Z wont go to the corect dept when printing.

[Snippy]

This post is deleted!

[droftarts]

@Snippy said in Z wont go to the corect dept when printing.:

From tip to nozzle tip in Z is 2mm

Are you measuring the Z offset of the probe in this position, ie when it is retracted? If so, that's wrong. You need to measure the height of the nozzle when the probe is triggered, ie when the probe pin is deployed, and it comes in contact with the bed, which then retracts. The nozzle will be a couple of mm off the bed, and it is this offset you need to measure. The instructions to mount the BLTouch "2mm above the nozzle" is just to make sure it's far enough away from the nozzle when retracted that it doesn't hit the print, but low enough that when it deploys it is below the nozzle, so touches first.

Follow the instructions to determine the Z height that you posted. If the probe isn't consistent in the number it reports from multiple probing (try running the script here: https://forum.duet3d.com/post/335748)

im starting to think that duet in general is just cursed.

Nope.

Ian

[Snippy]

@droftarts
So this
Checking the trigger height

The Z probe trigger height must not vary significantly with XY position. Measure the trigger height of your Z probe at various XY positions and make sure it is consistent. To measure the trigger height:

Make sure there is no filament stuck to the nozzle (you may want to do this test with the nozzle hot)
Cancel any existing bed compensation by sending M561
Send M564 S0 to allow movement lower than where the firmware thinks Z=0 is. This is to ensure that you can lower the nozzle all the way to the bed in step 5.
Command the print head to the XY coordinates you want to probe. This can be any place where both the nozzle and the probe are over the bed. Either use the jog buttons in DWC, or send a G1 command (eg G1 X100 Y100) to move to a specific location.
Command the print head down in small steps, using the jog buttons in DWC or by sending individual G1 Z[value] commands, until the nozzle just touches the bed or just grips a sheet of paper. You may also wish to create a macro to lower the head by e.g. 0.02mm to get greater accuracy (G91 followed by G1 Z-0.02).
Send G92 Z0 to define that height as Z=0
Command the nozzle up 5mm (G1 Z5)
Send G30 S-1 to probe the bed without resetting the Z=0 position
Read off the Z height from the web interface. That is the trigger height.
Repeat the previous two steps a couple of times to make sure you are getting a consistent result
Repeat steps 4-10 for the other XY positions you want to check.

Does nothing?

[Snippy]

@droftarts
G1 Z-1.97 F50 ; Nozzle Z0 Y200 X160
G92 Z0
G1 Z5
G30 S-1
Stopped at height 4.054 mm

Got G30 S-1
Stopped at height 4.054 mm to give a consistent result.

is 4.054 mm the nozzle height?
; Probes
M558 K0 P9 C"io7.in" H5 F120 T6000 ; configure BLTouch probe via slot #0
G31 P500 X45 Y0 Z4.054 ; set Z probe trigger value, offset and trigger height
M950 S0 C"io7.out" ; create servo #0 for BLtouch
M557 X0:400 Y0:400 S20

???

[droftarts]

@Snippy said in Z wont go to the corect dept when printing.:

is 4.054 mm the nozzle height?

Yes.

G31 P500 X45 Y0 Z4.054 ; set Z probe trigger value, offset and trigger height

Yes, put it in the G31 Z parameter.

Your instructions are missing a couple of steps at the end, where it explains how to put the Z offset in G31. Where did you get them from? Proper instructions here https://docs.duet3d.com/en/User_manual/Connecting_hardware/Z_probe_testing#calibrate-the-z-probe-trigger-height

Ian

[Snippy]

@droftarts
Warning: the height map has a substantial Z offset. Suggest use Z-probe to establish Z=0 datum, then re-probe the mesh.
378 points probed, min error -1.674, max error 0.051, mean -1.157, deviation 0.336
Height map saved to file 0:/sys/heightmap.csv

