Adjust the Z while printimg the first layer

The Z of my prusa printer is changing a lot with different bed temperatures. It would be great to mannualy adjust the Z (with the lcd knob) while printing the first layer. Is this possible?

(prusa i3 running marlin)

I know this problem, too. But my solution is to simply finetune the Z-level of my i3s manually by turning the Z-couplings slightly while the skirt of the first layer is printing. For this, you must make sure that the Z-motors are disabled when not moving (#define DISABLE_Z true) so that the Z-motors rotate easily when not moving between layers. It takes a little practice to rotate both couplings in the right direction until the extrusion width is what you want it to be. But once you get the hang of it, it's really easy and the result is as good as using ABL - IMHO even better, because I can adjust the first layer height for each print individually (some objects need more, some less "pushing").

You can enable babystepping. Marlin has this feature. With that you can easy adjust Z while printing the first layer.

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Triffid Hunter's Calibration Guide

--> X <-- Drill for new Monitor

Most important Gcode.

Was going to mention baby stepping also.

I did not know you could disable the Z steppers between Z moves. I guess that does make it easy to hand-turn the couplings.

That's it! Babystepping is enabled and working very well.

Thanks.

I have to look into this because I have nothing but issues with my Z height.
The bed has been leveled with a dial indicator to about .001" all around. My problem is that I can set the Z height before a print perfect but once the print is started and re homes the Z can be off by quite a bit. Im not sure whats up but its REAL annoying that I can print perfect 50% of the time and the other I have to reset the Z height before I print.

Sounds like a heat-warp issue, or a loose frame.

Simple solution: don't re-home the Z axis at the start of a print. Remove the G28 command from your slicer start gcode, or change it to G28 X0 Y0.. Either set the Z=0 height manually before starting a print, or use a Z probe and a G30 command in your start gcode to find where Z=0 is.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].