Can't print due to autoleveling fails

[Bossler 8]

Hi!

So today in the morning I took out a printed part of the UM3. 

Noticed it seems to be that my UM3 does some serious overextruding, since the gaps in the object where too narrow &

this is not due to design.

But since the next thing I wanted to print was not that critical regarding measurements, I loaded PVA into Slot #2 and started the print.

 

The UM3 did the active-leveling thing & got stuck at the front left corner. 

After several retries he gave up and mentioned some "error 22".

I looked after that and learned I should redo a manual leveling.

Which I did and I followed the instructions on the screen to the word.

I even used a 1mm gauge to make sure that really is exact.

 

After that I started the active leveling again.

It again failed with an error message saying

"Difference between detected height of both PrintCores exceeds realistic values".

 

I did retry the manual- and the automatic bed leveling quite a few times today (actually spent 4 hrs already on this),

but the result remains the same.

Sometimes I could finish the automatic leveling but then the automatic leveling before the print failed.

 

Even removed and re-inserted both print cores already, just in case something got stuck.

Only thing I noticed was, that the BB-PrintCore has a slight resistance when pressing together the handle bars, which the AA-Core does not show.

 

Any help available?

 

I quite a bit dissapointed to see this expensive machine fail right after the second print.

 

P.S.:

on the page reg. Err.22 it is mentioned:

"Ensure the build plate is not levelled to loosely. There should be at least 0.5 mm distance between the nozzle and build plate before a probe starts."

 

I do not really understand what is meant by that & how to ensure this. Can somebody explain that to me?

Edited January 26, 2018 by Bossler
correction

[kcel 11]

I had my auto-leveling get out of sync after a few days of printing.  Probably went thru the same amount of fiddling as you did.

 

I'm currently experimenting with having auto-leveling disabled and I just do manual leveling.  

 

If you want to continue with auto-leveling just tighten up the bed a fair amount (so turn knobs to the right).  Basically you want a short distance between the bottom of the glass and the top of the aluminum plate.  If your build plate is too high (i.e. loose) then the printer has nowhere to go for auto-correcting the level.  So just try tightening each knob by a full turn or so and then run the auto levelling again.

 

[Bossler 8]

kcel,

thanks for the tip. So that is what is meant by ""Ensure the build plate is not levelled to loosely. There should be at least 0.5 mm distance between the nozzle and build plate before a probe starts."", right?

 

Actually I did switch off active leveling earlier today and have a print running right now.

It runs with PLA&PVA and the wipe wall looks simply "scheisse" as we say in german;-)

To me it seems there is a problem with the BB-core but can't figure out what it is.

 

Edited January 26, 2018 by Bossler

[kcel 11]

45 minutes ago, Bossler said:

thanks for the tip. So that is what is meant by ""Ensure the build plate is not levelled to loosely. There should be at least 0.5 mm distance between the nozzle and build plate before a probe starts."", right?

 

Essentially.  I believe how it works is that the auto-level moves the build plate up to some arbitrary point and then slowly nudges the build plate up until it detects it.  It must expect to nudge it a certain minimum distance (probably 0.5 mm) or it gets upset.  I'm guessing this tied to the fact that the 2nd print core, when active, protrudes further than the first one so it needs to be able to compensate for both.

 

I think for auto-levelling to work you basically want the bed to be reasonably level and probably somewhere in the middle of it's movement range with respect to the adjustment screws.

 

45 minutes ago, Bossler said:

It runs with PLA&PVA and the wipe wall looks simply "scheisse" as we say in german;-)

 Scheisse is one German word I am very familiar with.  Learned from a friend long ago and use it often.  

 

45 minutes ago, Bossler said:

To me it seems there is a problem with the BB-core but can't figure out what it is.

Not sure what I can offer with the BB-core issue.  One thing comes to mind:  I've been tweaking my bed-level mid print.  One of the nice design aspects of the Ultimaker is the bed levelling knobs are easily accessible during a print.  So when working through my levelling issues I would start a print, watch the skirt/brim  and just keep tweaking the level until I was happy.  I'm just moving the screws 1/8 or 1/4 turn each time and I watch the print until I see what I'm looking for.  Good stick but not too thin.

 

Also, something really stupid I did when I was manual leveling (because I thought I knew what I was doing): On the second phase of levelling when you adjust the z-offset for the second print core it tells you to adjust the build plate using the wheel.  The first few times I leveled I did that last part using the screw at the rear at the build plate rather than the wheel (it is important to read instructions).    Once I realized my mistake things went smoother. So just double check your not as dim as I am.

 

And finally, there is this thread here on the same subject: 

 

 

Edited January 26, 2018 by kcel

[Bossler 8]

kcel - thanks a lot, sound logical.

