This may be the single holy grail of pellet extrusion.
ugly prints are caused by 70% retraction, 10% pellet chemistry, 10% pellet geometry, 10% not extruder
retraction : see pressure and retraction, also affected by pellet chemistry
pellet chemistry : some formulation contain flow modifiers that keeps PLA from being too thin when hot. viscosity is important here. for example, PLA suddenly become water past 210c. PP dont change much even at 260c. ABS transitions smoothly inside its temp range. Try pelletizing a good filament and see how filament manufacturers have modified so much for printing, compare to pure counterparts. Sometime you print at exactly the right temp for the polymerr to oscillate between phases-> not good (see “temperature, flow, and extrusion width)
pellet geometry : the smaller the better, the more consistent the better. this affects how they stack together inside the screw channels. we want maximum occupancy.
not extruder : if your printer isnt set to print well with filament extruders (no input shaping, no LA/PA, incorrect slicing speed and settings) then pellet extruder will amplify 100x whatever’s lacking
Solution (1st degree- quick patch)
retraction : see tuning
pellet chemistry : print colder
pellet geometry : needs 2nd degree
not extruder : print everything at the same speed , much slower (see slicer settings)
Solution (2nd degree- actual fixes)
SOlution (3rd degree- restructure/compensate)