RepRapFirmware height map file v2 generated at 2025-02-22 20:45, min error -1.674, max error 0.051, mean -1.157, deviation 0.336
axis0,axis1,min0,max0,min1,max1,radius,spacing0,spacing1,num0,num1
X,Y,0.00,400.00,0.00,400.00,-1.00,20.00,20.00,21,21
0, 0, 0, -0.605, -0.800, -0.884, -1.019, -1.089, -1.116, -1.179, -1.183, -1.143, -1.120, -1.058, -0.961, -0.838, -0.719, -0.471, -0.333, -0.113, 0.051
0, 0, 0, -0.675, -0.775, -0.954, -1.056, -1.180, -1.183, -1.220, -1.180, -1.185, -1.170, -1.103, -1.048, -0.930, -0.776, -0.600, -0.391, -0.270, -0.060
0, 0, 0, -0.748, -0.904, -1.031, -1.089, -1.210, -1.211, -1.238, -1.233, -1.254, -1.203, -1.158, -1.091, -0.970, -0.830, -0.620, -0.461, -0.331, -0.129
0, 0, 0, -0.828, -0.978, -1.079, -1.143, -1.230, -1.265, -1.275, -1.261, -1.285, -1.261, -1.185, -1.111, -0.988, -0.903, -0.738, -0.518, -0.384, -0.235
0, 0, 0, -0.900, -1.009, -1.120, -1.199, -1.276, -1.316, -1.351, -1.334, -1.295, -1.266, -1.224, -1.124, -1.035, -0.971, -0.818, -0.628, -0.464, -0.349
0, 0, 0, -0.990, -1.073, -1.190, -1.268, -1.328, -1.373, -1.375, -1.401, -1.382, -1.338, -1.280, -1.254, -1.145, -1.046, -0.945, -0.783, -0.598, -0.480
0, 0, 0, -0.989, -1.136, -1.244, -1.271, -1.396, -1.386, -1.431, -1.460, -1.424, -1.394, -1.348, -1.275, -1.200, -1.129, -1.021, -0.856, -0.704, -0.516
0, 0, 0, -1.059, -1.146, -1.230, -1.348, -1.399, -1.401, -1.458, -1.435, -1.471, -1.429, -1.400, -1.360, -1.253, -1.128, -1.063, -0.945, -0.784, -0.619
0, 0, 0, -1.106, -1.209, -1.278, -1.355, -1.419, -1.449, -1.485, -1.490, -1.471, -1.474, -1.399, -1.348, -1.263, -1.191, -1.078, -0.971, -0.815, -0.666
0, 0, 0, -1.110, -1.191, -1.298, -1.339, -1.408, -1.441, -1.489, -1.513, -1.501, -1.479, -1.464, -1.390, -1.305, -1.215, -1.149, -0.993, -0.919, -0.704
0, 0, 0, -1.096, -1.189, -1.280, -1.344, -1.451, -1.469, -1.513, -1.519, -1.531, -1.508, -1.497, -1.408, -1.291, -1.253, -1.141, -1.015, -0.884, -0.719
0, 0, 0, -1.074, -1.191, -1.294, -1.368, -1.438, -1.463, -1.441, -1.519, -1.550, -1.549, -1.479, -1.426, -1.341, -1.250, -1.174, -1.054, -0.930, -0.760
0, 0, 0, -1.073, -1.165, -1.308, -1.382, -1.439, -1.421, -1.505, -1.546, -1.551, -1.556, -1.499, -1.438, -1.350, -1.258, -1.104, -0.994, -0.853, -0.789
0, 0, 0, -1.015, -1.134, -1.243, -1.356, -1.461, -1.454, -1.519, -1.570, -1.531, -1.509, -1.460, -1.398, -1.344, -1.268, -1.106, -0.966, -0.840, -0.730
0, 0, 0, -0.978, -1.141, -1.239, -1.335, -1.398, -1.504, -1.528, -1.513, -1.558, -1.529, -1.485, -1.440, -1.274, -1.264, -1.111, -0.974, -0.870, -0.684
0, 0, 0, -0.963, -1.093, -1.264, -1.308, -1.446, -1.535, -1.539, -1.504, -1.551, -1.511, -1.485, -1.411, -1.270, -1.238, -1.115, -1.011, -0.853, -0.670
0, 0, 0, -0.903, -1.123, -1.273, -1.364, -1.435, -1.510, -1.540, -1.638, -1.565, -1.523, -1.438, -1.393, -1.313, -1.148, -1.059, -0.859, -0.734, -0.438
0, 0, 0, -0.886, -1.054, -1.238, -1.360, -1.470, -1.483, -1.593, -1.606, -1.634, -1.499, -1.463, -1.420, -1.233, -1.136, -1.018, -0.889, -0.655, -0.490
0, 0, 0, -0.893, -1.041, -1.201, -1.326, -1.456, -1.538, -1.558, -1.581, -1.623, -1.458, -1.550, -1.406, -1.240, -1.071, -0.921, -0.755, -0.531, -0.239
0, 0, 0, -0.803, -1.013, -1.186, -1.266, -1.478, -1.486, -1.531, -1.596, -1.548, -1.604, -1.414, -1.368, -1.214, -1.053, -0.858, -0.620, -0.405, -0.129
0, 0, 0, -0.789, -1.018, -1.173, -1.314, -1.465, -1.564, -1.658, -1.674, -1.616, -1.563, -1.483, -1.334, -1.213, -0.993, -0.819, -0.514, -0.275, -0.075

