Re: [CAD_CAM_EDM_DRO] Bridgeport CNC Mill???

"hanermo" - CNC 6-axis Designs wrote:

> Now, from the point of view of a user, for most it is immaterial how
> closely they servo tracks, as long as they make parts to tolerance.
> For example, for me as a user, I might make a part on a lathe, with a
> simple script/program and then mic it to check for fit.
> If the part is too large, slightly, say by 0.01 mm, I can then with
> total confidence move the tool 0.01 mm, do another pass (or 2), and be
> very confident I am much closer than 0.01 mm to the desired size.
>

Well, I rarely make a part this way. I program the part and make it,
and it comes
out right. I know about how much to offset for tool deflection, but
occasionally
have to adjust for it.

>
>
> This is one of the very, very good features of EMC2, that you can often
> analyse this (I have no idea whether this is possible with most advanced
> hw, and I believe generally you cannot do this [w. avd hw that is]).
> I believe that with most advanced servo cards/hw, you cannot see how
> closely the servo tracks during programs execution.
> I know it is possible with some hw combos, unfortunately it is again one
> of those things that are poorly documented.
>

You can connect a PC via serial cable to a Yaskawa Servo-Pak drive and
get real time
graphing of performance. I know the Allen-Bradley 8500 control could do
this.
Fanuc is very secretive, but if you know the secret passwords, you can
do this on most
of the recent Fanuc controls, too. You can also do it with Galil and
other servo
control cards for a PC.

For that matter, my Allen-Bradley 7320 from the mid 1970's had some
button next to the
screen. You could see the coordinates as position, distance to to go,
time to go and following error.
This didn't give you a graph, just an instantaneous number to read off
the screen.

But, these are all systems that were built from the ground up for
servos. MACH was built
from the ground up for use with software step generation, and any use in
a servo
system was an afterthought.

Jon