Solved To mesh bed level for a print (or not) and if so how?

[m00dawg]

Printer Model

2.4

Extruder Type

Clockwork 2

Cooling Type

Stealthburner

I've read over the mesh bed leveling instructions a few times and it sounds like it's really only meant to be used as a guide and QGL is all I need? Specifically this bit:

However, it can still be used as an analysis tool to check assembly and see if there’s anything obviously incorrect–just don’t run SAVE_CONFIG at the end of your BED_MESH_CALIBRATE, and run BED_MESH_CLEAR after running bed mesh.

When I generated a mesh in Octoprint I was getting a downward slope. This was before I re-tentioned my belts so I'll give it another go again to check. But I was surprised to read the above. Seems like I would want to use every tool at my disposal for a good first layer?

Question then is, am I misinterpreting this and do folks use mesh bed leveling after QGL as part of the print start gcode? If so, given it says it should clear the bed, I wasn't sure exactly what gcode to put in.

EDIT: I should add, sorry for asking a lot of questions! In part I think it's because not as many folks have moved over from Reddit or FB yet? Hope to see more chatter and banter around here soon! Nonetheless, hope I'm not asking too many questions all at once.

 

[Oberon]

I don't think there are any statistics / poll and there are for sure people who don't run bed mesh leveling before every print, but I would guess most do.

Thing is if you print always in the exact same conditions (temp, soaking time, filament, etc...) you can sometimes get away with doing a bed mesh in these conditions and store that for use when starting every print.

Or if you have a small printer (V0) and a flat enough bed there might be no need for a mesh to begin with.

It's that being said, bed mesh leveling is free insurance and you should use it. Now the "it takes too long" as argument isn't valid anymore because you can use adaptive mesh leveling (KAMP).

Meshing before every prints ensure any mechanical change is taken into account, like a small chip or dust particle that found its way in between the flex plate and the bed's magnet sheet. It also allows to swap plates without worrying about discrepancies between them.

 

[Christian]

I use a stored mesh as default, works great so far. Just make sure you don't have a mesh loaded when you are doing the QGL. I wrote a custom macro the clears the mesh, does the QGL and then reload the mesh. Haven't upadted the mesh in the last two weeks and the Z-Offset is still constant every day.

BED_MESH_CLEAR
M106 S255
QUAD_GANTRY_LEVEL
M106 S0
BED_MESH_PROFILE LOAD=default


My experience was, that the most important part was to make sure that the bed is fixed at the one screw xD

 

[m00dawg]

Thanks folks! Ok sounds like I should look at enabling that. Good to know about the clear before adaptive. That makes me think, if I wanted to do this every time, as part of the print start so something like this:

[gcode_macro G32]
gcode:
    SAVE_GCODE_STATE NAME=STATE_G32
    G90
    G28
    QUAD_GANTRY_LEVEL
    G28
    BED_MESH_CLEAR
    BED_MESH_CALIBRATE
    G0 X175 Y175 Z30 F3600
    RESTORE_GCODE_STATE NAME=STATE_G32

#   Use PRINT_START for the slicer starting script - please customise for your slicer of choice
[gcode_macro PRINT_START]
gcode:
    G32                            ; home all axes
    G90                            ; absolute positioning
    G1 Z20 F3000                   ; move nozzle away from bed

I'll have to look at the adaptive plugin because that sounds absolutely fantastic!

 

[garrettwp]

FYI, you may want to add the bed mesh / adaptive bed mesh to your print start and not your G32, just in case you want to run G32 to Home the printer and not call the bed mesh in the process.

 

[m00dawg]

FYI, you may want to add the bed mesh / adaptive bed mesh to your print start and not your G32, just in case you want to run G32 to Home the printer and not call the bed mesh in the process.

Good point!

 

[m00dawg]

Ok so tested bed flatness by printing small squares at various points on the built plate and yep it's pretty good so I'm gonna go ahead and leave MBL enabled. Doesn't take that much longer to start a print compared to how long QGL takes. Thanks for the help folks!

 

[m00dawg]

Long gap in updates, but been running with MBL for quite some time. But I started realizing it doesn't always give me expected results and am finding that my bed is actually rather flat which makes me think when it's _not_ something else might be going on.

I need to do more testing (such as at temperature) but I think I'm going to rely on QGL for normal operation and just fire off an MBL when I think something might be awry. I saw that because, once I do a QGL, running an MBL and visualizing the results shows an exceptionally flat mesh.

I'm still on the old world OMROM bed probe so other folks may have different results, but I think I'm gonna try it this way and see what comes of it.

 

[Sandman50]

BED_MESH_CLEAR
M106 S255
QUAD_GANTRY_LEVEL
M106 S0
BED_MESH_PROFILE LOAD=default

Yes, this is what I do as well. Works great. (need to do another G28 after the QGL as that may have shifted after the gantry is leveled. The bed mesh just doesn't change given that it's a fixed part of the bed.

If I do something like take the bed off for access to bed fans, then yes, I need to re-mesh the bed.