Triple Z Axis G32 Bed Traming

Turricann

@Phaedrux Yes i realized what i had done late as i posted it and removed the H2 on the G1 move you will have to bear with me this is my first attempt @ setting up a 3D printer.

@jay_s_uk
Yes everything is in the correct order triple checked this including M671 and probe points.

@fcwilt you are correct the lead screw points are outside the bed area however the probe points are the position where the bed mount attaches to the bed unless you know of a way to put an offset in for the actual positions ?

@gloomyandy your description fits my bed setup.

@CaLviNx just reading through your config should the M671 command come after M584 not before ?
Referance https://duet3d.dozuki.com/Wiki/Bed_levelling_using_multiple_independent_Z_motors.

; bed.g
; called to perform automatic bed compensation via G32
;

M561 ; clear any bed transform

G28 ; home all

G30 P0 X170 Y30 Z-99999 ; probe near a leadscrew middle right
G30 P2 X-180 Y-170 Z-99999 ; probe near a leadscrew Front left
G30 P1 X-190 Y190 Z-99999 S3 ; probe near a leadscrew rear left and calibrate 3 motors

G1 X0 Y0 F8000
G30 Z

; homez.g
; called to home the Z axis
;
G91 ; relative positioning
G1 H2 Z5 F6000 ; lift Z relative to current position
G90 ; absolute positioning
G1 X0 Y0 F6000 ; go to first probe point
G30 ; use probe to find Z 0
G91 ; relative positioning
G1 Z10 F6000 ; lift Z relative to current position
G90 ; absolute positioning

A Former User

@Turricann said in Triple Z Axis G32 Bed Traming:

@CaLviNx just reading through your config should the M671 command come after M584 not before ?

Which part of my disclaimer did you not understand ?

fcwilt

@Turricann said in Triple Z Axis G32 Bed Traming:

@fcwilt you are correct the lead screw points are outside the bed area however the probe points are the position where the bed mount attaches to the bed unless you know of a way to put an offset in for the actual positions ?

How is it possible to probe at the lead screw locations? How can the probe get to those location without colliding with the lead screws?

The M671 values should be the actual XY position of each leadscrew while the G30 XY positions should be somewhere on the bed.

Frederick

jay_s_uk

@fcwilt or the kinematic mount positions

A Former User

@jay_s_uk said in Triple Z Axis G32 Bed Traming:

@fcwilt or the kinematic mount positions

That's a more accurate explanation

@fcwilt some printers the lead screws only job is to move the axis, and they can also have pivots used to eliminate over constraining that axis

Turricann

@fcwilt I understand what you mean, i had taken it as the M671 command needed to match the commands in the bed.g
ie the probe points but i have now updated the potions to match the actual lead screw position leveling seem to work better now but i need to run the leveling process twice as the first run did not adjust the offset correctly.

output from the console.
G32
Leadscrew adjustments made: 1.999 1.920 3.028, points used 3, (mean, deviation) before (-0.548, 3.417) after (-0.000, 0.000)
Leadscrew adjustments made: 0.057 -0.082 1.163, points used 3, (mean, deviation) before (-2.838, 3.845) after (0.000, 0.000)
1/2/2021, 5:09:05 PM G32
Leadscrew adjustments made: 1.166 1.972 2.849, points used 3, (mean, deviation) before (-0.292, 2.602) after (-0.000, 0.000)
Leadscrew adjustments made: 0.115 -0.163 0.823, points used 3, (mean, deviation) before (-2.285, 3.068) after (0.000, 0.000)

fcwilt

@CaLviNx said in Triple Z Axis G32 Bed Traming:

@jay_s_uk said in Triple Z Axis G32 Bed Traming:

@fcwilt or the kinematic mount positions

That's a more accurate explanation

@fcwilt some printers the lead screws only job is to move the axis, and they can also have pivots used to eliminate over constraining that axis

That was not the point I was trying to make.

My question dealt with how it was possible to probe the lead screw position (or the mount position).

And as we now see the OP misunderstood what the parameters to M671 should have been.

Frederick

fcwilt

@Turricann said in Triple Z Axis G32 Bed Traming:

@fcwilt I understand what you mean, i had taken it as the M671 command needed to match the commands in the bed.g
ie the probe points but i have now updated the potions to match the actual lead screw position leveling seem to work better now but i need to run the leveling process twice as the first run did not adjust the offset correctly.

You still seem to be having a problem. On my printer two runs are always enough to get it spot on.

Does a single G30 to set the Z=0 datum work as expected? If you move to Z=0 is the nozzle touching (or nearly so) the bed?

