Prints are warping

[TRATOON]

I keep setting G92 Z0, but whenever the printer finishes probing or I restart the printer, it goes back to old height

[TRATOON]

@Günter-Jibben @infiniteloop Actual Z0 for me is -1.35 from where it is now. I set it as Z=0 using G92 Z0, but it keeps going back to the original position, after probing and after restarting the printer.

[engikeneer]

@tratoon if you are using a probe, you shouldn't be using G92.

Set the z offset of your probe correctly in G31 in config.g. your z axis will be set to this value when the probe triggers

[TRATOON]

@engikeneer But to get a Z offset, don't I need to tell the printer where Z0 is and isn't G92 telling the printer where Z0 is?

[TRATOON]

@engikeneer So will my printer always set Z0 to where the probe is triggered, and I have to ell it (using the Z offset) where to put the nozzle in relation to the Z0, set by the probe?

[TRATOON]

@engikeneer And how do I stop a " the height map has a substantial Z offset. Suggest use Z-probe to establish Z=0 datum, then re-probe the mesh.
30 points probed, min error -1.656, max error -1.329, mean -1.461, deviation 0.088
Height map saved to file 0:/sys/heightmap.csv" warning?

[engikeneer]

@tratoon you can use G92 once when determining the z offset, but not after.

My preferred approach is to set G31 Z0 (I.e. zero offset). Then probe the centre of the bed with a single G30. Then move z down until the nozzle just touches your bed. For a BLTouch, should be 1-2mm ish. Whatever that value is goes in G31 Z

You can then tweak it a little bit if you find your first layer is too squished, or not squished enough

[TRATOON]

@engikeneer Thank you very much, that solved my problem

[engikeneer]

@tratoon re the warning message on the heightmap, you need to home z using your probe before creating your heightmap and before you load it. If you don't, it doesn't know where z=0 is (or thinks it's in the wrong place) so the heightmap ends up offset

[TRATOON]

@engikeneer I just needed to set the Z Offset, what you are saying doesn't make sense, as the printer won't probe unless all axis are homed.

[engikeneer]

@tratoon yes thats right.

However if you use a G92 Z0, or home Z with an endstop instead of the probe, it will allow you to run mesh, but you may get the error

Also, now you have created a mesh, you don't have to reprobe the whole bed every print, you can just load the existing heightmap that is now saved to the SD card with G29 S1. I have a 400 point mesh for my printer that takes over an hour to run, but is stable enough that I only have to redo it if I take the printer to pieces. I just have to make sure I home z with the BLTouch before I load the heightmap for each printer.

[TRATOON]

@engikeneer , @infiniteloop, @Günter-Jibben I just started a print, and I used baby stepping to lower the nozzle during the first layer. However, when the second layer started printing, the nozzle was too low and was scraping the part, and that caused my filament sensor to pause the print as it was at 2% extrusion. Why is it that the nozzle had to be lower for the first layer but higher for all the layers after that. For the first layer, the babystep offset was -0.20, and for the layers after that, it had to be 0.04 is this normal, because I don't have this issue on my other 3D printers.

[infiniteloop]

@tratoon said in Prints are warping:

For the first layer, the babystep offset was -0.20, and for the layers after that, it had to be 0.04 is this normal?

Definitely not. Either the steps/mm for Z are wrong, or the nozzle pushed the bed down on the first layer. A third reason I can imagine are wrong settings in the slicer (1st layer height?).

[TRATOON]

@infiniteloop first layer height is 0.3 rest are .25

[TRATOON]

Nozzle didn't push bed down as the nozzle was 2mm higher than the bed

[TRATOON]

And on the fifth layer or so, it completely stopped extruding. And I had to push filament into the extruder and then it would extrude. What is going on?

[alankilian]

@tratoon Is it possible you have the wrong filament diameter set in your slicer?

Or you have extrusion set to some amount other than 1.0?

Can you post the STL and GCODE for your 20mm block again and I'll compare to my settings.

[TRATOON]

@alankilian Which 20mm block?

[TRATOON]

@alankilian Here is a XYZ calibration cubeCube.gcode

20220711_XYZ_Calibration_Cube.stl

[TRATOON]

@alankilian My filament diameter is correct. I looked up "extrusion" in Cura no relevant setting, so by that, I think you mean flow, which is set to 100%