Find Yourself a 3D Printer - 3D Printing: Build your Own 3D Printer and Print your own 3D Objects - page 33

Figure 2.6 Note the finer resolution of the layers.
More and more 3D printers are coming that use the 1.75mm filament and the
0.4mm (or even smaller) diameter nozzle, and the benefits are definitely worth-
while: faster feed rate (the filament can be fed into the extruder and then into the
hot end at a faster speed), more detailed designs can be printed, and the motor has
to apply less power (torque) to feed the filament into the hot end. Still, the 3mm
filament shouldn't be discounted. A lot of prototypers and hobbyists like a larger
nozzle because it puts down more plastic in a single pass, and it takes less time
to print large objects (fewer layers). Keep all this in mind as you do your shop-
ping, but remember that filament in either diameter is just about the same price.
Buy a 3D printer based on what your printing needs are. If you're designing small
trinkets that might be used to create molds for jewelry, you'll probably appreci-
ate a smaller diameter nozzle and the detail it can provide. But if you're printing
out large gears for testing in your handmade robots, for example, a larger diameter
nozzle will get you those gears faster.