Octoprint says flat, but bed isn't - right side much too low
Hi all, having a strange issue with my mini.
mods:
SuperPinda (mine is old and came with a minda)
Silicon tube bed level mod https://github.com/bbbenji/PMSBLM
Hardened Steel 0.4 nozzle
Squishworx x-axis carriage with cooling duct
Squishworx x-axis end cap
So my printer was working wonderfully, but the petg x-carriage with cooling duct I'd printedand was using was worrying me, as it seemed to be possibly a little melty. So, I ordered https://squishworx.com/prusa-mini-integrated-optimized-cfd-fan-duct-x-carriage/ and installed it. That seemed to go fine, but afterward, I couldn't get the bed level. I tried so much that somehow the x-axis belt got screwed up and split, and the PETG end cap I'd printed was deforming. I've now replaced those, but the bed level problem remains.
I have the SuperPinda as I mentioned, and it's getting a signal. It's returning values. using the silicon bed leveling mod github/website and octoprint I've gotten it to what those report as level, or within 0.03 mm. Now, previously, I'd get it to 0.02 mm and it would stay that way. Currently, every time I run a mesh bed level sequence it gives slightly different results, different screws appearing to need adjustment, even though you just did the exact opposite movement on the previous round.
See pictures for octoprint and raw values from the silicon tube site.
Oh and while trying to fix this I also removed the silicon tube mod entirely and put the original standoffs back. Still wasn't level.
The picture sucks cause my phone can't do that small (or I don't know the setting) but what's happening is the right, near the z tower is too low, while the left is higher. no matter what I set the z-offset to I can't get the right to stick and be squished down, even if the left side is scrapping. It's like there's a magnet screwing with the induction readings or something, like how a compass messes up with magnets.
I'm at my wit's end. Any help is appreciated.
RE: Octoprint says flat, but bed isn't - right side much too low
Did you follow the Squaring Your Miniarticle after replacing the X-axis stuff? That is the first part of the silicon mod instructions, but perhaps you didn't go back to that step after rebuilding the X-axis? The mesh bed leveling only can adjust within a certain range, the printer needs to be square enough first.
Also, have you ever tried running multiple mesh-bed levelings back-to-back without trying to adjust things in between? If so, what are the variations between runs?
I tried so much that somehow the x-axis belt got screwed up and split, and the PETG end cap I'd printed was deforming.
This sounds like perhaps you may have severely overtightened the belt. Did you ever print a belt tension gauge?
RE: Octoprint says flat, but bed isn't - right side much too low
It is quite common to see posts blaming Octoprint for everything between Brexit and the malaise of western society. In this case Octoprint simply displays the data you sent it.
RE: Octoprint says flat, but bed isn't - right side much too low
Ok, so.
No, I haven't printed the belt tension gauge, yet. Not PETG on hand and almost exclusively print PLA so... At the moment the tension is "the end cap was loose, I pulled it to the end with my hand, let go and tightened it down." Obviously not ideal.
As far as I can tell with the tools I have, yea, it's square. May not have been yesterday, but I just did it again so I'm pretty sure it is now.
I have done multiple bed-level checks without adjustments, but I have not made note of the changes. Obvious idea, should have. Will before posting this reply...
I actually gave up on octoprint and tried getting it level "manually," as in a mitutoyo machinist's rule used to check for straightness between the center (which I've never unscrewed) and the other screws. It's ... mixed results. See pic.
Obviously horrifically low in places, but center is actually too high. Here's the raw valus, 3 seperate tests:
I also reflashed the firmware (it's on latest, nothing custom) and checked the electronics box. Everything is plugged in and snug. I haven't done a factory reset but I don't know why that would help.
