RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
welp. Looks like I got a bum motor; the VFAs are now on X after my motor swap. It does feel a little grittier than the other one, but not appreciably so.
Guess I'll return it and see what I get in exchange...
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
Did a factory reset - clear all. Ran the wizard, XYZ calibration and height calibration, still reads as ?.
Have some prints to do so reverting to one I compiled on Wednedsay...
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
I think it would also be worth backing off the bear x-cover screws about 1/8 turn. That can be critical especially if one has a stiffer plastic or slightly high extrusion multiplier when printing the x-carriage.
I use Prusa movement speeds or a bit slower in my profiles. I'd pay attention to the non-print move speed as well.
Restoring the default limits in Slic3r for stealth and thereby print slower did the trick.
Now I'd like to fine tune the homing reliability. Above Z 50 or so homing isn't very reliable. What helps is to push the cables a bit to the right (standing in front of the printer) and give the motor some resistance when it hits the endstop.
I think you mentioned somewhere in this thread that it can happen at the very top of Z. At the very bottom it is reliable 99% of the time but already at Z 50 the failure rate is quite high.
At what values should I look to test and fine tune homing?
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
Before you adjust things in the firmware, take some time and vary your x-belt tension. There is a definite range of belt tension that the system likes. If you go too tight or loose, homing becomes unreliable.
Also, be very certain that your x-axis hits are only hard plastic vs plastic. If any portion of cable or wiring touches first, it softens the touch and renders homing unreliable. Pay attention to how the extruder cable bundle touches anything differently as Z-goes up. Also, the noctua and extruder motor wires as they round the left side of extruder can sometimes protrude out of their groove slightly.
Only after exhaustively doing the above checks, should you consider changing parameters in the firmware. The best place to start is reducing x-homing velocity by 200 to 300, but if your printer build is optimized, you typically do not need to tune the parameters.
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
This is so weird.
From the beginning.
Cables are fine and I just recently rewired everything because I changed my hotend fan. I wouldn't want to change my belt tension (or only if everything else would not work) because the printing results are spot on.
So I changed HOMING_FEEDRATE_X 2000 to 1800. Flashed the printer. Went to Z 180 and started homing. No success.
I changed the value back to 2000, reflashed and then I wanted to lower the belt tension a tiny bit (though I wouldn't want to do so fear of losing print quality). I then started homing again and homing works even at the very top without touching the belt tensioner.
Right now I have no explanation for that. I hope it stays reliable but I still would like to know why the result changed though it is the same firmware.
Skelestruder, Slice Thermistor and Magnum support added
VintagePC submitted a pull for Skelestruder support. Skelestruder support is only in MK3 variant.
I have also added support for Slice Engineering thermistor table and increased MMU2 filament load/unload distance (extra 7 mm) if Slice Magnum is specified.
As usual, all the important defines are in configuration_Prusa.h
//====== Kuo Uncommented def(s) below specify 0.9 degree stepper motors on x, y, z, e axis
//Motors used should be 1 amp or lower current rating to avoid overheating TMC2130 drivers in Stealthchop.
//Kuo recommended 0.9 degree motors for X, Y, or direct drive E are Moons MS17HA2P4100 or OMC 17HM15-0904S
//
#define X_AXIS_MOTOR_09 //kuo exper X axis
#define Y_AXIS_MOTOR_09 //kuo exper Y axis
//#define Z_AXIS_MOTOR_09 //kuo exper Z axis
//#define E_AXIS_MOTOR_09 //kuo exper EXTRUDER
//====== Kuo Uncomment ONLY ONE or NONE of below for geared extruders
//Don't forget to also send gcode to set e-steps as detailed earlier
//Reversion back from geared extruder requires sending M92 E280 & M500 to printer
//
//#define SKELESTRUDER // Uncomment if you have a skelestruder. Applies the patches for load distances and Z height.
//#define BMG_EXTRUDER //Kuo Uncomment for BMG 3:1 extruder. This also sets BMG height for you.
//#define EXTRUDER_GEARRATIO_30 //Kuo Uncomment for extruder with gear ratio 3.0.
//#define EXTRUDER_GEARRATIO_3375 //Kuo Uncomment for extruder with gear ratio 3.375 like 54:16 BNBSX.
//#define EXTRUDER_GEARRATIO_35 //Kuo Uncomment for extruder with gear ratio 3.5 like 56:16 Bunny and Bear Short Ears or Skelestruder.
//====== Kuo Slice Support
//#define SLICETHERMISTOR //uncomment for Slice Thermistor
//#define SLICEMAGNUM //uncomment to increase MMU2S filament laod/unload distances for Slice Magnum
//====== Kuo End of defines one normally needs to change ======
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
^^ Note the "load distances" referred to for the skelestruder changes are only for LCD unload and filament load, not the MMU. I'll submit those when I get my MMU working (probably be a few weeks 'till I get to that...)
If you need skelestruder offerings for the 3S then the additional defines are easy to move to the 3S configuration - all of the other changes are in common files.
