Auto leveling problems

Dougal1957

10 factors, 6 for outer circle, 3 for inner circle and one in the middel

Thats not 10 factor it is 10 points What is the S parameter at the end of your last G3 line in your Bed.g File that is the number of factors?

scheffer

I don't see a G3 line in my bed.g file. Here it is:

[c]
; Auto calibration routine for delta printers
; Before running this, you should have set up your zprobe Z offset to suit your build, in the G31 command in config.g.

M561 ; clear any bed transform, otherwise homing may be at the wrong height
G31 X0 Y0 ; don't want any probe offset for this
G28 ; home the printer

;*** Remove the following line if your Z probe does not need to be deployed
;M98 Pdeployprobe.g ; deploy the mechanical Z probe

; The first time the mechanical probe is used after deployment, it gives slightly different results.
; So do an extra dummy probe here. The value stored gets overwritten later. You can remove this if you use an IR probe.
;G30 P0 X0 Y0 Z-99999

; Probe the bed and do 6- or 7-factor auto calibration
G30 P0 X-73.6 Y-42.5 Z-99999 ; X tower
G30 P1 X0 Y-85 Z-99999 ; between X and Y towers
G30 P2 X73.6 Y-42.5 Z-99999 ; Y tower
G30 P3 X73.6 Y20 Z-99999 ; between Y and Z towers
G30 P4 X0 Y67 Z-99999 ; Z tower
G30 P5 X-73.6 Y20 Z-99999 ; between Z and X towers
G30 P6 X-36.8 Y-21.25 Z-99999 ; half way to X tower
G30 P7 X36.8 Y-21.25 Z-99999 ; half way to Y tower
G30 P8 X0 Y42.5 Z-99999 ; half way to Z tower
G30 P9 X0 Y0 Z-99999 S6 ; centre, and auto-calibrate 6 factors

;*** Remove the following line if your Z probe does not need to be retracted
;M98 Pretractprobe.g ; retract the mechanical Z probe

G1 X0 Y0 Z150 F10000 ; get the head out of the way of the bed
;G28
[/c]

scheffer

Thanks Jackal for helping out. My printer is working for a couple of hours more so I will check the values a bit later in the day.

Dougal1957

@scheffer:

I don't see a G3 line in my bed.g file. Here it is:

[c]
; Auto calibration routine for delta printers
; Before running this, you should have set up your zprobe Z offset to suit your build, in the G31 command in config.g.

M561 ; clear any bed transform, otherwise homing may be at the wrong height
G31 X0 Y0 ; don't want any probe offset for this
G28 ; home the printer

;*** Remove the following line if your Z probe does not need to be deployed
;M98 Pdeployprobe.g ; deploy the mechanical Z probe

; The first time the mechanical probe is used after deployment, it gives slightly different results.
; So do an extra dummy probe here. The value stored gets overwritten later. You can remove this if you use an IR probe.
;G30 P0 X0 Y0 Z-99999

; Probe the bed and do 6- or 7-factor auto calibration
G30 P0 X-73.6 Y-42.5 Z-99999 ; X tower
G30 P1 X0 Y-85 Z-99999 ; between X and Y towers
G30 P2 X73.6 Y-42.5 Z-99999 ; Y tower
G30 P3 X73.6 Y20 Z-99999 ; between Y and Z towers
G30 P4 X0 Y67 Z-99999 ; Z tower
G30 P5 X-73.6 Y20 Z-99999 ; between Z and X towers
G30 P6 X-36.8 Y-21.25 Z-99999 ; half way to X tower
G30 P7 X36.8 Y-21.25 Z-99999 ; half way to Y tower
G30 P8 X0 Y42.5 Z-99999 ; half way to Z tower
G30 P9 X0 Y0 Z-99999 S6 ; centre, and auto-calibrate 6 factors

;*** Remove the following line if your Z probe does not need to be retracted
;M98 Pretractprobe.g ; retract the mechanical Z probe

G1 X0 Y0 Z150 F10000 ; get the head out of the way of the bed
;G28
[/c]

Sorry my bad it should have been the last G30 line which I see has S6 at the end of it which is 6 factor Calibration.

I suspect that what you are experiencing is Effector Tilt at different location around the bed.

You may have said what Z Probe you are using but I can't recall it at the moment but if it is a Mini IR Sensor then it will be mounted some way from the nozzle which will mean that the trigger hight will vary as the effector tilts and you can allow for this by using H offset values for each of your probe points

For example each G30 line appart from the Last one can have a H parameter added after the X and Y params to define this hight difference.

HTH

Doug

edit I see you do state in your first post re the mini IR Sensor

scheffer

Thanks Doug!!

