RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
Thank you again for sharing.
After the Bunny carriage is installed I might increase the current a small bit and measure the temperatures. I like having a bit of headroom since my room is air conditioned in summer and the backside (with passive cooling) does not go over 48°C in stealth.
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
I wonder if my crashes are related to a failing power supply. I've also recently been getting prints that either reset or pause the printer right when it starts trying to purge. I still need to update the firmware but got an X crash yesterday for which the stallguard wasn't tweaked. Seems like momentary voltage dips under load could explain all of my symptoms and I've read reports of replaced power supplies resolving fake crash detections.
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
Power supplies are cheap. I got my latest MEAN WELL LRS-350-24 350.4W 24V from Amazon for $31.
Hilariously it is also listed in a two pack for $74
The biggest hassles were waiting for a new bottom cover print and cutting out a larger fan opening.
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
Well, this should be under warranty so if it is the issue I'd be getting a new black one (I got the older silver ones that seem to have numerous such issues)...
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
Power supplies are cheap. I got my latest MEAN WELL LRS-350-24 350.4W 24V from Amazon for $31.
Hilariously it is also listed in a two pack for $74
The biggest hassles were waiting for a new bottom cover print and cutting out a larger fan opening.
I am going to grab one of these eventually, but I must be one of the lucky few with absolutely no power supply issues on the silver power supply. But then again, I have my printer in the basement where it is always cool and low humidity.
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
I recently added an MMU2 so I would't be surprised if it's just the added load pushing it over the edge; it's been reported the ratings are marginal already for the demand. But that's second hand; I'll probably just hit up chat at some point and describe my symptoms and ask for possible causes/advice to troubleshoot than outright request a new supply
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
I just finished setting everything up with 0.9 OMC steppers, compiling the latest firmware and (barely) passing the selftest. Unfortunately I'm having problems with homing. Frequently it'll just keep trying to grind into the endstop instead of detecting it, both on X and Y. The belts are perfectly centered, idlers are running freely, linear bearings are smooth as butter. It has to be a matter of fine-tuning the thresholds, unfortunately 🙁
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
Just finished with chat, apparently there are some known issues.
a) with crash detection in 3.7.2 (Fix coming in 3.8)
b) It's been reported that the printer resets if the MMU2 sensor has no filament when starting a print, e.g. you've bypassed it to print direct in single mode.
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
The reset can happen if you have the MMU2 plugged into the EINSEY board and then run in normal MK3S mode. If you disconnect the MMU2, it does not happen. It also does not happen on MMU2 single filament mode.
At least this has been my experience so far.
MMU2 1.6 RC2 solved a bunch of my load errors.
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
The reset can happen if you have the MMU2 plugged into the EINSEY board and then run in normal MK3S mode. If you disconnect the MMU2, it does not happen. It also does not happen on MMU2 single filament mode.
At least this has been my experience so far.
MMU2 1.6 RC2 solved a bunch of my load errors.
I'll have to give that a spin. I was bypassing it because I had just a hair over 1m of filament left and a part that needed slightly less than that. Having run it through the MMU would have resulted in a runout halfway through the part as a result of the extra distance from the sensor to the nozzle being "lost".
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
Frequently it'll just keep trying to grind into the endstop instead of detecting it, both on X and Y. The belts are perfectly centered
9 out of 10 times. It's the belt tension too high or too low. Yours may be the exception, but everyone starts out thinking that.
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
Frequently it'll just keep trying to grind into the endstop instead of detecting it, both on X and Y. The belts are perfectly centered
9 out of 10 times. It's the belt tension too high or too low. Yours may be the exception, but everyone starts out thinking that.
My belts were indeed a little tight. Loosening them improved the situation somewhat, but didn't fix it (homing now fails in ~40% of all cases instead of ~60%).
Which values should I play with to see if it helps? I have the drivers heatsinked so I'm not afraid to crank up the juice.
It feels like these 0.9° steppers significantly reduced the window within which the TMCs operate well. They've become super sensitive to small environmental factors, whereas with 1.8° steppers they'd just power through everything and still detect stalls well.
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
Humor me. Try powering the printer all the way off.
Restart and try it again. Sometimes that does something that clears up a homing problem.
Belts I tension to about 6 lbs tension, rather than looking at the near meaningless belt slackness numbers in the support menu.
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
Nope, powering off and on did not fix it either 🙁 X works somewhat reliably now, but Y still struggles, regardless of how much belt tension there is.
What do you mean with "6 lbs tension"? How do I measure that?
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
I use a Short Ears x-axis. The x-tensioner is on a separate carrier. I can directly pull the idler end carrier right (away) and feel the belt tension directly before setting the bolts to hold that tension.
On an axis system that does not allow such easy direct measurement, start with the belt slack.
Push down on the middle of the belt run with the end of an allen key while holding the other end of the key. You are using the key as a more sensitive feeler than than your finger tips.
As you push down, you will notice a point at which the resistance to further deflection increases. That is the point where belt slack has been taken up and you begin to stretch the belt. We don't want to actually stretch the belt more than a TINY bit. We just want to take out the slack.
Tighten belt tension while repeatedly feeling for that point and noting how much you are deflecting the belt. Proper belt tension will be when the deflection is 2-3 mm when you feel the change. Go no further than a small fraction (1/4 to 1/8) of a turn tighter.
At that point belt should be a nice base note when you strum it.
Pay zero heed to the support menu "belt" numbers. They qualify as one of Prusa's little white lies.
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
Then I'm fairly sure that the belt is fine. Weirdly the homing problem is different. Instead of grinding into the endstop, it will hit the endstop twice, then slowly move away from it for two seconds before the printer resets.
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
Yes, that is how Y behaves when it fails to home.
Decrease y homing velocity by 200 or increase the y homing threshold by 1.
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
Bah, despite modified build I'm still having Y crashes. Cleaned and relubricated rods, bed moves freely so I'm kind of at a loss.
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
I'm wondering, is there a reason why you opted to reduce microstepping from 32 to 16 for geared extruders? I know that 8-bit CPU has problems keeping up with the 0.9 steppers on motion axes, but no such problems were reported on the extruder, as far as I know. Doesn't this introduce another possible source of artifacts?
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
I'm wondering, is there a reason why you opted to reduce microstepping from 32 to 16 for geared extruders? I know that 8-bit CPU has problems keeping up with the 0.9 steppers on motion axes, but no such problems were reported on the extruder, as far as I know. Doesn't this introduce another possible source of artifacts?
It should not introduce artifacts, provided you also change the gcode update to half the original setting as well.
He did it to reduce the work the stepper needs to do while loading and unloading filament via the MMU2. The MMU2 loves fast speeds. But I could be remembering it wrongly.