First layer oddity - partial failure
I have searched for answers to this issue in the past, but so far have come up empty-handed. For many of my prints with a large first layer surface area, part of the layer prints just fine, while other parts tear and pull and blob and do other weird things. This doesn't seem to happen when I print test such as the single layer calibration files, nor does it happen often on smaller prints. Can some please help me diagnose the issue that I am having? I have tried various combinations of nozzle temperatures, bed temperatures, speeds, etc.
Thanks so much
RE: First layer oddity - partial failure
I forgot to mention that this was PLA, 205 first layer, 70 bed temp.
RE: First layer oddity - partial failure
First - this is a common issue that folks on the learning curve hit. From the pictures, your first layer is too high. Calibration gets you 80% of the way there, but live Z adjustment gets you there - but it is not a magic one-time bullet. I often have to change live Z if I change filament brands, sometimes even filament color - for the same model.
The blobbing you are seeing is due to the hot head running into prior traces that have not adhered to the bed. They hit the hot head and start to build up as globs on the nozzle - these get so large that they later drip - creating the blobs on your print bed. Then those make things progressively worse because the heated nozzle runs into them, pick them up like a plow, and peel up more of the first layer.
Do bring your print head much closer to the bed with LIve Z.
Also, I like to recommend turning on the setting "7x7 mesh bed leveling" in the settings for the printer. It makes prints take longer to get off the ground (49 points are probed on the bed before starting the print) - but this makes any low-spot/high-spot issues on your print plate much less of an impact on the overall print.