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Mach4 General Discussion / Re: Back lash comp while jogging
« on: April 27, 2017, 11:13:05 PM »
Hi Mauri.
Yes i understand all of that. The machine has 5mm ball screws, servo are 10,000 pules per revolution, 50800 steps per inch, the machine does move .0001inch no problems just no backlash comp while doing so.
this has been tested with MPG plugged into the interface on the hicon7766, the Modbus mpg, the Mach4 jog screen, and MDI.
I know it always best to remove all the backlash out of the mechanics first. I work on Commercial machines for a living and my poor Novakon is just not in the same class. It has .0009 inch backlash in Y, it had .0015 in it to begin with.
while checking the bearings on the Y axis, the preload got set a little to tight and ruined that set, Replaced them with 7004 P4 ABEC7 from NSK, checked the bearing block and found some bad machining on the bearing bores and corrected that.
that made up for about 6thents of movement. All that can be take out with out machining, scraping, and upgrading ball screw and bearings has been done. So it is at .0009 and is with in spec for Novakon.
Made a new discovery about backlash comp on the Hicon last night. I think it is just a bug in the Firmware and can be corrected
It will comp when moving in thousandths all day long, or so I thought, every now and then it will not apply the comp to the move at all.
Learned this while running a backlash test for repeat ability last night, ninth run of the program it did not return to the same spot, then again on the 12th run of the program.
started watching the diagnostics page while running the program and checking encoder/ step gen. to the first touch and the last touch, when the part was first touched encoder/step gen was 238386 move off the part past zero then back to zero the encoder/step gen was 238343, this is the base with backlash working.
when backlash was skipped by the by the controller both numbers were 238386. It happened several more times 5 out of 21 runs of the program.
I am send the guys at Vital System a email to see what else they need to test. Still not sure if this is a Hicon issue or a Mach4 issue, or a set up issue. But i will add this to the backlash not comping on .0001 moves with the MPG or jog screens
I will report back when I hear something from them.
explanation on steps per unit is great and should be posted saved some where for the less experienced
the hicon will do the math for backlash for you, in this set up when .0009 is entered it rounded it down to .00088??? don't remember off the top of my head did not write it down probably should have. so it will round it up a pulse or down a pulse depending on the move.
I do love the Hicon, this one is set up with encoder feedback and using home switched and index for homing. it is just great you can indicate a part in set the zeros, shut it all down, leave the indicator set up where it is at, Turn it all back on reference it hit the goto zero button, and it is on the money indicator is back at zero.
Yes i understand all of that. The machine has 5mm ball screws, servo are 10,000 pules per revolution, 50800 steps per inch, the machine does move .0001inch no problems just no backlash comp while doing so.
this has been tested with MPG plugged into the interface on the hicon7766, the Modbus mpg, the Mach4 jog screen, and MDI.
I know it always best to remove all the backlash out of the mechanics first. I work on Commercial machines for a living and my poor Novakon is just not in the same class. It has .0009 inch backlash in Y, it had .0015 in it to begin with.
while checking the bearings on the Y axis, the preload got set a little to tight and ruined that set, Replaced them with 7004 P4 ABEC7 from NSK, checked the bearing block and found some bad machining on the bearing bores and corrected that.
that made up for about 6thents of movement. All that can be take out with out machining, scraping, and upgrading ball screw and bearings has been done. So it is at .0009 and is with in spec for Novakon.
Made a new discovery about backlash comp on the Hicon last night. I think it is just a bug in the Firmware and can be corrected
It will comp when moving in thousandths all day long, or so I thought, every now and then it will not apply the comp to the move at all.
Learned this while running a backlash test for repeat ability last night, ninth run of the program it did not return to the same spot, then again on the 12th run of the program.
started watching the diagnostics page while running the program and checking encoder/ step gen. to the first touch and the last touch, when the part was first touched encoder/step gen was 238386 move off the part past zero then back to zero the encoder/step gen was 238343, this is the base with backlash working.
when backlash was skipped by the by the controller both numbers were 238386. It happened several more times 5 out of 21 runs of the program.
I am send the guys at Vital System a email to see what else they need to test. Still not sure if this is a Hicon issue or a Mach4 issue, or a set up issue. But i will add this to the backlash not comping on .0001 moves with the MPG or jog screens
I will report back when I hear something from them.
explanation on steps per unit is great and should be posted saved some where for the less experienced
the hicon will do the math for backlash for you, in this set up when .0009 is entered it rounded it down to .00088??? don't remember off the top of my head did not write it down probably should have. so it will round it up a pulse or down a pulse depending on the move.
I do love the Hicon, this one is set up with encoder feedback and using home switched and index for homing. it is just great you can indicate a part in set the zeros, shut it all down, leave the indicator set up where it is at, Turn it all back on reference it hit the goto zero button, and it is on the money indicator is back at zero.