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Cornmeister
(@cornmeister)
Member
Bed curved ?

Hi All,

Even after a series of calibration, my first layer prints (Prusament PETG) on my Mk3S+ look like this:

Looks like the bed is curved, the center looks a little lower.

Any idea how to solve this ?

Posted : 07/03/2022 9:33 pm
Cornmeister
(@cornmeister)
Member
Topic starter answered:
RE: Bed curved ?

Btw, I've checked if there was anything under the steel sheet. Bed is clean.

Posted : 07/03/2022 9:53 pm
Diem
 Diem
(@diem)
Illustrious Member

Try 7x7 mesh-bed levelling; in the Lcd menu.

Cheerio,

Posted : 07/03/2022 11:48 pm
Cornmeister
(@cornmeister)
Member
Topic starter answered:
RE: Bed curved ?

Tnx Diem, 

I've tried that.

Even with the 7x7 mesh bed levelling, the center part of the prints are looking bad.

 

any suggestions ?

Posted : 08/03/2022 2:57 pm
Cornmeister
(@cornmeister)
Member
Topic starter answered:
RE: Bed curved ?

did some more tests,

tried another sheet, no difference.

When I increase the flow to 110, the center part of the print looks ok, but the corners are ruined.

Posted : 08/03/2022 3:45 pm
Diem
 Diem
(@diem)
Illustrious Member

Is this a recent build?

Did you follow this carefully?

https://help.prusa3d.com/en/guide/7-heatbed-psu-assembly_172872    Step 17

A cautious loosening and retightening may help.

Cheerio,

Posted : 08/03/2022 5:06 pm
Cornmeister
(@cornmeister)
Member
Topic starter answered:
RE: Bed curved ?

I received this printer in January, Fully assembled.
Had to remove the bed because of a support issue. (rattling bed).

I've just loosen and retighten the screws, the prints got a little better, but still a lot of gaps at the center.

 

Posted : 08/03/2022 5:26 pm
Cornmeister
(@cornmeister)
Member
Topic starter answered:
RE: Bed curved ?

After another calibration session, the print improved a lot, but still gaps.
Any advise ?

Posted : 08/03/2022 6:30 pm
ARU
 ARU
(@aru)
Eminent Member
RE: Bed curved ?

Take a look at Chris Railey's advises

Posted : 08/03/2022 7:01 pm
Cornmeister
(@cornmeister)
Member
Topic starter answered:
RE:

I've bought this printer, just to not have to modify it, its not an Ender 🙂

thanks for the advice anyway !!

Posted : 08/03/2022 7:30 pm
Diem
 Diem
(@diem)
Illustrious Member
RE:

Don't try the mods just yet. 

Had to remove the bed

OK, you may have unsettled something.  Your printer had been calibrated but you went deep enough to negate that.

You say you got some improvement and I agree it's slightly better, we seem to be in the right area.

I suggest you redo the loose and retighten, but tighten with the bed as hot as you can work with, 50 degrees or more if you can manage it.  Pay strict attention to the sequence.

Then refer to the setting up a new printer preflight tests and do an XYZ calibration.

https://help.prusa3d.com/en/article/xyz-calibration-mk3-mk3s-mk3s_112351

Followed by mesh-bed levelling and so-on.  Your PINDA should be OK unless you've played with it so leave it where it is.

Cheerio,

 

Posted : 08/03/2022 9:36 pm
Cornmeister
(@cornmeister)
Member
Topic starter answered:
RE: Bed curved ?

Will try tomorrow. Tnx Diem

Posted : 08/03/2022 10:03 pm
Cornmeister
(@cornmeister)
Member
Topic starter answered:
RE: Bed curved ?

@diem Issue is still there 🙁
What can I do next ?

Posted : 09/03/2022 5:47 pm
Diem
 Diem
(@diem)
Illustrious Member
RE:

Slightly better balanced.  What happens if you calibrate the first layer  to get the centre of the bed right?  Do the corners ripple?

Cheerio,

Posted : 09/03/2022 8:08 pm
Cornmeister
(@cornmeister)
Member
Topic starter answered:
RE: Bed curved ?

thats the point, how ? just by lowering the nozzle with live Z offset ?

Posted : 09/03/2022 8:09 pm
Diem
 Diem
(@diem)
Illustrious Member

Yes.

Cheerio,

Posted : 09/03/2022 8:10 pm
Cornmeister
(@cornmeister)
Member
Topic starter answered:
RE: Bed curved ?

I will give it a try tomorrow! tnx again

Posted : 09/03/2022 8:10 pm
Cornmeister
(@cornmeister)
Member
Topic starter answered:
RE: Bed curved ?

Yes, corners look terrible, Rippled and way too low nozzle.

Posted by: @diem

Slightly better balanced.  What happens if you calibrate the first layer  to get the centre of the bed right?  Do the corners ripple?

Cheerio,

 

Posted : 11/03/2022 9:06 am
Lynn
 Lynn
(@lynn)
Estimable Member
RE: Bed curved ?

I suffered with this as well (for over a year) and finally I got tired of not being able to print larger items due to adhesion failures on the periphery of the bed,  I gave in and did the mod described in Chris Railey's video.  I couldn't get it flat enough with the default screws and standoffs and while the mode seems kind of rinky-dink, it works.  You have to be patient when making adjustments and allow the bed to reheat before running the levering app after each adjustment, and unless your crazy lucky you will have to readjust you z-height offset.  For me, it was a mode worth doing as  I now routinely use the entire bed with no problems.

I'm glad I did it.

Posted : 11/03/2022 12:07 pm
Diem
 Diem
(@diem)
Illustrious Member
RE:

OK, a small bodge to complete the point:

Loosen the centre bed screw by a small amount: 1/4 to 1/2 a turn.  Can you get a decent calibration now?

Cheerio,

Posted : 11/03/2022 5:19 pm
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