[Solved] Cannot calibrate XYZ because dirty nozzel?  

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David_001
(@david_001)
Active Member

When I assembled my MK3S, the initial XYZ calibration worked and I was able to print the Frog model.  I moved my printer to a sturdier surface and decided to do the XYZ calibration again.  

 
This time I get a "Clean the Nozzle for calibration".  My kit came with a thin needle-like device I assume is for the nozzle.  I used to to clean and i wiped the nozzle - I don't see any debris.

When I started the XYZ calibration, the "Clean the Nozzle for calibration" message again pops up and I guessed that it was a reminder not an instruction so I ignored it.  Calibration failed.

Upon reading the knowledge base on the subject, my exact error message is:

"XYZ calibration failed. Please consult the manual."
= Calibration point was not found at all. 
 
I also factory reset and ran wizard and again it asked to "clean nozzle" (something which was not displayed the first time).
So this message is not just a friendly reminder, but it detects the nozzle to be dirty)
How do you clean the Nozzle (specifically with the needle device that comes with the kit) so I can calibrate XYZ?

I have read the Knowledge Base on calibration failing - does not mention nozzle cleaning.

 
Also it would help immensely if I knew how the system is detecting the nozzle is dirty and giving that message.
 
Posted : 28/10/2020 8:03 pm
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 -2
(@-2)
Illustrious Member

Are you trying to do the calibration with the steel print sheet on the printer?

It is always wise to get more than one opinion... as for trusting Prusa? No way man....
Posted : 28/10/2020 8:05 pm
David_001
(@david_001)
Active Member

Hi - No, the steel print sheet is off.  

The first time I went through this process the nozzle was brand-new, so I didn't get a "Clean Nozzle before calibrating" message.

After I made my first print and decided to calibrate again, now I get the "Clean Nozzle before calibrating" message - so there is a sensor I think that's detecting a dirty nozzle.  I also factory reset the machine - so it has no memory of my first print.  

I cleaned the outside of the nozzle tip and I also threaded the needle that came with the kit all the way into the nozzle and moved it around multiple times while the nozzle was hot.

Have you ever received an "clean nozzle before clibrating" message?

Posted : 28/10/2020 8:27 pm
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 -2
(@-2)
Illustrious Member

The message comes from the printer encountering an obstruction before the PINDA triggers. Check that the PINDA height is 0.8 to 1.2 mm above the nozzle. Manually set the nozzle on the bed, adjust the PINDA to 0.8mm (lower end of range is usually better).

The other possibility is that the printer is not homing properly. When you press the HOME function, the PINDA should be centered in that white circle on the bed.

It is always wise to get more than one opinion... as for trusting Prusa? No way man....
Posted : 28/10/2020 8:44 pm
David_001
(@david_001)
Active Member

I just pressed "Auto Home" - and the PINDA is *definitely* not centered on the White Circle.  Its about 1.5 mm to the right and like 1mm north of center.

What I don't get is how last night all calibrations worked and I printed a frog....but i guess that's neither here nor there.

I moved the PINDA one notch higher - it made zero difference to how auto-home operated.  "auto-home" does not seem to search for the circle...the bed aligns itself below the PINDA and the PINDA just drops straight down. 

And it is still off-center slightly as before.

do you know how auto-home operates?

 

I will do some PINDA debugging - I think there is a setting from the menu that can give me readouts on the PINDA when i manually move the PINDA.  I will try to get the PINDA 0.8 mm 

Posted : 28/10/2020 9:42 pm
David_001
(@david_001)
Active Member

@tim-m30

I did a PINDA test with a metal object and ran the X belt from left to right - PINDA correctly identifies the metal object when its near.

In auto-home, the nozzle is just about paper-height's away from bed - so I think that's good.

In "support" menu, under "belts"....I see X, Y is offset by 1mm and 2mm which is just about the offset of how far PINDA is away from the circle in auto-home.  I hope I can conclude that this offset is being accounted for? So maybe the auto-home not taking PINDA exactly on the circle is not the main issue.

I still get the "Clean Nozzle before Calibration" message.

