Ender 3 Pro: How to solve the issue with different Z-offsets?

Question

I have an Ender 3 Pro with BLTouch (original) and did at least a dozen of test prints to adjust everything (steps/mm, ...). I did everything at the target temp of PLA.

But I've still got the problem that if I print, my 1st (and possibly 2nd) layer print fine (i.e. good bed adhesion, first layer is almost perfect 0.2 mm high) with -2.575 mm Z-probe offset (M851 Z-2.575) and for consecutive layers I need to reduce it to -2.435 mm to not have the nozzle drag inside the print. So there is a "step" of 0.14 mm.

I previously used the paper method to adjust the bed height as usual and followed the instructions widely available. I'm using Marlin 1.1.9 firmware (custom compiled, latest version of 1x-branch).

Any ideas what causes this issue and how to get rid of it?

Answer 1

Try adjusting the height of your Z stop switch. If it's in weird spot to start,it can effect the stepper motor's ability to do the next couple of levels correctly. Took me hours and hours to figure that out to be the problem. Good luck.