Z calibration
Hello,
Last night I did my first calibrations of the first layer.
I lowered Z to -550, but apparently I need to lower it further.
Question: Is there a safety feature that prevents the nozzle from hitting the plate when lowering?
No, you are calibrating the safety level.
If you are using the built-in first layer calibration routine then at the end of the calibration you are aiming to print a single layer postage stamp sized *sheet*. It should be possible to peel it off in one and fold it without the threads seperating. If it breaks into lines it is too high, not squished enough. If it is a single sheet but with wavy lines or drag marks on it you are too low.
If in doubt feel free to post a picture of the result of the calibration run *on the print sheet*.
Cheerio,
RE: Z calibration
You can speed it up by using something like my calibration strip https://www.prusaprinters.org/prints/105404 to test a range of values in one run.
Formerly known on this forum as @fuchsr -- until all hell broke loose with the forum software...