Do I complete the bed mesh before/after M671in the "bed" file?

[fcwilt]

Hi,

As @Phaedrux said level first then create the height map.

But remember to set the Z=0 datum (using G30) before creating or loading the height map

Frederick

[mmartin]

@fcwilt are you referring to the z probe trigger height that is saved in the config.g file?

[mmartin]

@Phaedrux when you say "level out the bed" i believe you are referring to a corexy type of printer in which the z axis motors are moving the print bed itself. Does it make any difference that my motors are attached to the x Gantry (ender 3 setup)?

[fcwilt]

@mmartin said in Do I complete the bed mesh before/after M671in the "bed" file?:

@fcwilt are you referring to the z probe trigger height that is saved in the config.g file?

No.

A single G30 uses the Z probe to set the current Z position value such that Z=0 with be at the desired height, such as the nozzle just touching the bed.

https://duet3d.dozuki.com/Wiki/Gcode#Section_G30_Single_Z_Probe

Frederick

[mmartin]

@fcwilt ah ok. I'll make sure its added to my bed.g file.

[fcwilt]

@mmartin said in Do I complete the bed mesh before/after M671in the "bed" file?:

@Phaedrux when you say "level out the bed" i believe you are referring to a corexy type of printer in which the z axis motors are moving the print bed itself. Does it make any difference that my motors are attached to the x Gantry (ender 3 setup)?

Unless you have modified your Ender such that there are multiple steppers that can level the bed you cannot use Auto Bed Leveling (ABL).

ABL probes the bed to determine how out of level it may be and makes adjustments, using the multiple steppers, to make the bed level.

If your bed has adjustments you can make by hand, such as turning thumbscrews, you can use the Manual Bed Leveling Assistant (MBLA).

This probes the bed in much the same way the ABL does but the result is instructions on how to turn the thumbscrews to level the bed.

Frederick

[mmartin]

@fcwilt I have modified my printer with an EZ ABL Pro and dual Z axis steppers in addition to linear rails, mosquito hotend, bmg extruder, and a silicone heatbed.

[fcwilt]

@mmartin said in Do I complete the bed mesh before/after M671in the "bed" file?:

@fcwilt I have modified my printer with an EZ ABL Pro and dual Z axis steppers in addition to linear rails.

Well it looks like the EZ ABL Pro is just a inductive Z probe - which is fine.

But I don't think that dual Z axis steppers on a bed slinger like the Ender 3 is going to allow you to level the bed.

Unless I am completely misunderstanding how your printer is setup. Can you post a picture?

Frederick

[mmartin]

@fcwilt this isn't my printer but it is how my z steppers are setup. Perhaps it would be better to run these motors in series? My goal was to make sure my x gantry was square with the frame. Or if possible, is there a stall detection option similar to the prusa at the top of the z axis?

[fcwilt]

@mmartin said in Do I complete the bed mesh before/after M671in the "bed" file?:

@fcwilt this isn't my printer but it is how my z steppers are setup. Perhaps it would be better to run these motors in series? My goal was to make sure my x gantry was square with the frame. Or if possible, is there a stall detection option similar to the prusa at the top of the z axis?

Thanks.

To square the gantry to the frame would require someway to "probe" the relationship of the gantry to the frame.

Probing the bed would only work if the bed was absolutely square with the frame.

What you could do would be to mount an end stop sensor of some sort on each Z axis. The current v3 firmware allows for this and will adjust the gantry based on the position of the end stop sensors. So if you took the time to carefully position them you could use the firmware to square the gantry when homing it.

---

BTW does the bed have manual adjustment screws for leveling?

Frederick

[mmartin]

@fcwilt I understand, I'll order some endstops for the top of the z axis. What would be the Gcode commands for this?

[fcwilt]

@mmartin said in Do I complete the bed mesh before/after M671in the "bed" file?:

@fcwilt I understand, I'll order some endstops for the top of the z axis. What would be the Gcode commands for this?

Well for my printer with three Z steppers I have this which specifies which outputs are being used for the Z steppers

M584 X0 Y1:2 Z5:6:7 E3;

Then I have this which specifies which inputs are used for the Z end stop sensors and the other bits of information needed

M574 Z1 S1 P"!duex.e2stop + !duex.e3stop + !duex.e4stop" ; configure active-high endstop for low end

Once you have that then simply homing Z would take care of moving the gantry toward the end stop sensors and adjusting the Z steppers as needed so that both end stop sensors had been triggered at the same time.

The commands would be typical homing commands. The following assumes you are homing to Z min rather than Z max.

G91              ; relative moves
G1 H1 Z-999 F600 ; move down "fast" until the end stop sensors are triggered
G1 Z20           ; move up so the end stop sensors are no longer triggered
G1 H1 Z-999 F150 ; move down "slow" until the end  stop sensors are triggered

If I can find my camera I will make a short video showing the "leveling" in action.

Frederick

[mmartin]

@fcwilt Thanks!

[fcwilt]

@mmartin

Here is a very quick and dirty video showing the "coarse" bed leveling using the three Z axis end stop sensors followed by the "fine" bed leveling using the Z probe and the Auto Bed Leveling feature.

Before doing video this I turned off the printer and carefully adjusted the Z axes positions to put the bed grossly out of level.

Homing and Auto Bed Leveling Video

[Phaedrux]

@fcwilt Your video is marked private.

[fcwilt]

@Phaedrux said in Do I complete the bed mesh before/after M671in the "bed" file?:

@fcwilt Your video is marked private.

I don't use YouTube that much.

I was thinking that when I used the "sharable link" that ignored the private setting.

Thanks.

Frederick

[Phaedrux]

I think the other option is unlisted. I haven't used it myself though.

[Phaedrux]

@fcwilt Video works now. Beautifully done.

[fcwilt]

@Phaedrux said in Do I complete the bed mesh before/after M671in the "bed" file?:

@fcwilt Video works now. Beautifully done.

I get a kick out of watching it level the bed using the end stop sensors when it is way out of level, like I set it up to be.

Frederick

[Phaedrux]

@fcwilt Do you have a write up on your build anywhere? A BOM? It's tempting me to redo my DBot once again. I'm fed up with lead screws.