toolchange idea for small mills wasRe: To tool change, or not...

Ballendo, neat idea using the Z axis to index the turret on a small
mill! (We suddenly have a benchtop machining center) A fully
automatic machining cycle would be possible.
Yes, I'm familiar with the turret lathe indexing as I spent a few
days "practicing" in my younger years. The Burgmaster drills used a
Geneva indexing mechanism that was relatively complicated with a
spring loaded drive clutch for spindle rotation. Their weak link was
the two helical hears running at right angles to drive each spindle.
The turret clamp ring would be crucial and could be released
(loosened) with a locking cam that engages near the top of the Z
axis "tool change stroke"
Another thought would be to mount the turret head on a miniature
rotary table like the 4th axis on the Maxnc, Sherline etc. Use the
stepper or servo to index the turret as well as position to any
machining angle. Problem here is we're starting to hang a lot of
weight on the Z axis but imagine the possibilities. Could really
make use of the multi axis capabilities of the upcoming Master6.
Nelson

--- In CAD_CAM_EDM_DRO@y..., "ballendo" <ballendo@y...> wrote:
> Nelson,
>
> I saw a photo some years back of a machine which used this concept.
> It was a cnc pc board drill, and was about the size of a maxNC 10.
> The then current model was single spindle, and this photo was
thrown
> in as a "coming attractions" enticement. Never did find out if it
> made production... But often think of that pic. (NCF-1000, maybe?)
>
> You could get away from manual indexing by using the z axis
to "make
> the change". Are you familiar with the old turret tailstocks used
> with metalworking lathes? Typically six-sided, they are indexed by
an
> away-from-the-headstock rotation of a 3 or 4 rod "handwheel" (like
a
> drill press quill handle). What is happening inside is that a fixed
> rod or casting "bump" is hitting a peg(one of six) on the underside
> of the tool carrying hex-shaped block. Continued movement indexes
the
> head(since the rod and the pin are off to one side of center), and
a
> system of locking for the cut is also provided.
>
> I think this would make an excellent design model for a MaxNC
turret
> head. The action would be to raise the z axis upward, which would
> effect the index. Moving back down would set the lock. For the
price
> of a little "lost" z axis motion, a tool/head change! And no change
> to the s/w package necessary. You just add the upward move, AND
keep
> track of what tool is where... (position of the hex head, so you
> can "bump" the correct number of times to get the tool you want)
>
> Hope this helps.
>
> Ballendo
>
> --- In CAD_CAM_EDM_DRO@y..., "npp67420" <npalen@n...> wrote:
> > Doug--The idea of a turret type tool changer on a little benchtop
> > mill might have some merit. It was discussed briefly on the
Maxnc
> > forum a couple months back. The Burgmaster concept makes for a
> very quick tool change.
> <snip>
> > I'm wondering about taking it a step further and making an
indexing
> > turret head with at least four, possibly six, spindles ala
> Burgmaster etc.
> > In order to be cost effective the indexing would probably have to
> > be done manually with the spindle stopped.
> <snip of details>
> > Nelson Palen
> >