Re: [CAD_CAM_EDM_DRO] turret tool post for lathe

----- Original Message -----
From: Les Newell <les@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Friday, September 26, 2003 3:32 PM
Subject: Re: [CAD_CAM_EDM_DRO] turret tool post for lathe


> With my setup you can program the tool. The macro keeps track of the
current
> tool and when a new tool is selected the macro works out how many times to
> index the turret to select the new tool. If the macro doesn't know what
> position the turret is in (e.g if Mach2 has been restarted) it pops up a
> message box and asks you to enter the current turret position. At some
point
> I plan to fit a home switch to indicate position 1. This would remove the
> need for the message box.
>
> Effectively the turret is working as a slow and crude stepper motor. Apply
> one pulse and it moves one tool. The only advantage of using a proper
> stepper motor is that you can rotate the turret backwards as well as
> forwards which would make tool selection slightly quicker. If speed was
> really that much of an issue it would be cheaper and easier to fit a
larger
> DC motor in my turret to rotate it quicker. At the moment my turret takes
> about 2 seconds to index to the next tool - approx 1.5 seconds forwards
then
> 0.5 seconds back to hit the ratchet. As it holds up to 6 tools the maximum
> time to select any tool is 10 seconds (for example going from tool 3 to
tool
> 2). At the moment the motor is very small and ridiculously low geared. If
I
> fitted a large, low inertia motor or a pneumatic cylinder I am sure I
could
> reduce the time to less than 0.25 sec to index one tool.
>
> Les
>
> >
> > > Why use a stepper? The only advantage would be that you could index
the
> > > turret both ways. However you would either need a huge stepper or some
> form
> > > of locking mechanism to hold the tool in place while cutting. This
adds
> a
> > > lot to the cost and complexity.
> > >
> >
> > I would think that the advantage of programming the tool used, would
have
> > advantages. If the stepper drove the turret back into the locking
> position,
> > wouldn't the holding torque keep it there?
> >
> > bill
> >
>
>
>
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