On 1/24/23 11:07, Sam Sokolik wrote:
This is why I don't like smart servo drives.. lol.. You don't know how well the drive is following the path linuxcnc is commanding..
My experience has been the opposite Sam. I have no PID's in the config to run my Sheldon 11x54, I put a 3NM on the Z cause the carriage weighs around 20 maybe more pounds. In all cases here I'm using the 3 phase version, turns 1.2 degree per full step cycle.
But I didn't have room for the length of a 3NM behind the new apron, so I put a 2NM on to drive X.
I took off a 1200 inlb nema34 as it could only do a g0 at 60ipm on a good day, and took a nema 24 off the x because its max w/o a stall was maybe 29 ipm on a good day. And both were noisy as can be.
With the 2 nema-23 3 phase stepper/servo's, Z now moves at 120 ipm, and x moves at 60 ipm, and at working speeds cannot be heard, only the belt swish driving the spindle. Like watching Casper the ghost turning the cranks now.
I can position a chuck jaw to be hit with a missdirected tool at 10 ipm, it hits the jaw sees the stop, and stops lcnc in about a millisecond. The chip in the tool isn't damaged, and the jaw wasn't marked. The motors run cold because the error controls the motor current. They WILL GET to where they are told to go, or they will STOP LCNC in its tracks midstep before the part is damaged. FWIW, that sort of a stop has yet to happen while its working.
I have a 6040 gantry mill, and the Z was too puny even after I binned the electronics that came with it and replaced it all with LCNC feeding 2m542's running on 42 volts. It's xy went from 15 ipm to 200 ipm but z could just barely lift that water cooled spindle, but a 1NM stepper/servo acts like it could lift another 25 pounds at 30 ipm.
When I needed a B axis to make the vise screw I'm going to sell if I can, I made several printed harmonic drives but could not get the speed to spin the screw while I carved it. I had bought a 5/1 worm on spec 4 or 5 years ago, so I put a 3NM on it with a printed shaft adapter, and printed the chuck for the slow end of the worm driving a 2x2 hard maple stick about 2 feet long. I can carve a screw at 200 rpm on the screw.
There's more backlash in the cheap worm than motor error but I'm carving a 2 start thread that fits perfectly by carving the 2nd start on its way back to start a new 1st start. The hard maple stick is turning backwards then. 180 degrees out of phase with the fwd motion.
And Ali-Express is getting plumb reasonable on them right now. [snip Leonardo's problem, this isn't really part of that thread.] Cheers, Gene Heskett. -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author, 1940) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/> _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
