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First Layer Help - Sloped Bed?  

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First Layer Help - Sloped Bed?

I can't understand what I've got going on, so hopefully the attached pic makes it more clear.

When I start the first layer cal (using https://www.printables.com/model/20306-first-layer-calibration), the first third or so prints alright (starts beautifully), but it slowly gets less and less acceptable. It's as if the bed is sloped somehow, but a full re-calibration ran successfully (and told me the bed was good)

Has anyone experienced this kind of first layer issue? It's basically a non-starter for any printing, and I've got no idea how to best fix it. IMG_4259

Best Answer by JoanTabb:

are you using 3x3 mesh bed levelling, or 7x7 mesh bed levelling

Selectable option via mk3 series LCD Menu. 

I always use 7x7, 
and I set it to take notice of magnts, so effectively the printer tests 49 points on the build plate instead of the normal 9 points, then the printer ignores seven of these test points, because they are affected by magnet placement, and it uses the remaining 42 points for mesh bed levelling. 

I suspect that you have a Mk3S+,   the later Mk3S and Mk3s+ printers have a Supa Pinda, 
the Supa pinda is not temperature stabilised. (It's supposed to be much more stable than the previous Pinda Versions... but just for test purposes. lets assume it's not... 

On the Mk2 series printers the early Pinda was also a three wire device, and it was affected by temperature which lead to some issues
many people found that the Pinda gave different responses dependant upon where the pinda was, during initial heating of the print bed...

I found with my  printer that if I did a 'home all axis' and then heated the printer for a new print, I would get a good first layer, but, if I printed a model the extruder would end up, say 60mm above the build plate,  if I now did a new print starting at 60mm instead of just above the build plate, 
My first layer would be rubbish, because the pinda was cooler  and the sensitivity was different. 

Try using home all axis, before your next print,  set 7x7 mesh bed levelling, do a first layer calibration adjust live z as required, (You may need to repeat Home all axis, and calibration print with live Z adjustments a couple of times, when your first layer looks good,  do another home all axis and see if the next first layer calibration test comes out good, without any changes in live Z

regards Joan

Ce sujet a été modifié il y a 2 years par 0x90
Publié : 17/12/2022 4:06 am
JoanTabb
(@joantabb)
Veteran Member Moderator
RE: First Layer Help - Sloped Bed?

are you using 3x3 mesh bed levelling, or 7x7 mesh bed levelling

Selectable option via mk3 series LCD Menu. 

I always use 7x7, 
and I set it to take notice of magnts, so effectively the printer tests 49 points on the build plate instead of the normal 9 points, then the printer ignores seven of these test points, because they are affected by magnet placement, and it uses the remaining 42 points for mesh bed levelling. 

I suspect that you have a Mk3S+,   the later Mk3S and Mk3s+ printers have a Supa Pinda, 
the Supa pinda is not temperature stabilised. (It's supposed to be much more stable than the previous Pinda Versions... but just for test purposes. lets assume it's not... 

On the Mk2 series printers the early Pinda was also a three wire device, and it was affected by temperature which lead to some issues
many people found that the Pinda gave different responses dependant upon where the pinda was, during initial heating of the print bed...

I found with my  printer that if I did a 'home all axis' and then heated the printer for a new print, I would get a good first layer, but, if I printed a model the extruder would end up, say 60mm above the build plate,  if I now did a new print starting at 60mm instead of just above the build plate, 
My first layer would be rubbish, because the pinda was cooler  and the sensitivity was different. 

Try using home all axis, before your next print,  set 7x7 mesh bed levelling, do a first layer calibration adjust live z as required, (You may need to repeat Home all axis, and calibration print with live Z adjustments a couple of times, when your first layer looks good,  do another home all axis and see if the next first layer calibration test comes out good, without any changes in live Z

regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Publié : 17/12/2022 9:03 am
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Topic starter answered:
RE: First Layer Help - Sloped Bed?

Looks like changing to the 7x7 bed leveling fixed the issue! Thank you so much for the suggestion!

Publié : 18/12/2022 6:37 pm
JoanTabb
(@joantabb)
Veteran Member Moderator
RE: First Layer Help - Sloped Bed?

My Pleasure

 

Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Publié : 18/12/2022 7:05 pm
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