Good day folks,
We've been experiencing a troublesome servo creep, which results in out-of-square cabinet parts somewhat intermittently. About half the sheets we cut are just fine, and about half have parts that are anywhere from "almost square" to 2-3mm out of square.
This happened to our X axis last winter, but were able to isolate the problem to a faulty motor drive card, so we replace it and the problem went away. A few months later, it started happening on the V side.
I have talked at considerable length with the tech support at CNT Motion but seem to have exhausted almost (almost) everything they can suggest.
Here is what we've found through observation and the use of servo-tune software. We will home the machine and calibrate the servo-tune software to reflect "motor position 0" and then we'd cut a sheet, and then command the machine to go to position Y0. The resulting motor position tells us if it's going back to 0 or not.
About half the time, it goes back to 0. Other times it's out as much as 2-3mm (which explains why some parts are 2-3mm out of square).
X and Z axis has been checked, as well as the Y-side servo. NONE of them give us any creep. They always return to 0.
1) The problem always, always happens on the V-servo side of the machine (Y axis has two servos, the V and Y servo).
2) We have tried three different motor drive cards on the V-servo side, no change. Thus I think we can rule out the card. One of those cards is hardly 8 months old.
3) We have put every servo motor on the machine in the V-location. No change. V side still creeps, none of the others do.
4) Replaced the pigtail wire that goes from the V drive card to the V motor. No change.
5) Replaced the main pigtail wire that goes from the CNC computer's main PC Cabinet to the actual CNC itself. No change.
6) Ran test cuts (empty spoilboard) with dust collector physically disconnected from the router, vacuum pump off, and every electrical device (including overhead lights, edgebander, etc) turned off. Trying to see if there's perhaps interference from electrical devices causing this. No change.
Any suggestions? I'm happy to answer any other questions related to this.