Bauke/trebium,
The photo you posted shows symptoms that could be related to several settings. I haven't used cura much, so far, so I can't help there. But I can tell you some of my theories. (Remember, they're only theories).
- The perimeters and the first layer (i.e. the brim) look better than the infill. The first layer and perimeters are generally done slower than the infill, so either the speed is a little too high, or the temperature is a little low. The speed I curently run at, with PLA, is between 50 and 60 mm per second. If your speeds are close to that, they are probably OK. But for a quick test, while printing, just use the printer display and slow down the print ("Quick Settings", "Speed Mul." - try dropping that 20% or more for a while and watch the results). You can also increase the temperature in 5° steps while printing. But wait for one or two complete layers before increasing again, all the while observing the results. I would only change either speed or temperature per test. Messing around with two variables at the same time can really get you messed up.[b]
- I think you could be close with regards to the flow rate, but you need to get the temperature (and maybe speed) right before you start changing the flow rate. Deviating from the optimum flow rate will only cause problems with bridges (if the flow rate is too high), or cause the extruded bead to cut corners, making them rounded (if flow rate is too low), as well as reducing the overall strength of the item.
I suggest you print the exact same thing again, even using the same gcode file, but just raising the temperature
[b]OR slowing the speed. Let me (us) know if there was any improvement.
Also, it would be helpful if you post some of the general settings: nozzle size, layer height, temperature (first layer as well as rest), bed teperature (I think this isn't important in your case, but you never know), one or two significant speed settings (i.e. perimeter speed, infill).
I know that Slic3r includes this data at the very end of the gcode file, so there it would be a simple matter of cut & paste.
mjh11