Loading

My printer still wont use my BLTouch leveling

Please Login to Comment

So my BLTouch on my i3 plus runs the leveling sequence fine. both before a print, and if i do it manually through the settings. however, it appears that it doesnt apply those settings to the print. Am i missing something?

Here is my starting gcode

G21 ;metric values
G90 ;absolute positioning
M82 ;set extruder to absolute mode
M107 ;start with the fan off

G92 E0 ; zero extruder
G1 E-1.0 ; prevent oozing while leveling
G92 E0 ;re zero
G28 ;Home

G29 E ; auto bed level

G1 Z15.0 F200 ;move the platform down 15mm
G1 X0 F2800
G1 Y0 F2800
G92 E0 ;zero the extruded length

G1 Y0 F700 ; move out of print volume (negative values dnt work, hits endstop)
G1 Z0.2 F700
G1 X60 E9 F700 ; start purge line
G1 X100 E12.5 F700 ; continue purge line
G1 X120 E22.0 F700 ; continue
G1 X140 E30.0 F700 ; continue extrudes at various speeds to knock off bits
G1 X160 E34.0 F700 ; continue stuck to outside of nozzle from being hot while G29
G1 X180 F800 ;finish line
G1 X190 F1200 ; zoom to pull off bits stuck to nozzle
G1 Z10 F700 ; safty height

G92 E0 ;zero the extruded length again
G1 F{travel_speed}
M117 Printing...\

Edit:
so i did some more testing, and it is doing mesh bed leveling. i confirmed it by raising one side of my bed all the way, and dropping the other side, so it fell by 15-20mm across the bed. and the leveling worked fine and it was able to print. however, regardless of the bed's angle, the lower left corner always prints too close to the bed, and the upper right is too high. so i dont know if it is calculating the mesh wrong or something?

You have to remember that leveling is not a perfect science. It can't really polish a turd. Even on my Prusa's, a variance over 50 microns makes its impossible to fix. On my 12"x12" bed (mk2s clone), the bed is not great but Im lucky that it has no variance outside 25 microns, so my 2mm inductive sensor does a great job. If im reading the data correct you have some very large variances. It could simply be you are outside the spec of what is capable. You might want to double check the frame/ bed level again.

i am printing on glass, so it is all on one plane. the leveling manually doesnt matter, because the mesh bed leveling adjusts the z height as it prints to match the bed. the problem here is that my probe knows the bed is askew, but it is not changing the z height at all, it is behaving like it doesnt have mesh bed leveling.

the BLTouch has a standard deviation of <0.01mm so it should behave way better than being off almost 0.2mm. teaching tech did a video on youtube about the BLTouch and he skewed his bed by shoving a ruler under one side, and the sensor was able to correct for that, so my slight misalignment should be no big deal to fix.

I would still check your frame/bed. Eliminate the dumb stuff first.

from the first picture it looks like it is setting up a grid properly. those values are the measured z values at the various points of the grid it measured.

Yeah, the problem is that it knows that the bed is at an angle, but it doesnt correct for it like it should when printing. so one corner is too close, and the other is much to high up.

what thickness are you printing at. you are compensating for almost .2 mm at the one end. I am assuming that in the photo the rectangle on the left is the -0.026 and the rectangle on the right that isn't fully filled in is the -0.173 side. if that's the case the simple fact that you are getting adhesion on the right hand rectangle means its working. you are compensating for almost .2 mm. it may not be a perfect first layer but with a deviation like that its sticking if ahead of the game. turn off the mesh leveling and then try the print again. I am willing to bet that the right hand rectangle tries to print in the air. you could always up your first layer to .3mm to see if that will help

so i did some more testing, and it is doing mesh bed leveling. i confirmed it by raising one side of my bed all the way, and dropping the other side, so it fell by 15-20mm across the bed. and the leveling worked fine and it was able to print. however, regardless of the bed's angle, the lower left corner always prints too close to the bed, and the upper right is too high. so i dont know if it is calculating the mesh wrong or something?

im printing at .2 and .3mm first layer heights and it does not affect the outcome.

I am going to assume that you are using a 9 point mesh. it could be that something is out of wack on the lower left corner that is not covered by that point that it measures. If it doesn't affect you prints I would just live with it. you can spend a lot of time trying to figure it out for the sake of figuring it out.

the problem is that it does affect my prints. to get the rest of the bed at a reasonable height, that quadrant is printing way too close.

yes 9 point mesh, centered (the default is not centered)

You could always increase the number of mesh points, and or change the location of the points so they take the lower left corner more into account. you may not be able to take the corner fully into account because of the offset on the BLTouch from the hotend, but you can probably get closer.

also you can try to print further from that corner to minimize its effects.