On 10/09/2016 12:26 PM,
chuckm@... [CAD_CAM_EDM_DRO] wrote:
I've been running my Bridgeport Interact II with Geckos
and Mach 3 for a couple years. ?Thot I had it pretty "dialed
in" - motor tuning set very close to 20000. Yesterday I
started a job that drilled a hole at 0,0, moved and drilled
holes at (+/-X,0) and (0,+/-Y) then returned to 0,0 to start
another part of the job. ?Even though MACH says I'm back at
0,0,0, the tool was visually off. ?I recentered and it appears
to have been off at least in X by 0.033", Y.. maybe 0.005 ish.
After recentering (visually) I cut a circle, which cut within
about 0.001" dia, and that's with no backlash compensation in
MACH.
Need help understanding this...?
Missing steps? - rapids were only like 15 ipm, "sounded
good" while moving, I was VERY surprised to literally see it
noticeably off center.
Backlash? - seems good based on the circle I cut
.033" seems way too much to be backlash.? I'm not a Mach user, but
any possibility you hit a wrong key and changed the coordinate
offsets or coordinate system by accident?? I've had a few crazy
things happen with LinuxCNC, and I'm pretty sure a few of them were
"operator error".? If you do it just right, these can cause small
offsets that won't be instantly obvious.? Some other crazy stuff
turned out to be a bad connector that had my motion interface
running on 4 V, when it was supposed to have 5.? Took a while to
even realize something was actually wrong, then took some time to
locate the bad connector.? It could be a bad connection that comes
and goes, possibly as the machine moves.? Those can be VERY
difficult to track down.
Jon