I am thinking the probe is bad, and giving bad readings. which isn't likely, cause why would it be? So, it's gotta be the software (octoprint) is set up really wrong... I realized that changed too. I had an older install on my windows PC I'd used previously, but it wasn't up-to-date and wasn't working, the server that is. So I went about trying to fix that and found an all-in-one installer for windows and used that. THAT is when the problems with getting level started, which happened to be the same time I was swapping the x-carriage. But I have no idea what settings to mess with, and I've tried sorts of things in the bed-level visualizer plug-in. Flip axis, rotate, center as origin, relative values, use prusa... all of it. yet here we are, with the above pic and bed-level results.
ARGH.
RE: Octoprint says flat, but bed isn't - right side much too low
ARGH.
I feel you. When I first put my mini together I had bed level issues. Check out what I got in back-to-back mesh leveling:
ttyACM0 17°> G29
SENDING:G29
Home XYZ First
ttyACM0 17°> G28
SENDING:G28
endstops hit: Z:1.50
ttyACM0 17°> G29
SENDING:G29
Bilinear Leveling Grid:
0 1 2 3
0 +0.160 +0.195 +0.440 +0.538
1 +0.292 +0.575 +0.817 +0.957
2 +0.463 +0.697 +0.815 +0.993
3 +0.516 +0.798 +1.098 +1.321
ttyACM0 17°> G28
SENDING:G28
endstops hit: Z:1.49
ttyACM0 17°> G29
SENDING:G29
Bilinear Leveling Grid:
0 1 2 3
0 +0.169 +0.207 +0.456 +0.583
1 +0.178 +0.349 +0.590 +0.727
2 +0.106 +0.360 +0.582 +0.760
3 +0.182 +0.491 +0.820 +1.015
ttyACM0 17°> G28
SENDING:G28
ttyACM0 17°> G29
SENDING:G29
Bilinear Leveling Grid:
0 1 2 3
0 -0.505 -0.434 -0.143 -0.010
1 -0.374 -0.251 -0.008 +0.133
2 -0.411 -0.154 +0.070 +0.246
3 -0.380 -0.103 +0.192 +0.418
ttyACM0 17°>
Look at, for example, point 3, 3. +1.321 the first time, +1.015 the second, and +0.418 the third. Unfortunately I never had a very satisfying "this is why" solution. I was 100% convinced the SuperPINDA was bad. Prusa Support tech suggested a Factory Reset followed by re-flashing the firmware. I did that, and did 5 mesh bed levelings in a row, with maximum ~0.1 mm deviation overall. Did my first good 1st layer calibration, and a print, and it was good.
Then I turned it off for the night, turned it on the next morning, and the nozzle was high! I checked more mesh bed leveling outputs, and they were inconsistent. Finally I power cycled the printer and the mesh bed readings were more consistent. Re-did first layer calibration and....it's been fine since. WTF!? Like an entire month, with the printer being used at least 5 days a week. WHY? Like I'm happy it's working, but really frustrated that it glitched out that once after the re-flash, and then just worked flawlessly since.
Other things I did during the process was squaring it. My XZ axis needed correction. It was definitely higher on one side than the other. I used a (old) credit card as a shim for this, moving the Z-axis down until sliding the card under the nozzle, on top of the build plate, there was just a slight amount of friction. Then slide the X-axis over and try the shim again. If it didn't fit or there was no friction, adjust as needed and re-check.
Idea for you to try: So when posting my own mesh bed leveling data, I realized something. The MINI does a 16 point measurement. Your Octoprint results only show 9 points. Either Octoprint is only probing 9 points, or they are taking the 16 points and re-calculating down to 9 (idk why they would do that). Can you try running G29 commands manually?
I have no experience with Octoprint, I've never used it. I read you can send manual G-code commands via Octoprint. Otherwise, you can use Pronterface and/or Pronsole to do this. My understanding is if you are running Windows, Pronterface will be installed when you install PrusaSlicer. Connect your computer to the printer via the printer's microUSB port, and use Pronterface to send the G29 commands. You'll need to send G28 (home) immediately before each G29 (mesh bed leveling) command. G29 has the printer do the 16 point mesh-bed leveling. Once finished, the results will be returned to the program that sent the command, as seen in my mesh bed leveling results above from Pronsole (I'm running Linux, and there was a Linux bug that prevented Pronterface from running, so I had to use Pronsole).
