Active Leveling... not level?

[bjennings 0]

I'm having an issue where the print bed is seemingly not level. I can't print anything toward the back of the build plate because the extruder touches the glass and no material gets extruded. Then once the extruder comes farther forward, it makes up for lost time and extrudes enough material to make the nearby landfill salivate. You can see in the picture how the brim is translucent near the back of the print but nice and dark near the front.

I've done manual leveling several times, meticulously following the directions trying to fix it. The machine then active-levels and starts printing. Same problem every time.

I've been able to minimize the problem by only printing toward the front of the build plate and gotten some successful prints that way, but I can't figure out what's wrong and this severely limits what I'm able to do with a brand new UM3e. Am I doing something wrong?

[tomnagel 85]

Please check if your glass plate is flat, e.g. with a ruler. There have been reports of unflat glass, and your reseller will help you if yours is unflat.

(0.2 - 0.3 mm flatness over the whole plate is good enough, most will be compensated by active leveling, and the remaining tolerances are absorbed by the first layer).

Are you using the default 0.27mm first layer thickness?

Since the active leveling uses 3 measurement points, the shape of the glass does matter. Rotating the plate 180 degrees (keep same side up!) could help as well.

[bjennings 0]

Sorry for the delay. I got my build plate onto a machinist inspection table and it looks like the flatness is within 0.18mm. I marked my plate's edge in one corner and I'm going to start experimenting with orientations. I'll let you know what I can find.