Print fails at perpendicular boundaries I recently changed the printhead on my DeltaMaker from stock to an E3D Lite6, and am struggling to get back to my original quality, reliability, and repeatability.  I thought I had gotten the recipe pretty close to dialed in and tried a bigger print last night.  It turned out pretty good in most respects except for where vertical structures rise up from the horizontal surface (and a retraction/stringing issue that I didn't think was but perhaps could be related).  

The screw hole mounts seem well-designed to me:



No 90 degree transitions - I would think this would be the least of my problems.  But last night they had serious problems:





I haven't seen a problem like that before.  Extrusion rate seems basically perfect - why does it look like it just stopped extruding around the perimeters?

I'm using PLA filament and Simplify3D 3.1.0 slicing.  Settings:


0.35 mm nozzle, 0.40 mm extrusion width, 1.05 extrusion multiplier
0.15 mm layer height, 3 top, 3 bottom layers, 2 perimeter shells (maybe should try 3?)
30% infill, 60% outline overlap, 110% infill extrusion width 
Temp is 220°C (thermocouple wedged between nozzle and heater block reports about 206°C when thermistor says 220°C) 
Print speed is 2700 mm/min (45 mm/s)


Has anyone seen this issue before?

UPDATE:
Increasing outline overlap from 60% to 90% almost fixes the problem (at least visually if not structurally) - there's just one small hole at the base of each structure.  (I stopped the print a few layers after the problem layers do ignore the tops.)



Going to 99% (Simplify3D's max) would probably get rid of those last holes but I have to think that maxing out S3D's outline overlap setting to just barely make the print work means I haven't found or addressed the true root cause...
Since you said you don't have a cooling fan, try lowering the temperature on your print head to something like 205. The strings in the first and second picture also occur more often when the print temperature is too high as well. 

The layer time gets really small at that transition, so make sure the print speed is slowing down while printing that part of the object and pausing in between those layers to allow for cooling.

It looks like the plastic is still molten and is being dragged around too me.