Re: [CAD_CAM_EDM_DRO] Re: Auto tool changers

There's also the possibility (for semiautomatic use) of selecting the
desired tool by using a selector switch. All you'd need then would be an
on/off signal. that sounds like something I could work up for my Bridgeport
to use temporarily until I get the CNC gear hooked up. Would have to figure
out a way of building the mechanicals first.

Smoke

----- Original Message -----
From: "ballendo" <ballendo@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Saturday, February 23, 2002 5:12 PM
Subject: [CAD_CAM_EDM_DRO] Re: Auto tool changers


> Smoke,
>
> Sounds like a good plan. With 2 output bits you could DIRECTLY
> "select" 4 tools. With three bits, you could have 8 slots directly
> accesible.
>
> Hope this helps.
>
> Ballendo
>
> --- In CAD_CAM_EDM_DRO@y..., "Smoke" <smoke@t...> wrote:
> > Mines going to be a stand alone unit driven by hard wiring. I
> don't think
> > the unit needs to be programmable. All you need is a signal to the
> device
> > telling the unit which tool you need.
> >
> > Smoke.
> >
> > > Hi Bill,
> > >
> > > I can see two ways to implement control of the tool changer. A
> > > standalone unit driven by a PIC, or by a "canned routine" that is
> part
> > > of the controller. I could quite easily add a canned routine to
> my
> > > code, which wouldn't need the "handshake" that an external PIC
> > > controller would require. An offshoot of this effort could be a
> small
> > > program that would run on a "spare PC". It could a PC with only a
> > > floppy (or solid state disk), no monitor or keyboard. As small as
> > > possible. This is kind of a "black box" approach (good way to
> try some
> > > of that out). If a keyboard and monitor were supplied, a
> parameter
> > > screen could allow "tuning" the way the tool changer worked
> (positions,
> > > travel past stops, stepper parameters, etc).
> > >
> > > The PIC version is what I think you are interested in from
> previous
> > > conversations. The PIC controller would only need a pb or so, and
> > > perhaps a few LED's. The code can be written in C, however there
> would
> > > probably not be parameters that could be modified. A small LCD
> screen
> > > would indeed be possible, but would add to the complexity.
> > >
> > > What stepper driver are you planning on using? You could cobble
> up a
> > > unipolar drive. Four TIP120's, a 10 ohm power resistor, a 7400
> gate,
> > > and a 5V regulator would be about all you'd need.
> > >
> > > Do you have a stepper bolted up to the tool changer? If you do,
> you can
> > > try moving it with a controller program. This would determine
> worm
> > > screw ratio, gear ratio, etc. What we're interested in is the
> number of
> > > stepper counts for a full revolution of the tool changer head,
> and how
> > > far past the positions we must travel.
> > >
> > > Alan KM6VV
> > >
> > >
> > > wanliker@a... wrote:
> > > >
> > > > In a message dated 2/23/2002 11:17:44 AM Mountain Standard Time,
> > > > KM6VV@a... writes:
> > > >
> > > > > I am doubtful that the ratchet/paw mechanism on
> > > > > the tool changer would allow reverse rotation for anything
> other then
> > > > > "falling back" against the paw, and thus "shortest path",
> while
> > > > > interesting, may not be allowed.
> > > > >
> > > >
> > > > this is a correct assumption rotation is advance to position,
> reverst to
> > lock
> > > > into indexed/cutting position
> > > >
> > > > > From index, rotate 140 degrees,
> > > > > then fall back 20 degrees. How about videotape? Or a movie
> file?
> > > > >
> > > > >
> > > > With six tool positions it would be 60 degrees plus that
> required for
> > the
> > > > ratcher bar to fall. Then back that amount of overtravel plus
> maybe one
> > or
> > > > two degrees to insure stepper stall.
> > > >
> > > >
> > > > > The controller can wait for the
> > > > > M6 line "tool change" before the part program is allowed to
> continue.
> > > >
> > > > Don't forget to move the cross slide back to a tool setting
> position,
> > away
> > > > from any work in the unit incase you don't have all tools
> exactly set
> > right.
> > > > EMCO used a microscope to set all the tools to the same
> positions aimed
> > at
> > > > the tool points using cross hairs.
> > > > I will look up the site and send it later.
> > > >
> > > > Hope all of this helps.
> > > > bill
> > >
> > >
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