Nozzle is too close to the Bed when printing

Hello all,

Another issue here. I send out a G29 command which is bed leveling.

Then, I move the head to a neutral position.

Afterwards, I send out a G1 Z0 F1200 command to bring the bed super close to the nozzle. It is suppose to be about 0.5 to 1.0 mm away from the nozzle. But this time, it is 0.3 mm which isn't a big deal but where the nozzle was, it was effectively sitting on the bed!

So what parameters can I change in the configuration.h file to adjust the height of the bed at Z0 after the bed has been leveled? Or would it better to calibrate the height of the nozzle and leave the firmware as is?

You can tune the settings in the firmware, but you can also do it live through a USB connection with Host software like Pronterface. This way you don't have to flash the firmware every time and it works just as well.

The command to edit offsets is: M851

So when you type in M851 the machine returns the current offsets. If you want to set ONLY the Z-offset, you can send M851 Z[offset]

So if the probe triggers 1.1mm above the bed you set M851 Z-1.1

Always test this before starting a print, you don't want the nozzle digging into the bed surface. It's still a 'dumb' machine.

See this page for all info about the M851 command in Marlin: [marlinfw.org]

After setting the correct offset save it with M500 and load the config with M501 before you turn the machine off.

After making these changes you can go to your firmware and set this value so you don't overwrite it when you upload new firmware after changes:
Around line 964
#define NOZZLE_TO_PROBE_OFFSET { -40, 0, -0.55 }
These are my values, being X, Y and Z. So you want the -0.55 to match your personal offset.

Edited 1 time(s). Last edit at 08/18/2020 05:02PM by Ohmarinus.

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