Mk3 when calibrating on pronter the bed is level but when printing it is not
 
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Mk3 when calibrating on pronter the bed is level but when printing it is not  

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Thai Bui
(@thai-bui)
Member
Mk3 when calibrating on pronter the bed is level but when printing it is not

Hi guys i have had this issue for 6 months now and have not been able to finish a single and wasted 3 kg trying to fix this. So when i test the bed level on pronter face it comes out level with in 0.05 but while printing i think the bed varieties a couple millimeters. thanks in advance. please i though buying a prusa would fix my problems from my anet a8 but it has only made more.

Posted : 22/03/2019 6:41 am
Bunny Science
(@bunny-science)
Noble Member
Re: Mk3 when calibrating on pronter the bed is level but when printing it is not

Going to cover basics first, especially if coming from a different printer.
All the following should be a YES

1. Prusa XYZ calibration was completed via the wizard.
2. You have the correct printer profile selected in Slic3r (PE)
3. Filament profile selected in Slic3r matches your spool
4. Your object was sliced using Slic3r

Posted : 22/03/2019 4:45 pm
Thai Bui
(@thai-bui)
Member
Topic starter answered:
Re: Mk3 when calibrating on pronter the bed is level but when printing it is not

yes i use slicer all default settings maybe a little slower speed.

Posted : 22/03/2019 10:06 pm
Thai Bui
(@thai-bui)
Member
Topic starter answered:
Re: Mk3 when calibrating on pronter the bed is level but when printing it is not

This is just a quick example of the bed failing as the print came off mid way

Posted : 23/03/2019 2:07 am
Bunny Science
(@bunny-science)
Noble Member
Re: Mk3 when calibrating on pronter the bed is level but when printing it is not

The usual suspects for parts popping loose I'm thinking you already know coming from another printer...

- Print plate is absolutely clean (washed with Dawn, rinsed clean, paper towel dried, no touching of anything but edges)
- Live Z has been calibrated to make 1st layer perfect

More specific to the Prusa printer build that you might not already be aware...

Print bed and plate will change shape as it heats up. This can be exacerbated by badly distributed stresses created while bolting down the heat bed to y-carriage. This might cause bed shape to change enough that calibration and mesh at lower temp mismatches bed shape while at temperature more than usual.

I would take off the metal sheet, heat bed to 80C, loosen all 9 heat bed screws and retighten them with the bed heated. Use the Prusa recommended tightening pattern (center, left, right, rear, front, left rear, front right, left front, rear right) to gradually tension evenly.

Once that is done, repeat the XY calibration and live Z calibration.

This should get you more consistent bed leveling. The machine normally does a pretty good job with mesh leveling even using default 3 x 3 meshbed. Only when are using a large print area would I worry about needing higher order mesh leveling.

If prints are still popping off after all this, I would concentrate again on cleaning the plate and proper live Z adjustment.

Posted : 23/03/2019 11:45 am
Thai Bui
(@thai-bui)
Member
Topic starter answered:
Re: Mk3 when calibrating on pronter the bed is level but when printing it is not

when i did that the bed still came out uneven

Posted : 24/03/2019 12:12 pm
Bunny Science
(@bunny-science)
Noble Member
Re: Mk3 when calibrating on pronter the bed is level but when printing it is not

If that is the case, then I think there is a build accuracy issue that has XYZ out of square, parallel and planar. So much so , that even bed mesh cannot correct for the amount of build error.

Rather than rewriting everything, I'm going to refer you to my process for refining build accuracy. You may not want to do the entire process, but at least use the alignment tests in that thread to find where you geometry is going wrong.

https://shop.prusa3d.com/forum/assembly-and-first-prints-troubleshooting-f62/planar-parallel-and-square-t26978.html#p125346

Posted : 24/03/2019 6:35 pm
Thai Bui
(@thai-bui)
Member
Topic starter answered:
Re: Mk3 when calibrating on pronter the bed is level but when printing it is not

i just wanna know should i change back from this mod.

Posted : 25/03/2019 12:12 pm
Bunny Science
(@bunny-science)
Noble Member
Re: Mk3 when calibrating on pronter the bed is level but when printing it is not

A nylock bed modification. Good grief! You didn't think that "little" detail was important enough to mention?

