White PLA prints frequently have rough sidewalls near top of the print This has happened a few times whenever I print with the white PLA (Hatchbox 1.75 mm). It seems that the print job produces smooth sidewalls for most of the part but at a certain point and above, the walls become rough as if the alignment is off or something. I've attached a picture to show the issue. Does anybody have any insight?



I'm using a Printrbot Simple Metal and some of the print settings are listed below:


Slicer: Slic3r
[First] Layer height: 0.2 mm
Perimeters: 2
Solid Layers [top/bottom]: 3
Infill: 25%
Fill pattern: Rectilinear
Top/Bottom Fill pattern: Concentric
Perimeter speed: 30 mm/s
Infill speed: 80 mm/s
Travel speed: 150 mm/s
Acceleration (perimeters): 1000 mm/s2
Acceleration (default): 3000mm/s2
Default extrusion width: Slic3r chosen
Print temperature: 220°C


I've noticed in the Slic3r rendering that the affected area seems to be the point where the infill switches from 25% to solid as seen in the included picture. If this is the problem, is there any way to enforce solid infill a few layers below this to eliminate the awkward transition, or specify a smaller extrusion width at this point?
If you want to change settings on some area of your part check out modifier meshes in Slic3r.

It looks like to0 much heat is delivered when solid infill starts and some melting occurs. See 3D Printing Problems #22: Extrusion Temperature Too High. 

You can try:


Lower extrusion temperature
Lower filament flow
Improve part cooling
Lower print speed