On 04/16/2021 12:30 PM, Gene Heskett wrote:
Greetings all;
I am still looking for a little help in rigid tapping.
Since the GO704 can only muster around 2 hp in its current drive
configuration, its often that I have to write a peck routine where each
peck goes just a fraction of a turn farther until the tap is deep
enough. But something is displacing it vertically just enough to make
noticeably sloppy fitting threads.
Yes, I can see how it could lose a count on each reversal.
But, then it ought to lose a count
in the opposite direction when the spindle reverses again,
correcting the first error.
I have to admit I have not done peck rigid tapping, so I
can't say if the same problem is happening on my machine.
I have a fairly low encoder count on my Bridgeport, 324
counts in quadrature/rev.
What is the resolution of your spindle encoder?
I do lots of rigid tapping in aluminum with fairly small
taps, 2-56 up to 10-32 or so.
I have no issues with torque on these, and I only have a 1
Hp spindle motor and VFD.
I do use Alum-Tap, which is a truly magic tapping fluid.
You can EASILY feel the reduced torque
when hand tapping aluminum, maybe half the torque as when
using cutting oil.
One other issue, could there be backlash in your Z drive? I
have less than .0015" backlash
in my Z drive. I can easily imagine Z axis backlash could
be a greater issue than which side
of the encoder pulse it is counting transitions on.
Jon
_______________________________________________
Emc-developers mailing list
Emc-developers@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-developers
