Bilinear Mesh bed levelling


#1

Who is using the Bilinear bed levelling in Marlin 1.1? How many samples are you taking? What sensor are you using?

I am using an inductive sensor, and am currently doing a 55 grid on my 400400 build area, I am considering sampling a lot more prints - maybe 8*8 or more?? I suppose the only thing I have to loose is a tiny bit of time at the start of a print.


#2

I’m using a 10mm capacitive sensor with a 3x3 grid. Works fine, but I did realize the unheated bed vs heated bed make a huge difference with the capacitive sensor. I got a 2mm inductive sensor in the mail to replace it.

I think there’s a way to store the grid somehow so we don’t have to re-calibrate every time the printed goes offline, but haven’t looked much into it.


#3

I was trying to find the info on this as well… last night I found this http://marlinfw.org/docs/features/auto_bed_leveling.html

With RC8 are you guys homing Z in the front left corner 0,0 or have you changed it to the center of the plate like older versions had?


#4

With RC it still homes at the center of the plate. Then the bed leveling starts at front left and moves in rows back to the back (mine finishes right, but I guess that depends on sample points).


#5

Are you sure 2mm will be enough? I have a ‘4mm’ sensor and my z-offset is currently -1.04, heat, voltage, the fact that it is alu not steel all impact the trigger distance.


#6

Weird, I have the latest RC8 December I think and it homes to 0,0 then G29 moves to the first sample point. I thought I had to change something to make it home in the center.

@Squid hey can you send me your config h so I can compare.


#7

I’ll send it tonight, but I don’t think I did anything to change the position.

I’ll also do a pull/merge of the latest into my repo… but I’d imagine I got mine mid-Jan, so after you.


#8

Hopefully… it will work… I’ve got a 5mm aluminium plate.

I do believe I’ll have to move it quite low (almost touching the bed), but shouldn’t impact the prints.
If it fails, I’ll probe the 4 screw in the corners or something.


#9

I was thinking of ordering an 8mm one, just so I have plenty of room to spare, but I wonder if they are as repeatable?


#10

Thats what got me thinking I should change my capacitive sensor :


#11

I saw that, I couldn’t remember the 2 vs 4 vs 8mm inductive results.

my repeatability is awesome with the 4mm - now that I am thinking about it - if it aint broke, don’t fix it!


#12

#13

That’s weird… you actually don’t have any bed leveling enabled by that script?


#14

Dammit, I did a pull from marlin repo and blotted my changes! Lucky you noticed!
:slight_smile:

Look at the history of that file, I’ll revert the changes tomorrow.


#15

Cool and this might be wrong… prob 350 not 3500

#define BACK_PROBE_BED_POSITION 3500