 

Also, in the other thread, I read about the instructions on the UM3 display might be wrong in the middle of the procedure...

Will try the alternative approach and report back. 

Just need to wait until the current "sc...e"-looking print is finished;-)

[Bossler 8]

kcel - thanks a lot, sound logical.

 

Also, in the other thread, I read about the instructions on the UM3 display might be wrong in the middle of the procedure...

Will try the alternative approach and report back. 

Just need to wait until the current "sc...e"-looking print is finished;-)

---

UPDATE:
kcel, you made my day!

I did screw in the bed screws completely, then loosened them about 3 complete turns again.

Did a manaual bed leveling then and when it said "turn the screw" at the rear position I used the dial wheel to move the bed electronically instead.

Followed the rest of the "on screen" instructions as displayed.

The automatic bed leveling afterwards worked like a charm!

 

Current print seems to run smooth, noise of Z-correction is very little - likely the manual one was not too bad:-)

 

Again, thanks, Kcel!

[kcel 11]

Awesome!  Glad I could help.

[kmanstudios 1,120]

One thing to keep in mind on the active leveling is that you will sometimes get filament drool that puts just enough distance in between the nozzle ip and the plate to create that difference it detects.

 

Most of what I would have added has been covered quite well by @kcel. One thing I do is to manually toggle the #2 Core up and down just to make sure that it is doing its thang properly and always keep an eye on the filament drool. It sometimes happens if you have just manually moved the filament and there is a bit of back pressure still in there or it can happen while the cores heat up and release any back pressure on the filament. Especially after loading new filament. You can also open the fan casing and just make sure the cores are still snug. They can get pulled a bit when you do cold pulls and such.

 

Keep in mind it is always good to redo your manual leveling to reset any drift in the buildplate over time. This can happen if the nozzle is banging into curled up filament, accidentally hitting the buildplate when removing it or pulling on it too hard. Or, just mechanical drift over time.

[gr5 2,265]

On 1/26/2018 at 6:58 AM, Bossler said:

I even used a 1mm gauge to make sure that really is exact.

No need.  Except when I just put my bed back together I skip right over that part.  It's just to make sure that when you actually do the "true" leveling it doesn't hit any of the clips or scratch the glass.

 

Autoleveling is just a bad idea overall.  It's going to result in the bottom cm or so of your part with varying corrections.  So your part will be less accurate than without this feature.  For example if your bed has a .3mm tilt to it, then your final print will have a .3mm tilt on the bottom layer.

 

Add to this that lots of things can confuse the feature (like some filament on the tip of a nozzle that is above the expected melting temp because now you have pla in but the stuff on the tip is higher temp).

 

When UM gets 9 point or higher autoleveling that compensates for curved glass - THEN it will be a useful feature.  For now it only compensates for tilted planes.

[kmanstudios 1,120]

I am not fully in the 'Active leveling is bad' camp. If one is lazy and does not routinely do a manual leveling to compensate for mechanical drift over time (plate getting knocked around on curling plastic, etc.) then it will be bad.

 

It can promote laziness. But that is on the user.

 

I go by this thought process: I manually level the buildplate as close as I can get it. Then active leveling will compensate for any errors after that. But if I do not manually level periodically, then over time the buildplate will drift further and further out of level and then the active leveling will definitely do what @gr5 says.

 

So, manual leveling is a must. Do not get lulled into complacency and let active leveling do everything for you. It will get to the point it is too far out of level for active leveling to compensate. I know this because when I started, I let it get that far out at one point while learning the basics. But I do let it active level just to compensate for my lack of expertise. I have been printing for  a year now, but I must say that some skills are still in refinement.

 

People like @gr5 are masters and I am not. So, knowing how to fudge those leveling techniques, while important and can give you superior results with experience because you can do some really nifty compensation things, I do not feel, myself, that I am solid enough to make those type of adjustments yet. Mostly because I just have not developed that feel of such cool compensating techniques yet.

[Bossler 8]

After being some days into the usage of the UM3 now, I would like to say:

- the documentation plus the menu guidance on the UM3-screen should be updated for manual bed leveling

- listening to the printing, especially at the lower layers, is advisable - if you hear lots of corrections by active leveling, just do a manual leveling right and your all set

 

[Brulti 177]

On 26/01/2018 at 8:02 PM, kcel said:

Also, something really stupid I did when I was manual leveling (because I thought I knew what I was doing): On the second phase of levelling when you adjust the z-offset for the second print core it tells you to adjust the build plate using the wheel.  The first few times I leveled I did that last part using the screw at the rear at the build plate rather than the wheel (it is important to read instructions).    Once I realized my mistake things went smoother. So just double check your not as dim as I am.

 

I do believe that a lot of us might be guilty of falling for that one, perhaps even more for the non-native English speakers among us...