I installed a BLTouch on my printer (Wanhao Duplicator i3) with Marlin 2.0.5.3 and enabled AUTO_BED_LEVELING_BILINEAR
.
However, the results are disastrous when I print. The first few layers do not adhere to the build plate at all. It is much worse with the probe than when I was leveling by hand.
In my Marlin configuration, I left the probe's Z offset from the nozzle at 0. Then I went through the Z offset calibration process to set Z=0 to barely touching the build plate. Then I ran the bed leveling process.
How can I diagnose what's going wrong?
When I run G30 X100 Y100
to probe the center of the bed, I get a measurement of Z=1.18. I'm assuming that represents the true Z offset between the probe and the nozzle tip?
Here's another thing I tried. I probed with G30 X100 Y100
which output a measurement like this:
Recv: Bed X: 100.00 Y: 100.00 Z: 0.06
I tweaked the Z offset with M851 Z...
repeatedly until a probe yielded Z: 0.00
(the offset was -1.07). Then I ran G29
to run bed leveling, which gave me this grid:
Bilinear Leveling Grid:
0 1 2 3 4 5 6 7 8
0 -0.403 -0.313 -0.258 -0.210 -0.178 -0.138 -0.128 -0.085 -0.058
1 -0.285 -0.223 -0.178 -0.145 -0.103 -0.060 -0.050 -0.023 -0.045
2 -0.178 -0.128 -0.080 -0.083 -0.078 -0.053 -0.045 -0.048 -0.038
3 -0.103 -0.058 -0.028 -0.030 -0.018 -0.015 -0.018 -0.000 -0.030
4 -0.020 +0.015 +0.015 +0.002 -0.000 -0.013 -0.035 -0.060 -0.088
5 +0.030 +0.055 +0.037 +0.020 +0.035 -0.015 -0.023 -0.073 -0.140
6 +0.060 +0.082 +0.087 +0.020 -0.000 -0.055 -0.103 -0.160 -0.210
7 +0.097 +0.102 +0.082 +0.055 +0.002 -0.035 -0.105 -0.138 -0.265
8 +0.145 +0.130 +0.102 +0.077 -0.045 -0.108 -0.183 -0.193 -0.263
You can see at (4,4), the center of the bed is 0.0.
Then I saved the mesh and Z-offset with M500
. I confirmed repeatedly that G28
puts the nozzle just touching the build plate and not pushing on it.
This strategy seems to be work alright. I'm not sure if it's the correct way to do it. I'd welcome any feedback. If anything, I think I should probably raise the nozzle a fraction of a millimeter higher off the bed.
M851 Zxxx
(where xxx denotes the offset)? $\endgroup$I tweaked the Z offset with M851 Z... repeatedly...
", you only need to do that once. $\endgroup$