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First layer calibration  

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Mik
 Mik
(@mik-2)
Eminent Member
First layer calibration

As a new user and having just built my MK3s+ im trying to get the first layer right. One thing im unsure about, is the manual lowering of the pinda after first layer calibration. If I think it is too high and lower it, do I need to take off the steel sheet, unload the filament etc and do the XYZ calibration again with tbe paper? Which I assume means starting the calibration Wizard again - or do I just run the Z calibration, before I do the first layer calibration again and leave the steel sheet and filament in place.? 

Best Answer by JoanTabb:

the pinda is a very odd beast, 
it senses the proximity of the steel core of the build plate, or the copper tracks of the heatbed, depending upon which part of calibration you are
doing at the time. 

assuming you do the initial Pinda adjustment with a cable tie, and complete XYZ calibration, then complete Z calibration, successfullt, the PINDA will bring the print nozzle close to the build plate, but not close enough, 
you then need to do First layer calibration... most people use the Prusa First Layer Calibration tool on the LCD menu...  I actually find that difficult to get good results with, and I use the "Life Adjust 'Z' My Way" process....  
https://forum.prusaprinters.org/forum/original-prusa-i3-mk3s-mk3-assembly-and-first-prints-troubleshooting/life-adjust-z-my-way/
which I find more easy to observe the quality of the print and adjust to perfection... 

IF you find that Live Z ends up close to -2.000 mm, then your pinda probably needs re adjusting... 
so first of all re adjust Live Z back towards 0.00mm then loosen your pinda probe clamp and move the Pinda UP, one click (One thread) the Pitch of the Pinda thread is 1.0mm per turn so this should reduce the gap between the nozzle and the build plate by one millimetre. 
tighten the Pinda clamp and re run Live 'Z' adjustment

the odd thing about the Pinda, is that you raise the pinda to reduce the gap between the nozzle and the build Plate....   lowering the Pinda will increase the gap between the nozzle and the build plate. 

If XYZ calibration passes, you should not need to repeat it, unless you change the printer geometry... 

Z calibration needs to be done occasionally in case the X axis gets out of balance on the two Z lead screws... 

Live Z needs doing if you change the extruder assembly in any way, New nozzle, new heatbreak, cleaning nozzle by dissassembly etc. 
AND when changing build plates or sometimes print fialments... the powder coated build plates are thinner than the smooth stickered build plates, and therefore need a lower Live Z value.

Are you using 7x7 mesh bed levelling? this tests 49 positions on the build plate instead of the normal 9 positions

regards Joan

Posted : 19/12/2020 10:50 am
JoanTabb
(@joantabb)
Moderator
RE: First layer calibration

the pinda is a very odd beast, 
it senses the proximity of the steel core of the build plate, or the copper tracks of the heatbed, depending upon which part of calibration you are
doing at the time. 

assuming you do the initial Pinda adjustment with a cable tie, and complete XYZ calibration, then complete Z calibration, successfullt, the PINDA will bring the print nozzle close to the build plate, but not close enough, 
you then need to do First layer calibration... most people use the Prusa First Layer Calibration tool on the LCD menu...  I actually find that difficult to get good results with, and I use the "Life Adjust 'Z' My Way" process....  
https://forum.prusaprinters.org/forum/original-prusa-i3-mk3s-mk3-assembly-and-first-prints-troubleshooting/life-adjust-z-my-way/
which I find more easy to observe the quality of the print and adjust to perfection... 

IF you find that Live Z ends up close to -2.000 mm, then your pinda probably needs re adjusting... 
so first of all re adjust Live Z back towards 0.00mm then loosen your pinda probe clamp and move the Pinda UP, one click (One thread) the Pitch of the Pinda thread is 1.0mm per turn so this should reduce the gap between the nozzle and the build plate by one millimetre. 
tighten the Pinda clamp and re run Live 'Z' adjustment

the odd thing about the Pinda, is that you raise the pinda to reduce the gap between the nozzle and the build Plate....   lowering the Pinda will increase the gap between the nozzle and the build plate. 

If XYZ calibration passes, you should not need to repeat it, unless you change the printer geometry... 

Z calibration needs to be done occasionally in case the X axis gets out of balance on the two Z lead screws... 

Live Z needs doing if you change the extruder assembly in any way, New nozzle, new heatbreak, cleaning nozzle by dissassembly etc. 
AND when changing build plates or sometimes print fialments... the powder coated build plates are thinner than the smooth stickered build plates, and therefore need a lower Live Z value.

Are you using 7x7 mesh bed levelling? this tests 49 positions on the build plate instead of the normal 9 positions

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...
Posted : 19/12/2020 3:02 pm
Mouse and Mik liked
GKMAKEIT
(@gkmakeit)
Estimable Member
RE: First layer calibration

This might help.

https://rumble.com/vb9fxr-3d-printer-first-layer-calibration-process.html

 

Posted : 20/12/2020 12:38 am
Mik liked
Mik
 Mik
(@mik-2)
Eminent Member
Topic starter answered:
RE: First layer calibration

@joantabb

Thanks for the comprehensive guide, ill use the alternative live Z adjust tool you've recommended. In relation to the mesh bed leveling, i've just been using the default 3 x 3, I wasn't aware that there was an alternative - I'll now go into  settings and change it to 7 x 7. I've also just realised that I haven't checked to make sure that my firmware is up-to-date, so I'll check  that before I do anything else.

Posted : 20/12/2020 10:51 pm
Mik
 Mik
(@mik-2)
Eminent Member
Topic starter answered:
RE: First layer calibration

@gkmakeit

Great video, now I know what I'm aiming for.

Posted : 20/12/2020 10:52 pm
JoanTabb
(@joantabb)
Moderator
RE: First layer calibration

@mik-2

Hi Mik, have you checked your slicer is up to date? 

Prusa slicer 2.2.0 is the latest full release, 

2.3.0 RC1 is the current release candidate for new features. I am using this

 

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...
Posted : 20/12/2020 11:57 pm
Mik
 Mik
(@mik-2)
Eminent Member
Topic starter answered:
RE: First layer calibration

Joan

 

Thank you again for your help. I did have the latest firmware. I changed the bed leveling to 7 x 7, as you suggested, and used the "Life Adjust 'Z' My Way" process - and it definitely makes a difference.  I had to lower the pinda again by one thread - and again followed your instructions. It still took me a long time to get the first layer right, as I wasn't sure how far to go. Anyway, I ended up going down to -1.400 and got, what I considered to be,  a good result, which allowed me to successfully print off the Prusa logo. I'm now, partway through printing the whistle. I did have to wash the steel plate quite a few times as well, with washing up liquid/water, to get the filament to stick all the way through the print. 

Posted : 22/12/2020 10:44 am
JoanTabb
(@joantabb)
Moderator
RE: First layer calibration

Good result  Mik,

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...
Posted : 22/12/2020 12:25 pm
Mouse
(@mouse)
Active Member
RE: First layer calibration

Thank you so much @joantabb.  I update my firmware earlier this week and literately spent the last two days (16hrs) trying to get my first layer calibration to work.  The build in calibration is just awful.

I was able to dial in my prints after about two sessions with the "my way" gcode and ran a few extra just for good measure and got a successful benchy on my first post calibration test.

Thanks for remembering this post and re-sharing.

 

Posted : 23/12/2020 5:49 pm
JoanTabb
(@joantabb)
Moderator
RE: First layer calibration

@mouse

it's getting a bit long in the tooth, but it still works, I have similar files for the Mini... 

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...
Posted : 23/12/2020 8:54 pm
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