Help needed… BigBox Dual with DuetWifi

[dc42]

Some suggestions:

• in the homez.g and homeall.g files you are moving the head to X35 Y15 before probing. It would be better to move to the centre of the bed.
• if after that the nozzle is still too low when you start to print, this means that you have configured the probe trigger height too high (Z parameter in the G31 command). Have you measured the trigger height?
• you don't need the deployprobe.g or retractprobe.g file
• configure your slicer to not generate a M117 message after each layer

[StevenL]

Have not had time yet to measure the trigger height… it didnt take the G29 command.
I'll have more time tomorrow night.
I did find that my slc3r in RepetierHost was starting the z height at 0.3... I changed that to 0.85.

I tried a test print... not please with the results... crappy adhesion, head plowing thru the previous layed filament, globs, jerky movement around the brim.

I can't tell if its settings in the DuetWifi .G files or from the RepetierHost/slic3r config files.
I used the SAME ReptierHost and its config files on the same BigBox, but with the RUMBA board. The change I made was the Com port.

thoughts?

[T3P3Tony]

@StevenL:

Have not had time yet to measure the trigger height…

You wont get the Z probing working correctly until you measure your trigger height and put that into config.g:
https://duet3d.com/wiki/Using_mesh_bed_compensation#Checking_the_trigger_height

@StevenL:

it didnt take the G29 command.

How you you mean it did not take the command?

@StevenL:

I did find that my slc3r in RepetierHost was starting the z height at 0.3… I changed that to 0.85.

Your slicer should be setting Z to the correct first layer height (0.3 sounds correct, 0.85 does not)

[StevenL]

OK so I went thru and measured the z probe trigger over 9 points. similar to the areas used by the RUMBA mesh.
What do I do with those values?

I went ahead and defined the mesh grid with: M557 X10:270 Y10:200 S20
BUT i get this error: AFTER a G29 command: Error: Z probe was not triggered during probing move

I tried with bigger spacing of M557 X10:270 Y10:200 S60, but I get the SAME error after G29.

What do I do now?

[T3P3Tony]

Lets start at the beginning, I am assuming that your bed is roughly level left/right and back front, If not its best to adjust mechnically until . When you do a simple G30 in the center of the bed is the new Z height correct (determine by using a paper feeler).

If its not correct then change the Z trigger offset in config.g until it is correct.

[StevenL]

So am I to understand that the DuetWifi only uses 1 point as the overall Z-Height reference for the WHOLE print bed?

IF so, that's not what even the RUMBA can do. In fact one of the selling points of the Mesh bed leveling is to NOT have to level the entire bed. Even e3d shows a video of an extreme tilted bed… raised about an inch or two on the left and the print STILL prints flat, true and level.

Please tell me how to use my manual 9 point test points in a mesh bed format.

[dc42]

Have you read this guide https://forum.e3d-online.com/index.php?threads/my-guide-to-duet-mesh-auto-leveling.2456/ ?

Edit: fixed link

[elmoret]

@StevenL:

So am I to understand that the DuetWifi only uses 1 point as the overall Z-Height reference for the WHOLE print bed?

It can do that, or it can do several positions over the area of the print bed.

But the first step is telling the Duet where the probe is relative to the nozzle's tip. Which is what Tony was trying to help with.

The IR sensor measures the distance from the IR sensor to the bed. But what matters is the distance from the nozzle to the bed. So it is necessary to find that difference, or "offset". Which is what Tony was trying to assist you with.

[Dougal1957]

and you don't need to do manual measure at a number of prob points either also the Mesh bed leveling will work out it's own number of probe points from the params you feed it think it is of the order of 170plus on a cartesian you just need to tell the firmware max and min for each axis and the spacing between the probe points.

But as both Tim and Tony have said the system needs to know at what hight the IR Board triggers at when the nozzle is just touching the bed!

[StevenL]

I keep getting this: Error: Z probe already triggered at start of probing move

I'm thinking that the movements of the Z motors are not measured the same as the command.
How do I calibrate the movements of each of the X, Y and Z motors? Meaning, When I command +5 on the panel or Gcode, the motor actually moves 5mm.
I'm using the stock motors on this BigBox dual.

[dc42]

The amount of Z movement is controlled by the Z parameter in the M92 command in config.g. This sets the steps per mm.

Another possible reason for probing starting too close to the bed is that your Z axis travel from the homing position is a little less than the 250mm you have specified. Set it in the M208 command.

[StevenL]

Update:
My mm steps needed to be 1600. not 400 as was shown in the above config.g file.
I was able to do the mesh leveling macro from that PDF elmoret posted. Thanks
The trigger height was 1.38.
The graph that appears after I ran the macro, does show all red, but that's ok by me as long as the print is fine. I;m not even sure how to improve it. Instructions?
I did two test cubes for the xyz calibration.
They look good, however I can see the differences between the two based upon the slicer changes.
I use Repetier Host 2.0 and Slic3r.

[dc42]

If the height map is all red then that just means that the homed height is not exactly the 250mm that you quoted in the M208 Z parameter. If you want to see what the height map looks like, position the head over the center of the bed and probe there using a single G30 command, before you run G29.