Help Please - First Layer

Hi, I have had the lulzbot mini for a little over a week now and I am experiencing something unusual. As a clueless beginner, I have researched a ton but can’t find anything useful. My prints were coming out perfect for a while but recently started having a weird problem in spots of the first layer. I’ve changed nothing in my process of printing, up until I tried fixing this. Even with different bed temps, extruder temps, z offsets, using painters tape with and without heat, and sanding the bed with 1500 grit, I have had no luck trying to fix this problem with the first layer. The filament seems to either come out clear or not at all, but is then covered perfectly by the second layer. I do not think it affect my prints, but still, it would be nice to have something perform the way it is supposed to.

Thanks for any help you can provide. And by the way, I have no idea why the picture is upside down.


what is your first layer hight setting?
Can you check with a caliper if the first layer is printed according to setting?

All the Best

those clear spots are underextrusion. A regular pattern of underextrusion like that usually indicates that the nozzle is getting too close to the bed at that point. This can be due to a hump in the PEI, a lump in the bearing rods at that point (X or Y) or sometimes gummed up bearings that cause a nozle skip effect, though the latter isn’t likely due to the regularity of the pattern. It could also be on the extruder side, check the small gear setscrew and bearings, and also clean out the hobbed bolt.

If it is the nozzle getting too close, the usual fix is to increase the starting layer height (which should be around 0.40mm +/- 0.05mm for a 0.50mm nozzle and PEI).

Thank you for your help, but please remember that I am very new and very inexperienced. I am using Lulzbot’s Cura app, and if you could walk me through settings or things that need to be adjusted, that would be great.

Looks like the bed levelling was not completed properly. Watch the bed levelling like a hawk and if the bed gets pressed down more than a fraction then the nozzle is not clean and the level will be set wrong. It is possible to drive the nozzle into the PEI layer if levelling goes badly wrong, if this happens turn the printer off immediately and start again.