For context I own 4 mk3s printers and one I have recently converted to Mk3,5s with 0.6mm nozzle after putting roughly 1500hours on it. I am finding using the first layer calibration tool gives good results but when you go to print a part at say 0.32mm layer height 0.2mm first layer, the first layer is way off and I have to adjust z offset to get a good first layer again. I also have to slow it down to roughly 50% speed. once I have a good first layer I can crank the speed back up to 100% and get a good part. 

It appears like the first layer tool doesn't apply z offset appropriately depending on what layer height you print at. same issue for PLA OR PETG smooth or textured bed. No improvement with dried filament and printer in tent. Tried clean beds (soapy water) or with glue stick no difference. 

Slicer 2.9.4

Firmware 6.5.3

https://www.printables.com/model/163547-first-layer-calibration

The only thing is that you must go into the slicer and set the INFIL ANGLE to 90 degrees before slicing, so it does not fill the outline diagonally. I change my Live Z value every half-block.

Posted by: @96toyotacamry-2

I'm new here so, help me understand, to lower more I have to go from -1.390 to -1.490? something like that not -1.390 to -1.290
Correct? 

Posted by: @neophyl

Not low enough, nowhere near enough squish on the first layer.  Adjust your live z a lot lower.

 

Correct! To get more squish, lower from -1.390 to -1.490, not -1.290. That’ll improve your first layer adhesion.

I posted the MMU3 questions here if you want to follow as well: https://forum.prusa3d.com/forum/original-prusa-i3-mmu3-general-discussion-announcements-and-releases/mmu3-mk3-5s-a-great-reliable-experience-or-mk4s-takes-the-throne/

Elephants Foot compensation is located under Print Settings>Advanced>Slicing>Elephants Foot compensation.  Its a yellow setting so you need to be in Advanced or expert mode to see it listed.  Printing a simple rectangle that's 1mm or more high should be enough is enough to see that and adjust it so its not a problem.  Basically anything with vertical sides.

The Brim Separation gap is also a yellow setting.   Located in Print Settings>Skirt and Brim>Brim.  Just below Brim width.

The search bar is amazingly useful for finding a setting if you don't know where it is.  It took many years for the search function to be implemented and its one of those often overlooked things that isn't flashy but oh so handy.  Works surprisingly well.

Once you have a first layer you are happy with you are likely to have a small lip around items you print.  This is known as an 'elephants foot'.  The slicer has a setting to counteract this where perimeters on the first layer are shrunk.  Once the live z is set you can then tune the elephants foot setting to remove the lip. 

Only once that stage is done do you then adjust for a brim.  That has a setting called 'brim separation gap'.  That is used to move the brim outwards slightly, weakening its attachment.  So you want that attached so it can do its job but not too attached.

Could you please guide me to the right place to customize it? 

Thank you

Posted by: @neophyl

First I'd stop trying to dial your first layer in with as benchy.  A waste of filament but also time.  As all we are interested in is the first layer then an object that is a single layer high is all that is needed.  Something like our very own foxruns strip is more than enough https://www.printables.com/model/105404-calibration-strip-for-simple-live-zfirst-layer-cal  

You really need to examine the top and with a single layer object you adjust as its printing requires less passes and far less time.  When you peel it up after its cooled down, you bend the thin sheet produced and if the lines stay solidly together they are squished enough, if they break apart you need lower.  You can also see any drag marks/waves in the top surface that indicate you have gone too low.

Once you have a first layer you are happy with you are likely to have a small lip around items you print.  This is known as an 'elephants foot'.  The slicer has a setting to counteract this where perimeters on the first layer are shrunk.  Once the live z is set you can then tune the elephants foot setting to remove the lip. 

Only once that stage is done do you then adjust for a brim.  That has a setting called 'brim separation gap'.  That is used to move the brim outwards slightly, weakening its attachment.  So you want that attached so it can do its job but not too attached.

Your point about having to redo this every time you swap sheets, then no.  The Mk3 firmware has 'slots' where you can store the live z values of several different sheets.  So you do this for each sheet you have and then store the values in the different slots.  You then can select the appropriate slot when changing the sheet over and your saved value is recalled.  So basically once per sheet. 

Also with the right single layer model and a bit of practice its becomes quick and easy to do this anyway if you do for some reason need to. 

You are correct that with the mk4 you shouldn't need to, but there have been some reports that the first layers are not always as good, due to a variety of factors.  I've even seen posts on here where some users wished they hadn't updated as the first layer was more reliable on the Mk3 (once its set properly)

On the MK4S, so the first layer is not 100% fool proof? that then scares me, because when something is automated, you just expect it to work. But I guess even people using that Bambu X1C with all those sensors, and LidAR stuff also complain about sometimes the first layer not being perfect. Maybe the Core One will address that? 

What do you think about the MMU3 and a MK3.5S together? People, in this forum, are complaining about the filament sensor not being reliable and some issues with different filaments and the first layer. Do you have any experience with MMU3? or multi-color printing ? I don´t plan to print anything crazy, but at least 3-4 color models (with white, orange, black and gray. like this model: https://www.printables.com/model/866524-lid-for-prusa-mk35-rugged-tool-box#preview.file.IjuCa  

You really need to examine the top and with a single layer object you adjust as its printing requires less passes and far less time.  When you peel it up after its cooled down, you bend the thin sheet produced and if the lines stay solidly together they are squished enough, if they break apart you need lower.  You can also see any drag marks/waves in the top surface that indicate you have gone too low.

Once you have a first layer you are happy with you are likely to have a small lip around items you print.  This is known as an 'elephants foot'.  The slicer has a setting to counteract this where perimeters on the first layer are shrunk.  Once the live z is set you can then tune the elephants foot setting to remove the lip. 

Only once that stage is done do you then adjust for a brim.  That has a setting called 'brim separation gap'.  That is used to move the brim outwards slightly, weakening its attachment.  So you want that attached so it can do its job but not too attached.

Your point about having to redo this every time you swap sheets, then no.  The Mk3 firmware has 'slots' where you can store the live z values of several different sheets.  So you do this for each sheet you have and then store the values in the different slots.  You then can select the appropriate slot when changing the sheet over and your saved value is recalled.  So basically once per sheet. 

Also with the right single layer model and a bit of practice its becomes quick and easy to do this anyway if you do for some reason need to. 

You are correct that with the mk4 you shouldn't need to, but there have been some reports that the first layers are not always as good, due to a variety of factors.  I've even seen posts on here where some users wished they hadn't updated as the first layer was more reliable on the Mk3 (once its set properly)