Auto bed leveling: systematic slope I have a heavily modified DiscoEasy 200 from Dagoma, see picture:



The heatbed is mounted on 4 springs, on top of the original plate. I made sure the X carriage was parallel to the table. I then tried to level the bed manually, with the 4 springs: I pushed the nozzle into each corner of the bed, and used the paper-gauge method to adjust the springs so that the bed would always be at the same distance of the nozzle. I then setup the Z-offset on the machine and tried to print a mainstream bed leveling test from thingiverse. I use a 4 points auto bed leveling.

And I have a systematic problem. Every time I try the bed leveling test, it seems the right side of the bed is lower than the left one. The front and rear right corners seem to be lower than on the left side. I tried to expand the springs of the front and rear right corners, but the auto bed leveling at the beginning of my prints re-introduces the problem.

The right side seems to be ~100 µm lower than what it should be. It's not a lot, but it's enough for prints to fail.

I can't figure out what the problem is. Do you have any idea? it's driving me crazy to not understand where the problem comes from.
Did you check if your bed is parallel to the gantry? 

It can happen that after leveling one side and moving  to the other the adjustment there puts the first side out of alignment - I level my bed by doing some couple turns