> -----Original Message----- > From: gene heskett [mailto:ghesk...@shentel.net] > Another way (the rattle is often because the encoder feedback is too > coarse) is to improve the encoder definition. I had a shop made optical > with 64 slots per rev, and my spindle sounded like every ball in the > bearings was square, a very worrisome racket. So I made an extension on > the rear of the motor shaft to drive an Omron 1000 ppr encoder mounted > on the rear of the motor.� But left the index on the spindle. The Omron > had a balanced output which I turned to TTL by a couple $2.00 rs485 > translators.� That was too fast for the parport cards opto's, so I moved > that to the 5i25's encoder which has no glacial opto's. Then I put a > couple switches on the go704's gearshift knob to tell LCNC which gear it > was in. I now get 3000 revs in high, or 1500 in low with a switch in hal > to change the scale, which is a bit over 7000 in high gear, and a bit > over 14,000 in low gear. > > This totally got rid of the servo slapping the gears around, which is > what was making all the noise. Wasn't square bearings at all. > Cheers, Gene Heskett, CET. > > --
Thanks Gene, I could use the encoder outputs from the spindle AC Servo. It's 2500 lines or 10,000 edges per rev. But I want to use the spindle for power tapping and I don't think my pulleys plus belt are exactly 1:1 hence the 60 slot disk on the spindle. Pretty sure power tapping needs to know the exact speed in order to track the Z axis. And when I made the encoder I designed it for a 3mm end mill but accidentally used a 4mm end mill. So the slots are 3mm and the teeth are more like about 2.5mm so the quadrature square waves are not symmetrical which likely doesn't help either. My intention, after ball screws on XY is to make new pulleys for a toothed belt so I can have correct 1:1. I've found the Bergerda 1800W AC Servo has more than enough torque at low speeds for what I do so I don't need a two step pulley setup. And therefore I can add a second toothed belt and smaller pulleys to the spindle and an encoder. John _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
