It is often noted that 0.2 nozzle works better for fine detail than 0.4 ;
But is that really true ?
Using Bambu Studio and it’s presets for 0.2 and 0.4 , you can see what they recommend for layer widths, flow rates, etc.
So why not just use all of them in a 0.4 settings in the slicer ? Why bother with the 0.2 ?
as a parenthetic , are there start g-code considerations ? maximum flow and the like ?
The smaller you try and go on a large nozzle the harder it will be to achieve the details. The physical size of the nozzle has a limit to how fine the filament can be consistently. This is why you would want to switch to a 0.2, because the size is smaller it will allow for more consistent extrusion of smaller amounts. Feel free to give it a try, you will instantly notice the difference between printing a 0.1mm layer height on a 0.2 vs a 0.4mm nozzle.
As for gcode you shouldn’t need to change anything. As long as you change the nozzle size and the layer height in the slicer you should be good to go. Occasionally if I change to a 0.2mm nozzle I will have to do some adjustment to my z-offset, but not all the time.
What Matthew said is exactly right. The biggest reason not to go with a 0.2 nozzle is print time. One issue I have also had with 0.2 nozzles is clogging a lot more frequently than my 0.4s ever have.
Are the nozzle sizes (MK 10) close enough so that changes to the Z offset etc. are not required.
Depends on how precise your z-offset was originally set, the larger the layer height the less precise you have to be with your z-offset. Theoretically if it was perfectly set you won’t have to reset it. I will usually just double check the first couple prints that I do to make sure everything is hunky dory and make any adjustments needed.