Each of your prints built-up out of several layers which again consist perimeters (the Outlines of the Print) and infill. If you notice small gaps between the perimeters (Outline of the print) and the infill, then there are two topics which you may want to check.
Adjust the printspeed
If you are printing too fast, it can cause layer shifting or a poor print quality. With high printing speed, it could happen that your belts slips over the cogwheel/drive pulleys and your tool head/hotend will lose the right position.
You can adjust the printing speed like on the pictures below.
If you were printing at 3600 mm/min or 60 mm/s (the most common printing speed), try decreasing that value by 50% to 1800 mm/min or 30mm/s to see if the filament grinding goes away or print quality increases. If not, it´s very likely that the problem is a different one. If the it works out, try to increase the printing speed in small steps till you find the best balance of a good quality and printing speed.
To prevent your print of failed overhangs or to reduce support structure, it is also possible to reduce the layer height in your slicer software.