How would you recommend I go about cleaning the nozzle to the printer's satisfaction?  How is the nozzle sensor detecting that it's dirty?

Posted : 28/10/2020 9:59 pm
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 -2
(@-2)
Illustrious Member

If the PINDA isn't aligned with the dot, you probably have something physically interfering with the HOME crash.  Essentially, the printer bounces the extruder to the far left. When the steppers stall, that is X-HOME. Then it crashes the bed all the way back. That is Y-HOME. Z is set two ways: the extruder is moved to the top and crashes into the upper stops, that sets limit 1; then the extruder is moved down until the PINDA triggers. That becomes Z-HOME.

It then moves out a certain number of steps in X and Y to place the PINDA over that first cal dot.  The calibration process then homes the PINDA in on the dot precisely - then the second dot, third dot, fourth dot. The dots are where there is a metal pad in the circuit board the PINDA can detect.

 

This post was modified 1 month ago by --
It is always wise to get more than one opinion... as for trusting Prusa? No way man....
Posted : 28/10/2020 9:59 pm
David_001 liked
David_001
(@david_001)
Active Member

@tim-m30

Thank you.  This is very insightful.

This may indeed be yet another issue with my printer.  Although it does pass the belt-test - which it didn't before when a wire was in the way or I had another obstruction.

And even without the HOME being perfect, I was still able to print a Frog - so it got past the XYZ calibration as well.

I am beginning to think this issue has nothing to do with a "clean nozzle" - when the crash to on the Z-axis happens (the screw driven axis), thats when this error message appears.  The printer head never comes back down.  It goes up on the Z axis - hits the limit and stops with the error message about a "clean nozzle".

The plastic tops that hold the Z axis together are not as stern as the metal frame, but I don't see them give when the Z-crash happens.

I need some real professional help!

Posted : 29/10/2020 12:18 am
Peter M
(@peter-m-3)
Prominent Member

Clean nozzle at the top is normal.

This does not mean it is dirty, it does mean, check if it is dirty, then the hit button, then the calibration goes on.

 

Clean all rods, to remove dirt, then put oil on rods, this cleaning needs to be done every 2 or 3 rolls.

Then try again to calibrate.

 

If you move the printer, you do not need to do the xyz calibration, the z calibration is enough(with heated bed and nozzle).

This post was modified 1 month ago 2 times by Peter M
Posted : 29/10/2020 1:27 am
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 -2
(@-2)
Illustrious Member

@davidnia1

It's been so long since I ran the basic cal, the first prompt might be just that: A prompt, rather than an error. What happens if you just click through it and press the select button once?

Just reread the step-by-step and sure enough, it is a check, not an error.

https://help.prusa3d.com/en/article/xyz-calibration-mk3-and-mk3s_112351

It is always wise to get more than one opinion... as for trusting Prusa? No way man....
Posted : 29/10/2020 3:08 am
David_001
(@david_001)
Active Member

I have been clicking through it.  And then it does the 4 point "corner circle" finder - and to be honest, it looks like it goes through without any issues.

But after the final circle on the upper left - it just stops with "calibration failed, check manual and fix issue before continuing".

I don't know at what point it failed or for what reason. 

Its a shame I we don't get the error message.  The printer "knows" there was an error - why doesn't it just say what the error was!!?

All of this worked flawlessly yesterday when I made my first test print.  After that, everything has gone to heck.

A quick question:  Are the screws (9 of them) that affix the thermal bed to the frame used at all by the PINDA at any point?

If so, are yours flush with the bed or inset? 

Thanks

 

Posted : 29/10/2020 4:26 am
David_001
(@david_001)
Active Member

@peter-m26

Thanks Peter - what does "2 or 3 rolls" mean?

Posted : 29/10/2020 4:26 am
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 -2
(@-2)
Illustrious Member

The attachment screws are recessed, and not used. 

I'm back to the basic question of is HOME right?  And your answer "I just pressed "Auto Home" - and the PINDA is *definitely* not centered on the White Circle.  Its about 1.5 mm to the right and like 1 mm north of center."

