Nozzle Change 0.3mm Settings/Firmware?

I recently purchased a 0.3mm nozzle for use with 3mm filament to use on my TAZ5. I am using Cura for printing. I setup a second machine profile for this just to make switching easy but saw they don’t have a choice of 0.3mm nozzle. The only choices are 0.5 or 0.35. What do I need to change in order to use the 0.3mm nozzle besides the nozzle size setting. Is there a firmware change? Any other settings to change?

THe nozzle size setting is the main one. You may also want to adjust your layer height. A 0.35mm nozzle is going to lay down a bit more plastic than a 0.3mm one, so it will do a bit better with a bit thicker layer. You may want to lower your layer setting a bit, but still try to pick a layer height divisible by 5 (I think? Its been a while since I played with a 0.3mm nozzle, If you get it wrong, you may see excessive z wobble banding, if changing the number slightly makes it go away, you know you had the wrong one)

You will not need to make any firmware changes unless you are also changing the hobbed bolt out (i.e. putting a different print head on with a different e-steps calibration value)

Try the .35mm nozzle profile, and adjust the flow rate/multiplier. As piercet said, it may put out a little more filament than you want, adjust accordingly… dividing .30/.35 give is ~85%.

The attached STL, may help identify the correct multiplier setting for your setup (machine esteps, filament type). The two pieces should fit together. The pictures shows the .10mm tolerance of the peg to the hole.

Extruder Accuracy Test.v1.stl (52.5 KB)