Frederick

Phaedrux

@Turricann said in Triple Z Axis G32 Bed Traming:

G1 X0 Y0 F6000 ; go to first probe point
G30 ; use probe to find Z 0

The position of the probe for the G30 should match between homez and homeall (and any other place you are setting Z0)

Turricann

@fcwilt

Doing a single G30 probes the bed @X0, Y0(Bed center), Doing a G1 Z0 the nozzle moves so its touching the bed.

Turricann

@Phaedrux I see i had not set the probe offset, however the bed is still not tramming correctly any other thoughts ?

fcwilt

@Turricann said in Triple Z Axis G32 Bed Traming:

@fcwilt

Doing a single G30 probes the bed @X0, Y0(Bed center), Doing a G1 Z0 the nozzle moves so its touching the bed.

Thanks.

Seems like your Z probe is configured and working correctly.

Perhaps the following may help:

I don't do multiple passes in my bed.g - just one. And I also end the bed.g processing with setting the Z=0 datum at the center of the bed.

I obtain multiple passes by ending my homez.g file with two G32 commands.

Frederick

Turricann

@fcwilt

I have changed the M671 leadscrew Positions from where the leadscrews are to the pivot points under the bed as in @CaLviNx config.g example.

The bed leveling now seems more consistant,
1/2/2021, 9:51:43 PM G32
Leadscrew adjustments made: 0.291 0.320 0.311, points used 3, (mean, deviation) before (0.307, 0.010) after (-0.000, 0.000)
1/2/2021, 9:50:43 PM G32
Leadscrew adjustments made: 0.307 0.299 0.307, points used 3, (mean, deviation) before (0.305, 0.004) after (-0.000, 0.000)
1/2/2021, 9:49:43 PM G32
Leadscrew adjustments made: 0.308 0.294 0.297, points used 3, (mean, deviation) before (0.300, 0.005) after (-0.000, 0.000)

fcwilt

@Turricann said in Triple Z Axis G32 Bed Traming:

@fcwilt

I have changed the M671 leadscrew Positions from where the leadscrews are to the pivot points under the bed as in @CaLviNx config.g example.

The bed leveling now seems more consistant,
1/2/2021, 9:51:43 PM G32
Leadscrew adjustments made: 0.291 0.320 0.311, points used 3, (mean, deviation) before (0.307, 0.010) after (-0.000, 0.000)
1/2/2021, 9:50:43 PM G32
Leadscrew adjustments made: 0.307 0.299 0.307, points used 3, (mean, deviation) before (0.305, 0.004) after (-0.000, 0.000)
1/2/2021, 9:49:43 PM G32
Leadscrew adjustments made: 0.308 0.294 0.297, points used 3, (mean, deviation) before (0.300, 0.005) after (-0.000, 0.000)

Did you try adding the G30 in your bed.g file to set the Z=0 datum after the leveling phase?

Your bed seems level but has a Z offset.

Frederick

fcwilt

@Turricann said in Triple Z Axis G32 Bed Traming:

I have changed the M671 leadscrew Positions from where the leadscrews are to the pivot points under the bed as in @CaLviNx config.g example.

@dc42 - is that the correct way to set M671 for printers with kinematic mounts?

Thanks.

Frederick

A Former User

@fcwilt said in Triple Z Axis G32 Bed Traming:

@Turricann said in Triple Z Axis G32 Bed Traming:

I have changed the M671 leadscrew Positions from where the leadscrews are to the pivot points under the bed as in @CaLviNx config.g example.

@dc42 - is that the correct way to set M671 for printers with kinematic mounts?

Thanks.

Frederick

Sigh, this is yet another reason I add a disclaimer....

jay_s_uk

@fcwilt I would've thought gloomyandys answer was sufficient

fcwilt

@jay_s_uk said in Triple Z Axis G32 Bed Traming:

@fcwilt I would've thought gloomyandys answer was sufficient

Why?

dc42 did the code - who knows if these special cases were taken into account or if it even matters.

Even though I have kinetic mounts specifying the position of the leadscrews works fine.

Frederick

Phaedrux

@fcwilt said in Triple Z Axis G32 Bed Traming:

who knows if these special cases were taken into account or if it even matters.

It's an approximation of location at any rate, since you're trying to approach zero, the farther off your estimate is, the longer it takes to reach. It says the position of lead screws, but that's just an assumption that most people will have printers with lead screws and won't have specifically designed pivot points, in which case, the lead screw is the natural pivot point. So technically, M671 is defining the pivot point, but in practice that's most commonly going to be a lead screw, and even more practically, it doesn't matter so much as long as you're "pretty close".

fcwilt

@Phaedrux said in Triple Z Axis G32 Bed Traming:

It's an approximation of location at any rate...

Thanks for the feedback. It is consistent with my experiences.

Frederick