If Auto Home causes the nozzle to contact or even deflect the bare fiberglass bed or print sheet if mounted, the PINDA is too high. Again, the PINDA must be 0.8 mm above the tip of the nozzle. Find something 0.8 to 1.0 mm thick, with the printer off, manually screw the extruder down [turn both Z screws a step at a time] until the nozzle kisses the bed. Loosen the PINDA and set it so the gauge just fits. Tighten the PINDA. At this point it is best to do a reset with full clear of the firmware memory - use the "ALL DATA" option in this faq. 

https://help.prusa3d.com/en/article/factory-reset_2216

If the PINDA fails to find any of the four cal points, it flags the error. And only a few things will cause the error: The physical home is off or something is interfering with X or Y travel. The PINDA is too high - it doesn't detect the embedded cal points. And then esoteric things like plastic gobbed onto the nozzle. 

You may want to dedicate some time to contact Prusa via CHAT. Log into their web store, select the CHAT feature (lower right of the page). You'll need your order or printer serial etc. But these guys seem to be able to chat you through fixing these issues pretty well these days.  But you need to be patient - typical time for them to pick up the chat is 20 to 30 minutes.

 

It is always wise to get more than one opinion... as for trusting Prusa? No way man....
Posted : 29/10/2020 6:04 am
David_001
(@david_001)
Active Member

I really appreciate your time Tim, thanks again.

I did the factory reset...erasing ALL data.

I noticed the bed had the tiniest lag - fixed that.

I noticed I had installed a set of screws backwards on the Z-axis top plastic holder that attaches to frame - fixed that.

Mind you, with all these defects - I was able to print a Frog last night!  Regardless these were fixed.

Now "Auto Home" is centered.

And I do understand that the "clean nozzle" is really a reminder.

But yes, I still get stuck in the same place.  And as you mentioned and as the manual says this means that it is not finding ANY of the calibration points.

I will chat with Prusa for help.

BTW, what are calibration points? Are these different than the circle home markers?

Thanks (if you have a Bitcoin Cash address let me know, I would love to send you something for your time).

Posted : 29/10/2020 6:23 am
David_001
(@david_001)
Active Member

@tim-m30

SOLVED!!!

I was doing a "belt test" ... and it failed for obvious reasons.  The pulley on the Y-axis motor was loose and it was sliding on the motor shaft.

Fixed that...the "belt test" passed.  Then the XYZ calibration passed as well!

Waiting on that Bitcoin Cash address - thanks again!

Posted : 29/10/2020 7:32 am
Peter M
(@peter-m-3)
Prominent Member

@davidnia1

2 or 3 rolls of filament.

After printing 3 rolls, clean of the rails off dirt , put a little , a few drops of oil on the rails.

If you wait for this to long, the bearings will after a longer time get stuck on moving, and you get errors.

Also check for loose bolt, screws, grub screws, loose parts, etc after short use of printer, a few months, then every 6 months check if some parts are loose.

Posted : 29/10/2020 11:04 am
David_001 liked
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 -2
(@-2)
Illustrious Member

Well that was simple.

The key to longevity on the belt drive is a secret assembly technique: FLAT FIRST

Loosen booth set screws until the gear is free to spin. Align and tighten the set screw to the flat of the shaft. Then, tighten the locking set screw on the shaft round. Order is crucial. To remove the gear, loosen the round set screw then the flat set screw. 

And last - those belt tension numbers on the LCD tell you how much friction the axis has, not the belt tension. For example, my X and Y numbers are 300 or so - and my belts are properly tensioned. 

It is always wise to get more than one opinion... as for trusting Prusa? No way man....
Posted : 29/10/2020 12:29 pm
David_001 liked
David_001
(@david_001)
Active Member

@peter-m26

Hahaha, can you tell I am new here?  Thanks a lot Peter, I am learning quite a bit from kind members such as yourself.

Posted : 29/10/2020 2:45 pm
David_001
(@david_001)
Active Member

@tim-m30

I will be sure to checkout those numbers and look at all the parameters in LCD.  Learning a ton - much appreciated.

Posted : 29/10/2020 2:46 pm
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