First layer quality problem

[iras]

Hi,

I'm having a problem with getting a clean first layer on my Prusa i3 clone.

The first layer is not going doing cleanly". It has bumps and ripples. I printed one layer, stopped it, and took pictures of the top and bottom of the first layer (below). Otherwise, prints are good - if I let the prints complete, I get good adhesion (sometimes too good and hard to peel off).

I’m running PLA from various sources (Playphab, Hatchbox, etc.), 0.3mm nozzle. I've tried different bed temperatures between 45C and 60C with no difference. I'm running the printhead at 188C (which gives me great results otherwise as far as bridging, stringing, layer to layer adhesion, etc.). But I've also tried higher temps with no difference. This sample was printed on Buildtak, but I have the same issue on glass with elmer’s glue.

Any ideas what causes this and how to correct it?



Topside.jpg

Bottomside2.jpg