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
Swapped the iffy motor today, new one is much improved; But it's a fair assumption that we are really setting quite a high bar for motor performance here 🙂
Now to chase down those 2mm vertical bands that correspond to pulley artefacts...
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
I mentioned before, homing issues solved itself after 2 reflashes.
What I did not mention was that I'm using a merged FW between the newest LA 1.5 Release by vertigo235 (he sourced it from wavexx) and the Kuo 0.9 FW. The vertigo release was the base and I copied the 0.9 code into it.
This worked quite well for some days. All of a sudden I had a big layer shift on the y axis yesterday. I then resliced the object and tried to print it again which resulted in a printer that prints in the air. Something was totally wrong. Homing also wouldn't work anymore.
Selftest = loose pulley on Y. I then unscrewed the motor and double and tripple checked everything. Y was sometimes fine than the selftest showed a loose pulley on the X axis and Y axis. That firmware somehow got corrupted or something.
Next I flashed the "stock" Kuo 0.9 firmware and did a hard reset. Selftest passed, homing works again. Started the print and again a layer shift on the y axis. I then swapped the motor on the y axis to the stock 1.8 motor and had no issues (did a reflash for that and a hard reset). I then switched back to the OMC 0.9 motor (and "stock" Kuo 0.9 LA 1.5 firmware) and could reproduce the shift on the y axis. It happens on about the same Z level, but not exactly the same.
For the next test I lowered the tension on the Y axis and as I'm writing this post the next layer shift happened.
What is odd that this shift always happens at about the same Z position. I can print a XYZ cube without issues but this very model gets the y axis to shift layers.
Where should I look next?
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
I had some print weirdness too the other day. Two of my prints refused to start. It did some initial pre-heating and homing, then moved to a mid-position and stopped. Went to cancel and restart and found from the menu they had paused themselves. Hit resume and the prints completed, though the second one decided to randomly conclude it had added about 50 days worth of print time to the stat counter and had been running for hundreds of hours.
(Yes, I'd done a complete wipe after flashing the firmware)
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
I found the culprit for the layer shift. I made a mistake whilst designing the part and didn't think of the filament curling up at this angle and temperature (0.6 nozzle + 0.3 layer height + fast printing speed = high temp needed)
But what stays a mystery is why all of a sudden the printer acts strange and only a reflash + full reset did help then.
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
It did some initial pre-heating and homing, then moved to a mid-position and stopped.
Were you by chance using a gcode file that was sliced with one of my print profiles? My custom startup code includes that initial behavior. It homes, and then moves print head to near mid-bed and leaves it there while preheating the bed/PINDA. Then after a while it starts mesh calibration. One more pause as hotend heats to print temperature. Finally, actual printing begins. If you aren't familiar with that startup sequence, it looks like the print stopped before it began (due to the heating phases).
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
I'm using Bobstro's profiles that do the same thing, so I'm familiar with it. Printer was at temperature (215/60) when it happened so the pre-heating was done. I've done other prints sliced with the same profiles without this issue.
It was a "hard" pause requiring manual resume, not a "waiting for something" pause like a temperature setpoint.
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
What are the speeds like with 0.9° steppers? Particularly the OMC ones. Can they still run 200mm/s? If not, what's their max speed? Thanks!
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
because guy changes the microstep count the motors should work just like the regular ones
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
I think so - though I think he did have to alter the acceleration/power profiles a bit to avoid skipping steps. Prior to changing firmware my Y-axis would skip steps when stopping after a fast travel move.
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
I think he did have to alter the acceleration/power profiles a bit to avoid skipping steps
Actually I never changed speeds to avoid skipping. The only skipping I ever ran into was with running the y-axis without the reduce microstepping. That was overrunning the EINSY CPU. Once I change the firmware to halve the microstepping on X & Y, that issue went away. (Don't confuse that with the more recent change of microstepping for E)
My infill speeds were at 200 mm/sec and working without skipping. In more recent print profiles I have dropped that speed, but it was to get better layer fusion during infill. It wasn't to do anything with skipping.
My normal non-print move speeds are 180 mm/sec.
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
I think he did have to alter the acceleration/power profiles a bit to avoid skipping steps
Actually I never changed speeds to avoid skipping. The only skipping I ever ran into was with running the y-axis without the reduce microstepping. That was overrunning the EINSY CPU. Once I change the firmware to halve the microstepping on X & Y, that issue went away. (Don't confuse that with the more recent change of microstepping for E)
My infill speeds were at 200 mm/sec and working without skipping. In more recent print profiles I have dropped that speed, but it was to get better layer fusion during infill. It wasn't to do anything with skipping.
My normal non-print move speeds are 180 mm/sec.
Interesting, I could have sworn my mesh leveling and post-purge travel moves had slowed down from stock. Your firmware doesn't default to silent mode, does it? My printer was quiet enough I was normally running it in power mode.
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
No. Firmware does not change between stealth or spread cycle. Print does default to spread cycle after a full reset, but that is independent of my firmware.
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
Weird. Must be imagining things then. *shrug