have problems with mesh bed leveling

fcwilt

@lui2004

Why are all of the commands in your bed.g commented out?

As to getting G29 to do a simplified 4 point probe try M557 X5:215 Y9:210 P2.

Those values are determined by the values in your bed.g file. In that file you specify the first two points as X215,Y210 and X215,Y9 with the X of the third point as X5. So I am using the X range (5 to 215) and the Y range (9 to 210) to specify the four points of a rectangle which would give you a simplified height map showing just the overall levelness of the bed.

Now I don't recall if the M557 command needs to be set taking into account the probe offset or not.

I don't use the bed leveling assistant as I find it hard to turn the adjustment screws just the amount reported.

I just use G29 with 4 point probing near the corners of the bed. Then I can look at the values reported in the height map and tweak the adjustment screws. It takes a number of runs of G29 but I find that I can get the four points adjusted within 0.005 mm easily and within 0.001 mm with a bit more work.

One I have the bed leveled to my satisfaction then I use G29 with multi-point probing to determine the actual mesh compensation to use during printing.

Frederick

lui2004

i still try it

thanks

lui2004

it seems almost perfect

epRapFirmware height map file v2 generated at 2019-10-03 19:25, min error 0.000, max error 0.017, mean 0.009, deviation 0.008
xmin,xmax,ymin,ymax,radius,xspacing,yspacing,xnum,ynum
5.00,215.00,9.00,210.00,-1.00,210.00,201.00,2,2
  0.017,  0.000
  0.017,  0.002

fcwilt

Hi,

Were you actually running the bed.g file with all of the commands commented out?

Frederick

lui2004

my bed.g is like this:

;; bed.g
; called to perform automatic bed compensation via G32
;
; generated by RepRapFirmware Configuration Tool v2 on Mon Apr 29 2019 10:01:00 GMT+0200 (Mitteleuropäische Sommerzeit)

M561 ; clear any bed transform
G28 ; home
M401 ; deploy Z probe
G30 P0 X215 Y210 Z-99999 ; probe near an adjusting screw
G30 P1 X215 Y9 Z-99999 ; probe near an adjusting screw
G30 P2 X5 Y114 Z-99999 S3 ; probe near an adjusting screw and report adjustments needed
M402 ; retract probe

lui2004

G29 with multi-point probing i got this output

T3P3Tony

If you compare the simple 4 points, with the multi point it certainly looks like your bed has a huge bulge. try rotating the surface or flipping it over to confirm it is a physical issue with the bed surface.

lui2004

ok shit

can you recommend me a good bed ?

lui2004

today i have changed the bed and all is flat

now,what i do first before i start print?
G29 S1 ; Load Mesh
G32 to Level the 2 independend Z-Motors

and the start print is correct ? if yes my prints starts over the air if do this

fcwilt

@lui2004

Well for my DBOT equipped with 3 Z-axis steppers and I am leveling the bed and/or creating the height map as separate operations via Macros

For printing I:

warm the bed and extruder heater for several minutes
home all
set the "Z=0 Datum" using the Z-probe
load the height map
begin print

Frederick

lui2004

for Simplify3d in Endscript is the code like this ?

G28 ; home all axis
G1 X110 Y110 ; Go to Center
G30 ; Z=0 Datum
G29 S1 ; Load Mesh

fcwilt

@lui2004

The only gcode I have in S3D is to use M98 to invoke two macros, print_begin.g and print_end.g

Frederick

lui2004

Hi

i have never used macros, can you explain me ho to use it ?

thanks a lot for your help

grizewald

@lui2004 said in have problems with mesh bed leveling:

Hi

i have never used macros, can you explain me ho to use it ?

thanks a lot for your help

A macro is just a file containing G-codes. You use M98 P"macro filename" to run a macro by name.

They are great for putting the code for a specific function which you might want to run from various places in one file so there's only one file to edit when you need to change things.

For example, you could have the code needed to home your X, Y and Z axes repeated in both homeall.g and the individual home macros. Or, you could just call the individual home macros from homeall.g

lui2004

ok nice !

for example for z=Datum

Zdatum.g

G1 X110 Y110 ; Go to bed center
G30 ; Probe once

and then i can insert in Simplify3d in Startscript

M98 Zdatum.g

is it correct ?

infiniteloop

@lui2004 said in have problems with mesh bed leveling:

is it correct ?

You're very close:

M98 P"Datum.g"

lui2004

yeah i will do my best ,i will learn

infiniteloop

@infiniteloop said in have problems with mesh bed leveling:

You're very close:

... as was I. Let's try it again:

M98 P"Zdatum.g"

Sorry.

fcwilt

@lui2004 said in have problems with mesh bed leveling:

and then i can insert in Simplify3d in Startscript

M98 Zdatum.g

As stated by the other poster your syntax is not quite correct.

But consider the approach of having just two calls in S3D to macros that do everything you need to start printing and to finish printing.

That those macro can call other macros if that makes things easier.

My goal is to minimize changes I have to make in S3D and keep all the changes in the Duet.

Frederick