Lines, marks, and bumps with ABS

[j3d 0]

Any idea what causes these blemishes? The lines are openings in the side of the print. 260 deg C material, 90 deg C build plate, 49% fan after first few layers. The bumps seem to be on the top layers, but doesn't seem like pillowing as shown in the guide. Could the marks be burnt material?

Link:

[pm_dude 27]

You do seem to have burned materials. I get these with XT sometimes. Make sure your nozzle is as clean as possible and no burned material is stuck on it otherwise it can stick to the extruded material and attach to your print.

Aside from that you also have under extrusion. What speed are you printing?

 

[j3d 0]

I'm printing at 50mm/s.

Would humidity be a factor? It started raining part way through, and while the UM2 is in a climate controlled room, the window right behind it was open, for ventilation.