You should be at a user level that doesn't need to ask about getting the bed stable and level if you are doing that type of mod. With a nylock mod, you can put the bed completely out of plane unless you do the entire adjustment and checking process with the bed at printing temperature. I have no idea how assiduously you kept the temp correct. Every time you did mesh measurement during the adjustment processs, you had to make sure bed is at the same temp. Otherwise, you guarantee it will be warped at print temperature by "leveling."

You also did it with same print plate as the one you are printing with right?

I think most of your bed leveling issues are self induced.

Posted : 25/03/2019 2:02 pm
Thai Bui
(@thai-bui)
Member
Topic starter answered:
Re: Mk3 when calibrating on pronter the bed is level but when printing it is not

Yes same bed i will change back to normal

Posted : 26/03/2019 2:54 am
Thai Bui
(@thai-bui)
Member
Topic starter answered:
Re: Mk3 when calibrating on pronter the bed is level but when printing it is not

are these xyz calibration numbers good and if not which planar, parallel should i do to fix it.

Posted : 26/03/2019 10:20 am
Bunny Science
(@bunny-science)
Noble Member
Re: Mk3 when calibrating on pronter the bed is level but when printing it is not

It is acceptable, but not great. Ideally, you get it close enough that printer reports the axes as perpendicular. When they are perpendicular, the printer stops adding numerical geometry corrections.

I would check the optical occulations for x and y.

Posted : 26/03/2019 4:58 pm
Thai Bui
(@thai-bui)
Member
Topic starter answered:
Re: Mk3 when calibrating on pronter the bed is level but when printing it is not

would you think this is an acceptable mod.
https://www.thingiverse.com/thing:3109613

Posted : 27/03/2019 11:13 am
Knickohr
(@knickohr)
Member Moderator
Re: Mk3 when calibrating on pronter the bed is level but when printing it is not

Please keep in mind, the shown values are not really exact. There is more or less an error.

In my opinion, all values below 0.1° skew is OK and there is nothing to do.

Thomas

Posted : 27/03/2019 11:48 am
Thai Bui
(@thai-bui)
Member
Topic starter answered:
Re: Mk3 when calibrating on pronter the bed is level but when printing it is not

This is just my pronterface level how could i make it level not have a huge divot on the bottom right corner

Posted : 30/03/2019 9:22 am
Thai Bui
(@thai-bui)
Member
Topic starter answered:
Re: Mk3 when calibrating on pronter the bed is level but when printing it is not

This is just my pronterface level how could i make it level not have a huge divot on the bottom right corner

Posted : 30/03/2019 9:22 am
Thai Bui
(@thai-bui)
Member
Topic starter answered:
Re: Mk3 when calibrating on pronter the bed is level but when printing it is not

0.02283 0.01694 0.01550 0.01850 0.02594 0.03783 0.05417
0.02848 0.03158 0.03332 0.03369 0.03268 0.03031 0.02657
0.03793 0.03908 0.03693 0.03146 0.02268 0.01059 -0.00481
0.05117 0.03944 0.02633 0.01183 -0.00406 -0.02133 -0.04000
0.06820 0.03266 0.00153 -0.02520 -0.04753 -0.06546 -0.07898
0.08904 0.01874 -0.03748 -0.07965 -0.10775 -0.12179 -0.12176
0.11367 -0.00231 -0.09070 -0.15150 -0.18470 -0.19031 -0.16833

Posted : 30/03/2019 9:22 am
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(@)
Illustrious Member
Re: Mk3 when calibrating on pronter the bed is level but when printing it is not

My bed has twice as much deviation and works very well as is; I think my last test was in the 0.45 or 0.5 mm range. A 0.2 range is not causing you issues.

Posted : 30/03/2019 1:20 pm
Thai Bui
(@thai-bui)
Member
Topic starter answered:
Re: Mk3 when calibrating on pronter the bed is level but when printing it is not

then what could i do because the bottom corner that is low on the pronter calibration is the corner that is failing in my prints.

Posted : 30/03/2019 2:10 pm
randolph.l
(@randolph-l)
Honorable Member
Re: Mk3 when calibrating on pronter the bed is level but when printing it is not

Prusa Control and by extension Pronterface are not actively supported by prusa and Prusa Control has been announced as deprecated.

Why do you not use the Slic3r-PE where Prusa puts much of its development efforts right now?

Posted : 30/03/2019 2:32 pm
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