Prusa MK3S 0.8 mm nozzle layers separating I am currently printing a simple cup out of PLA (I will later anneal it). My nozzle is 0.8&nbsp;mm and I'm using a 0.4&nbsp;mm layer height. Unfortunately, the layers keep separating. They don't detach completely, but there are 1 layer-tall, 3-7&nbsp;mm wide gaps. I increased the temperature, since my speed is 100&nbsp;mm/s. I also tried decreasing cooling and increasing the flow. This only helped a little bit. 

Moreover, small increases in the temperature like 230/240&nbsp;&deg;C didn't work and now I have to use 270 and even 280&nbsp;&deg;C, which is crazy, considering my layer height is 0.4&nbsp;mm. Is there any easy solution that will increase the quality?

Settings:


Material: PLA
Layer height: 0.4&nbsp;mm
Nozzle: 235&nbsp;&deg;C first layer, 270&nbsp;&deg;C for the rest.
Bed: 60&nbsp;&deg;C
Cooling: 62&nbsp;%
Speed: 100&nbsp;mm/s


I have noticed that 280&nbsp;&deg;C is better for large prints (large area, not height) and small prints look better when I change the temperature to 240/250&nbsp;&deg;C.
This is how my prints look by now. The extrusion is very inconsistent, with overextrusion in the middle of the layers and gaps in the corners:





I suspect that the layer lines are not parallel to the heatbed and are over extruded, because of the high temp. I lowered it to 230&nbsp;&deg;C and there was no drooping/over extrusion, but there were more 'holes'.
After printing ~30 calibration test cubes I finally figured out the perfect settings. 

Apparently, the extrusion width in my slicer was set to a certain number, instead of 
percentage. I was printing at 0.45&nbsp;mm extrusion width, which was ~105&nbsp;% of the 0.4&nbsp;mm nozzle diameter, but less than 50&nbsp;% of the 0.8&nbsp;mm one. Changing the value to 130-140&nbsp;% 
solved the majority of my printing problems.

As I predicted, the 230-280&nbsp;℃ nozzle temp. was ridiculously high, even with the 
0.8&nbsp;mm nozzle.  I gradually lowered it to 210&nbsp;℃ (ironically, the value I chose at the very beginning). 
 There was some warping, so I cleaned the heatbed from the glue, put the glue again and decreased bed temp. to 50&nbsp;℃
 Finally, I decreased the flow from 1.3 to 1.05 and everything seems perfect now.