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
>