Did a couple of auto delta calibration measurements and here are the results:

G32: Calibrated 6 factors using 10 points, deviation before 0.200 after 0.048
M666: Endstop adjustments X-0.15 Y0.32 Z-0.17, tilt X0.00% Y0.00%
G32: Calibrated 6 factors using 10 points, deviation before 0.059 after 0.058
M666: Endstop adjustments X-0.20 Y0.36 Z-0.17, tilt X0.00% Y0.00%
G32: Calibrated 6 factors using 10 points, deviation before 0.054 after 0.053
M666: Endstop adjustments X-0.18 Y0.34 Z-0.16, tilt X0.00% Y0.00%
G32: Calibrated 6 factors using 10 points, deviation before 0.056 after 0.055
M666: Endstop adjustments X-0.17 Y0.34 Z-0.17, tilt X0.00% Y0.00%

I then heated the bed to 60 degrees celcius.
G32: Calibrated 6 factors using 10 points, deviation before 0.079 after 0.050
M666: Endstop adjustments X-0.18 Y0.35 Z-0.18, tilt X0.00% Y0.00%

My manually found corrections from the config.g file are:
M666 X-0.21 Y0.31 Z-0.09

The results seem pretty consistent although the first two were slightly off.

So effector tilt might very well be the problem. How do I measure the H offsets of each of my probe points?

Jackal

You can follow David's instructions here:
https://www.duet3d.com/forum/thread.php?pid=5191#p5191

scheffer

Thanks.
Followed the procedure.
Made three macros. One to go up with 0.02 mm (my printer is 100 steps/mm), one to go down with 0.02mm and one to do the measurement 3 times:

[c]
G92 Z0
G1 Z5
G30 S-1
G1 Z5
G30 S-1
G1 Z5
G30 S-1
[/c]

My measure 10 points:
P0 1.77
P1 1.67
P2 1.85
P3 1.95
P4 1.73
P5 1.7
P6 1.74
P7 1.82
P8 1.86
P9 1.78

P9 is the center coordinate so I used these H adjustments:
[c]
; Probe the bed and do 6- or 7-factor auto calibration
G30 P0 X-73.6 Y-42.5 Z-99999 H-0.01 ; X tower
G30 P1 X0 Y-85 Z-99999 H-0.11 ; between X and Y towers
G30 P2 X73.6 Y-42.5 Z-99999 H0.07 ; Y tower
G30 P3 X73.6 Y20 Z-99999 H0.17 ; between Y and Z towers
G30 P4 X0 Y67 Z-99999 H-0.05 ; Z tower
G30 P5 X-73.6 Y20 Z-99999 H-0.08 ; between Z and X towers
G30 P6 X-36.8 Y-21.25 Z-99999 H-0.04 ; half way to X tower
G30 P7 X36.8 Y-21.25 Z-99999 H0.04 ; half way to Y tower
G30 P8 X0 Y42.5 Z-99999 H0.08 ; half way to Z tower
G30 P9 X0 Y0 Z-99999 S6 ; centre, and auto-calibrate 6 factors
[/c]

Result still not good…

dc42

I assume you execute the macro after jogging the head down so that it just grips a piece of paper. You say the results are not good, but you haven't told us what fhey are.

scheffer

Yes correct. Macro executed after gripping a piece of paper.
Results are not good as the first layer is still not level. My manually inserted three values still perform better. Close to the X tower the nozzle is too close to the bed and close to the Z tower it looks good or maybe slightly too high.

I was quite surprised to see that there is a 0.3mm difference (lowest and highest measurement) due to effector tilt. Is this quite common or do I have a bad build? And are my H offsets correct? I will do another round of measuring tomorrow to make sure I did not make a mistake.

After switching the printer on I homed it and used the commands M561 and G31 X0 Y0 before starting the paper gripping. Not sure if they are necessary?

dc42

I used to have 0.3mm trigger height variation on my delta. it was caused by a combination of play in the joints, a carriage rotated about the Z axis, and a carriage rotated about its face.

Running M561 is necessary if you have used G29 bed compensation. Running G31 X0 Y0 only affects G30 commands that include XY coordinates.

scheffer

Did another two rounds of measuring the H offsets and found some different values. Probably needed some experience in paper gripping to get the right feel to do it consistently for every point.

first new round:
-0.14
-0.13
0.09
0.16
-0.1
-0.2
0.01
0.09
0.07

second new round:
-0.18
-0.16
0.08
0.17
-0.08
-0.18
0.02
0.09
0.1

New H offset values in the bed.g file:
; Probe the bed and do 6- or 7-factor auto calibration
G30 P0 X-73.6 Y-42.5 Z-99999 H-0.16 ; X tower
G30 P1 X0 Y-85 Z-99999 H-0.14 ; between X and Y towers
G30 P2 X73.6 Y-42.5 Z-99999 H0.08 ; Y tower
G30 P3 X73.6 Y20 Z-99999 H0.17 ; between Y and Z towers
G30 P4 X0 Y67 Z-99999 H-0.09 ; Z tower
G30 P5 X-73.6 Y20 Z-99999 H-0.19 ; between Z and X towers
G30 P6 X-36.8 Y-21.25 Z-99999 H0.01 ; half way to X tower
G30 P7 X36.8 Y-21.25 Z-99999 H0.09 ; half way to Y tower
G30 P8 X0 Y42.5 Z-99999 H0.08 ; half way to Z tower
G30 P9 X0 Y0 Z-99999 S6 ; centre, and auto-calibrate 6 factors

Finally managed to get good leveling now.
Thanks for all the help everybody!!