I have a bltouch clone which work fine on glass bed. After switching to textured PEI sheet, it’s variance trippled to 0.1mm, which make my bed mesh all wobbly.
I’m I suppose to remove the steel plate when making the bed mesh? Do you home Z with a probe with this setup?
The weirdest thing is, despite all this all my prints adhere completely fine. I guess PEI is just that good.
I use marlin UBL with a bl touch. On textured sheet. The first thing is to recognize it’s supposed to have that variance.
I found that increasing the first layer extrusion width (140%, normally I’m at 110% unless I need a strong and ugly part,) and juicing the extrusion multiplier slightly helped.
My calibration process for z offset was:
-turn off software endsroos. (M211 s0; use s1 to turn them back on. This allows you to go negative positions.)
Then I probe the mesh and save it to the board. (And recall it on the print start gcode and do a 3x3 probe to tilt the mesh into position.)
What I have found is that it slides a bit with the magnetic base- especially on heavy/fast prints invalidating the mesh.