After few good prints with my new Ender 3, I noticed that prints with longer shell straight lines (> 5 cm) have extrusion problems in the middle of those lines.
I figured that this might be because the printing speed (70 mm/s) and filament temperature (210 °C for PLA). So I increased my filament temperature about 215 °C and lowered print speed to 60 mm/s. I am using Cura v3.5.1. For the next few smaller prints everything was perfect.
Now I am printing a bigger 128 mm X 48 mm rectangular shape. In the middle of the 128mm line of the outer shell, I have signs of under extrusion. Looks like dents.
I also notice that the head is really fast during this 128 mm travel. No way ~2 seconds would take 60 mm/s to travel 128 mm. It is more like 1 second or less.
Why would my head travel at such speeds?
I am attaching my speed settings.
I am attaching the image of the printed piece and the defect generated.