First Layer blobing/smearing issue

Mini v1
Windows
Cura 3.2-3.6

Anyone seen this before? I’ve had this issue for a good 6 months on and off. I cannot seem to find much of anything online about it. At first I thought it was a maybe a Z-height issue. Which bringing up the Z-height did solve it, but then it went back to doing this off and on again. I’ve used 3 different beds throughout this, too (standard v1 bed, modular, then new modular glass, and even new 3rd party PEI sheet).

Initially, the printer never did this regardless of Z-height. I could smash it into the plate or float it higher, it was always a line. never blobs. Now I am walking a very fine line between not sticking and the blob result above. And even if I find that fine line, it’s a 50/50 chance on blobs still.

(the rest of the print once it gets above layer 2 or so is perfect, still)

It will do this and not do this with no setting changes as well. So also has me wondering if the auto calibrate is not working well. Any way to shut that off either?

Your initial nozzle height is too close to the bed. The “smears” happen when the pressure builds up enough to push the bed down, releasing the filament.

Most likely the autolevel on your Mini is not functioning properly because of a thin layer of filament on the nozzle or discs from ooze or a dirty/worn cleaning pad. The thin layer of filament causes the the nozzle to depress the discs rather than just touching the disc for continuity.

To remedy, thoroughly clean the nozzle and disc surfaces. Then change (or flip) the cleaning pad. Watch the level process and make sure the bed is not being depressed at any point.

Hope that helps.

Great, thanks for the feedback. I was playing around in that direction with mixed results, I’ll give it more attention. I was sweeping the Z-height by as much as .2 (in .02-.05 steps).

I’ve been cleaning things quite well, but I will check that the bed is not being depressed, haven’t thought of that, great point.