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klaudijus_95
(@klaudijus_95)
Active Member
Bed not even in all corners

So I have assembled my first Prusa MK3s, however, I can see that my bed is quite uneven, so I wonder what can I do to even it out. I have adjusted z-live calibration, so the bed is not even.

It seems like a lot of confusion about how to fix unevenness for this printer on the forum, one forum topic says that "Bed Level Correction" helps with unevenness, another one says it doesn't really work as supposed...

I have knowledge about FDM printers and how the bed leveling works for the first layer, just not for this printer, so I am open for advice.

This topic was modified 2 years ago 2 times by klaudijus_95
Posted : 21/02/2020 9:55 pm
rmm200
(@rmm200)
Noble Member
RE: Bed not even in all corners

How do you know your bed is uneven? Take the print plate off and check the heat bed with a straight edge?

Do you have any pictures?

 

Posted : 22/02/2020 2:12 am
klaudijus_95
(@klaudijus_95)
Active Member
Topic starter answered:
RE: Bed not even in all corners

Okay so I have 2 issues , one is that layers have different results on different places of the bed. Another one as shown in the picture below, that corners are loose or maybe get dragged up. So I am taking step by step, first trying to figure out why layers have different results on different places of the bed.

I did not use a straight edge, however, I did this :

1. I did print a bed calibration test on corners & edges, some places nozzle was perfect, other places it was either too far or close...

2. I also  ran  G81, that shows you some values on those measurements, picture bellow illustrates the differences

Both X-axis sides hit the top at the same time so I would assume that is not the issue 

Posted : 22/02/2020 12:05 pm
rmm200
(@rmm200)
Noble Member
RE: Bed not even in all corners

Thanks - the pictures will help anyone looking at it.

I would see if cleaning the bed helps the loose corners. A fingerprint in that location could cause that.

Scrub the bed with hot water and unscented dish detergent. Rinse thoroughly and dry with a clean paper towel.

Never let a finger touch the print area.

Now try that print again. No IPA this time.

On those G81 numbers: Are they in MM? Did you tighten the screws in the manual specified order, center screw first? If the lower right is .27mm low, try a thin shim under the plate at that screw? How thick is aluminum foil anyway...

 

Posted : 22/02/2020 3:52 pm
klaudijus_95
(@klaudijus_95)
Active Member
Topic starter answered:
RE: Bed not even in all corners

I have cleaned with IPA, but will definitely try with unscented dish detergent. I managed to improve the corner quality a bit by changing print speed on first layer to 10mm/s, is the spring steel bed that terrible on sticking PLA to the bed? Because on my other printer I have no issue on printing first layer on at least 40mm/s on a glass bed. 

Not sure what "MM" abbreviation stands for. But, yes I followed the instructions on tightening the screws.  I tried a 0.2mm shim but did not end up as a success, that corner ended up too high compared to others, so maybe aluminum foil will do the deal.

 

Posted : 22/02/2020 5:22 pm
rmm200
(@rmm200)
Noble Member
RE: Bed not even in all corners

The picture you show is the smooth PEI sheet. It is fantastic for PLA adhesion - but the least bit of grease will mess it up.

A fingerprint, a bottle of IPA you touch a rag to (always squirt or pour) - these can cause grease contamination.

If you want a PLA challenge - get a textured plate. Fantastic in it's own way, mandatory for PETG - but challenging.

Posted : 22/02/2020 5:48 pm
klaudijus_95
(@klaudijus_95)
Active Member
Topic starter answered:
RE: Bed not even in all corners

Well now I don't know, I have gotten my bed quite even now. This should mean that once live Z is adjusted the whole bed should be level. I always use IPA for grease, but maybe need to change to something else (at least try...).

Yet my layers seem to be perfect some places and other places totally wrecked.

Posted : 22/02/2020 7:24 pm
rmm200
(@rmm200)
Noble Member
RE: Bed not even in all corners

So what did you use to fix the height?

Those numbers look really good.

Posted : 23/02/2020 2:32 am
klaudijus_95
(@klaudijus_95)
Active Member
Topic starter answered:
RE: Bed not even in all corners

I found that I had 4 nylocks in the spare bag from Prusa, I wanted to try if it would work with only 4 of them instead of 8. Seems like it worked, however still struggling with printing, but had some improved progress by increasing bed temperature from 60 to 70 C.

Posted : 23/02/2020 9:33 am
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