at 10:56, Jon Elson wrote:
> > > vlocci wrote:
> > >
> > > >I'm just getting started on a conversion and have a few
> software
> > > >questions that I haven't found answered in the archives. I'm
> inclined
> > > >to keep the handwheels on my mill, since I plan on the
> occasional job
> > > >done by hand.
> > > >
> > > >1) Assuming I use servo's with encoders, can I use the

encoders

> as a
> > > >source for positiong info that can be displayed within a
> software
> > > >package as a DRO? Which software packages allow this? Is EMC
> my
> > > >only choice?
> > > >
> > > >
> > > I think Mach 1 and 2 may support this.
> > >
> > > >2) Is the above possible with steppers instead of servo's?

Can

> it be
> > > >done without encoders? Which software allows this?
> > > >
> > > >
> > > How can you measure position without encoders?
> > >
> > > >I realize I'm limited by the accuracy of the axis ACME

threads,

> I.e.
> > > >backlash induced errors (a ballscrew conversion is in the
> future, but
> > > >I want to get things running first)
> > > >
> > > >Realize that I dont necessarily need CNC capabilities and the
> option
> > > >of manual DRO read out at the same time. (real time jumping

back

> and
> > > >forth) I'm only after the ability to either cnc a part
> automatically
> > > >(hands off), or elect to manually do things with a computer
> driven
> > > >DRO arrangement. Can this be done?
> > > >
> > > >
> > > Yes.
> > >
> > > >If it matters, I'm considering Gecko drives (either servo or
> stepper)
> > > >but am open to a change if it offers me DRO capability.
> > > >
> > > >
> > > You don't say what size machine you are planning on

converting.

> But,
> > > for the
> > > larger machines, it may be cheaper to go with servos, if you

plan

> on
> > > using encoders
> > > for DRO readout anyway. Also, sevo motors won't drag as much
> when you
> > > move the machine manually.
> > >
> > > Jon
> > >
> > >
> > > Addresses:
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> > >
> > > OFF Topic POSTS: General Machining
> > > If you wish to post on unlimited OT subjects goto:
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reach

> it if you have trouble.
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> > >
> > > http://groups.yahoo.com/group/jobshophomeshop I consider this
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> > >
> > > NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY
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> > > List Mom
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> > --
> > Kim Lux
>
>
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> Moderator: pentam@c... indigo_red@q... [Moderators]
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>
> OFF Topic POSTS: General Machining
> If you wish to post on unlimited OT subjects goto:

aol://5863:126/rec.crafts.metalworking or go thru Google.com to
reach it if you have trouble.

> http://www.metalworking.com/news_servers.html
>
> http://groups.yahoo.com/group/jobshophomeshop I consider this to

be a sister site to the CCED group, as many of the same members are
there, for OT subjects, that are not allowed on the CCED list.

>
> NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING

THEM. DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........

> bill
> List Mom
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