Nozzle hole size is one factor that determines possible extruded line width, height and extrusion amount. Those are variables that are altered depending on size and strength of the item to be printed.
Bigger hole size is of course more plastic flow and smaller is less. But there are other adjustable variables that affect the actual flow amount. It’s all a game of balance and tuning to get the exact extrusion flow desired or required for a good print.
The smaller the hole size the more critical all the adjustable setting factors become and lowers the flow rate considerable amount. Also greatly increasing the print time.
Standard range for nozzle hole size is between 0.20mm up to 1.0mm on hobbyist machine with 0.20mm to 0.60mm (0.40mm standard) as the most common.
I have used the 0.20mm size nozzle on occasion. Used mostly for very small prints of very high detail. Also requires very long print times.
Today I have been using the 0.60mm nozzle on a small project. I see that I have been missing some of the benefits of using the wider nozzle. A wider extrusion is laid down so fill-in and wall pass counts can be reduced and extruding run at higher print speeds. Ninety plus percent of my prints really don’t require printing with a 0.40mm nozzle.
I now realize there is nothing sacred about the “standard” 0.40mm nozzle. It’s pretty much all purpose, but that doesn’t mean it’s the best choice for every print.
I think I will be using the 0.60 size nozzle much more often. Especially where I don’t need super-fine layers and fine details.
The photo is a small box printed with 0.30mm layer height and a 0.60mm nozzle using PETG. The results are great! Looks like an old pair of blue jeans. The filament is Overture brand called Stary Night (blue). I can see the stars!