Got this far again, No matter where i try to establish the Z=0 datum allways the same error.
What i can tell from this height map that it is the most accurate so far.
Still the height map does ''jack shit'' when it comes to printing, nozzle wont go Z- It can only go Z+.
Why???

[fcwilt]

@Snippy

G1 Z-1.97 F50 ; Nozzle Z0 Y200 X160
G92 Z0
G1 Z5
G30 S-1

Why are you doing the G92 Z0 - that is quite likely going to mess things up entirely.

Before you can use mesh compensation you first have to insure your Z probe is correct configured so that setting the Z**=0 Datum**, using G30, gives the correct result.

After doing a G30 (usually at the center of the bed) you can then, using the DWC, "nudge" the bed toward the nozzle of the hotend. When the bed just touches the top of the nozzle the DWC should report the Z position as 0 (zero).

If it does not you need to adjust the Z trigger height of your Z probe configuration until you do get Z=0 when the bed just touches the nozzle.

It will like take several attempts to find the exact value you need for your Z probe.

Once the Z probe is working then and only then can you create an accurate height map. You must always use G30 to set the Z=0 Datum BEFORE using G29 to create the height map or when loading the height map.

Frederick

[Snippy]

@fcwilt
https://docs.duet3d.com/en/User_manual/Connecting_hardware/Z_probe_testing#calibrate-the-z-probe-trigger-height
This is why

[Snippy]

My problem is that after get a height map from G29 the map does nothing to compensate when printing, Z does not moove in -Z only in Z+.

[fcwilt]

@Snippy said in Z wont go to the corect dept when printing.:

@fcwilt
https://docs.duet3d.com/en/User_manual/Connecting_hardware/Z_probe_testing#calibrate-the-z-probe-trigger-height
This is why

OK - so the bed was just touching the nozzle at that point when you set Z=0?

Frederick

[fcwilt]

@Snippy said in Z wont go to the corect dept when printing.:

My problem is that after get a height map from G29 the map does nothing to compensate when printing, Z does not moove in -Z only in Z+.

Well how it should move would depend on the height map values and the height map value nearest to where the Z=0 Datum was set.

If the Z=0 Datum happened to be set equal to the lowest point of the mesh then movement would only be in Z+, as all of the other points, being higher, would need to be lowered.

Frederick

[Snippy]

@fcwilt Z datum was set to the highest part, So in order to print Z should go in the -
,

[Snippy]

@fcwilt
Yes

[sebkritikel]

@Snippy Can you post your config.g file? Specifically looking for your M208 line based on the following quote:

@Snippy said in Z wont go to the corect dept when printing.:

My problem is that after get a height map from G29 the map does nothing to compensate when printing, Z does not moove in -Z only in Z+.

Edit: Your bed does not look healthy lol.

[fcwilt]

@Snippy said in Z wont go to the corect dept when printing.:

Z datum was set to the highest part, So in order to print Z should go in the -

I assume you have verified that the Z axis moves in the correct direction when controlled from the DWC?

Frederick

P.S. Just out of curiosity what is the bed made from? It seems to have quite a bit of curve.

Here is the height map from one of my better printers. I had the bed created by a local machinist and it is very flat. Even came with a certificate.