This next one even had us stumped for a few days. In the picture below you can see how the top surfaces of the print are all fuzzy. Why is this print fuzzy at the top, but smooth on the other surfaces? It is all the same smooth texture in the model and Simplify preview.
Here is a closer look at one of the fuzzy sections:
Might be wrong but heres my guess:
Overhangs need support, even on the inside! Its easy to forget but this model was printed with to little infill, maybe to few top layers aswell, so the continues heat buildup on printing the perimiters builds up and the PLA(?) curls upwards during printing resulting in bad surface quality.
Higher infill, maybe more top layers, and you could mitigate this quite good i believe, and better cooling always helps with overhangs :)
Edit: More perimiters could also help :)
Outline direction was Inside-Out, very low or no infill and not enough outlines/perimeters.
@Sigbjørn Thorsen
Overhangs need support, but Gigabot can handle a 70 degree overhang. Assuming that the inside doesn't support the outside at all, there are sections that are fuzzy that are well within Gigabot's capabilities.
This part is printed in ABS with 5% infill and 3 perimeters.
Keep guessing!
Couple guesses for consideration:
I have had filament quality change mid-spool. Filament diameter, contamination, or dryness may have changed during the latter-part of the spool. Filament diameter change would result in over- or under- extrusion, and moisture or contaminates can result in uneven extrusion rates as the filament gets very hot just before exiting the nozzle. Did the filament quality change during the later part of the print?
Considering that this print was in ~October: I have had temperature swings in the printer's environment change print quality... especially overnight and especially when the building's thermostats are on timers and not maintaining a stable environment. This could be true with environmental humidity, too, although when I have dried ABS it seems to take at least 3 days before it needs to be dried again. Did a temperature/environment change occur during the course of this print?
This was printed inside a full enclosure, so if the office temperature did change, then this print should have been less affected by it. This was also not something we saw in any of our other prints around that time or since.
We have found ABS to not absorb much moisture, so we don't dry it. It should have been about the same humidity level for the entire print.
We did not inspect the diameter along the whole length of this spool before printing, but we print with material from this manufacturer every day and don't have that problem. I think the problem wasn't filament quality.
Keep guessing!