• Ellis's Print Tuning Guide on First Layer "Squish"

(wip)

Generally speaking an otherwise uninfluenced extrusion from the nozzle will have a circular cross section. If an extruded line is placed next to another extruded line which each have a circular cross section they only tangentially connect. It will also only tangentially connect with the plate resulting in very poor adherence. A more rectangular cross section is desirable for maximal surface area connection. By adjusting the layer height very slightly we can control this shape and it will become more “stadium” shapped, flat on the top and bottom and rounded on the sides.

If we don't have good surface area connection in the extrusion lines the print will also be very weak and fall part on the layers.

• Material
• type
• brand
• color
• Build plates

• Examples (click to enlarge)
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The gcode z offset is set with the SET_GCODE_OFFSET klipper command and you should read its documentation, at https://www.klipper3d.org/G-Codes.html#set_gcode_offset All other methods of changing the value just equate to this command. You can set it to a absolute value like

SET_GCODE_OFFSET Z=0.075

or adjust it relative to its current value like

SET_GCODE_OFFSET Z_ADJUST=0.3

Fluidd provides easy to use controls and displays the current value, live.

Workflows using the Screen can be problematic as proper attention needs to be considered for how this value may be being changed by other controls. It is not displayed live and the value shown is often stale. This can result in issues when it send incremental value changes. The Screen does not send absolute adjustment values to Klipper, it send relative value changes. This means the Screen's understanding of the gcode z offset can differ from what it actually is, so if it still believes the offset is, say, 0.125, and it was really 0.200, when you adjust the offset on the screen by 0.100 that issues a SET_GCODE_OFFSET Z_ADJUST=0.100 command and the offset becomes 0.300mm and not 0.225mm. Saving it in the Screen's workflows can also trigger changes to other values unintentionally. It's better and easier to change the value in the console or in the Fluidd GUI.

The gcode z offset can be set by the slicer, yet this method is not recommended as the slicer then applies the offset value to all movement directives it produces in the gcode file.

You can set the gcode z offset as part of the printer configuration.

Follow the procedure described in How should I set the z offset.

No.

At best the paper method will asymptotically approach the thickness of the paper being used. Yet this is an arbitrary value nearly in the ball park of what a typical z offset might be. The z offset we're seeking is filament dependent and will vary by the filament being used. We're seeking a correct affect on the shape of the extrusion's cross section, a “smush”, and that can't be defined by some arbitrary height.

The same logic applies to using feeler gauges.

The Elegoo Centauri Carbon has sensors to “set the z offset”, yet it's setting the probe offset. Prints will often still require a gcode z offset adjustment.

See Probe Calibration

Diagram showing layer height composition.