RE: Octoprint says flat, but bed isn't - right side much too low
the raw values I posted are converted from the 16 pointsto 9, to match the mini's screws. This is done via https://bbbenji.github.io/PMSBLM/ which is built to aid in using the silicon tube mod, https://github.com/bbbenji/PMSBLM
Your story is both confusing, terrifying, and hopeful. Heh.
I did the same squaring technique, using the machinist rule on its side as the shim.
Here's some raw data from g29:
Recv: 0 1 2 3 Recv: 0 -0.103 -0.153 +0.046 +0.113 Recv: 1 -0.134 -0.183 +0.018 -0.137 Recv: 2 -0.132 -0.287 -0.069 -0.184 Recv: 3 -0.114 -0.241 -0.001 -0.036 Recv: 0 1 2 3 Recv: 0 -0.123 -0.154 +0.052 +0.102 Recv: 1 -0.152 -0.217 +0.076 -0.126 Recv: 2 -0.111 -0.267 -0.110 -0.166 Recv: 3 -0.096 -0.260 +0.003 +0.001 Recv: 0 1 2 3 Recv: 0 -0.074 -0.087 +0.104 +0.197 Recv: 1 -0.101 -0.135 +0.012 -0.073 Recv: 2 -0.053 -0.225 -0.087 -0.116 Recv: 3 -0.039 -0.191 +0.017 +0.038
I'm gonna give it a few tries and power cycles and see how it goes, But it seems like a factory reset is in my future.
RE: Octoprint says flat, but bed isn't - right side much too low
Well, this is interesting.
I did a factory reset and flashed to latest firmware. Selftest started but immediately rebooted and watchdog reset error. huh. Tried again. Same. Ok... reverted to 4.3.4 firmware, same thing.
huh.
Reading about the watchdog error, I notice the article mentions an operating temperature of 16 to 18 c, or 64 F. well, it's about 67 f in here, and... the nozzle and bed temp readouts on the screen are reporting 23 and 24 c. When absolutely cold. Cold to the touch, even.
Which reminds me, for a few weeks or more I'd been having unexplained underextrusion. This was seemingly fixed by uping the print temp from 195 c to 220 c for my polymaker ployterra PLA, exact same spool. Now I'd moved from arizona to seattle so I figured it was just environmental...
But now I think about it, I also have a 3d pen. It burns the filament when set to around 210 and extrudes fine at 195 or 200. Exact same filament, from the same spools. I'm also remembering when 4.4.0 firmware came out the same watchdog error, but I just skipped the self-test and went about my day... everything was working fine.
Well crap.
I'm... gonna message prusa support now.
RE: Octoprint says flat, but bed isn't - right side much too low
Well that... didn't help much, honestly. "square your mini" and "try a different USB drive" was the end result. I've just gotten the USB drive, had to order one. It's formatting to fat32 now. While I was waiting i made a bunch of gcode's for single layer discs, 50mm, 70 mm, 90 mm... etc. Figured I could find the right z height for the center and adjust the screws manually, using the printed disc to gauge the surface.
Strangely, as I adjust and lower the left, since it appears too high, it... well, the bed leveling is now failing, as in the top right probe point the hotend (with a silicon sock on it) hits the little screw thing the build plate aligns against. and it's still too high.
I think my assessment that it was square was wrong... Gonna factory reset and flash the firmware from the new usb stick and ... just... see where we are. Might remove the silicon tubes and go from there to get level? I don't know. I'm very frustrated right now.
RE: Octoprint says flat, but bed isn't - right side much too low
Ok, well, after getting the new USB stick and doing a factory reset and firmware flash, I think I'm good to go again. Doing some surface prints now, but the center 70mm at least is good!
It seems the USB stick was causing issues? This was one of mine, not the prusa supplied one. Either way - It's working. phew.