I've just started getting this issue out of the blue. I've changed nothing else on my Prusa i3 printing ABS at 230C with a bed of 110C. The first layer is lumpy almost all the time now. The rest of the print is beautiful as I have my printer nicely calibrated. I've tried enclosing the printer to minimize drafts and that's not helping. I'm using AquaNet on the glass and that's always worked perfectly. I tried 110C for the bed and that didn't help.

I couldn't find any posts about this issue here. Has anyone seen this problem before?

Edited 1 time(s). Last edit at 02/04/2014 12:35PM by RobH2.

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Prusa i3 8" (Makerfarm) / Dual Hexagon 0.4 extruder

The plastic is not sticking to the bed. Most likely the glass wasn't squeaky clean before the AquaNet was applied.

Thanks Stephen. I think I'm doing a pretty good job with glass cleaning but will be more fastidious going forward.

I've been using KISSlicer and getting incredibly nice prints for about a month. I just started a test with Slic3r and it's not doing the lumpy problem so I think it might be KISSlicer that's malfunctioning somehow. I spent about 4 hours trying to get the problem solved before posting. I wish I had thought about changing slicers first. But, if the problem does come back I'll have to look at my cleaning protocol again. Thanks for the fast answer.

came here to report exactly the same problem. Using kisslicer as well, although I'm printing PLA. I found that reducing first layer flow to 70% greatly helps, but I'm using lcd controller to do it so it's fully manual process.

Image of what I'm getting: [www.dropbox.com]

Bed is clean, changing extrusion/bed temps doesn't help much. Don't remember having this problem with slic3r.