"Odd" sized nozzles, how to use them?  

A few guidelines for differing nozzle sizes

Posted by: @tg-2

My first time here. I recently bought a set of V6 compatible nozzles from Amazon that were dirt cheap but had good ratings.

Those cheap nozzles may be OK for basic testing, but they often cause problems. Once you've identified the sizes you want to work with, investing a few bucks in quality nozzles is worthwhile.

I have had a good print so far with 0.6mm size but want to try the 0.2mm size. The only problem is that there is no profile for 0.2mm in Prusa Slicer. When the GCode is run on the printer with the size manually adjusted in Prusa Slicer, it warns before the print.

This is caused by a setting on your printer. It will issue a warning if the nozzle size set on the printer menu and the size your gcode was sliced with don't match. (I personally turn these warnings off since I frequently use "non-standard" nozzle sizes.)

Is this a case of "it's close enough to 0.25mm so use that"? I also have a 0.3mm nozzle and am not sure how to use that one. The 0.4mm preset is closer in size but I wonder if I ignore the printer warning whether it should just work.

There are some general guidelines:

• Keep layer heights below 80% of your nozzle size (extrusion width). Any higher and you get rounded extrusions which can have poor inter-layer adhesion.
• Keep extrusion widths below 120% of your nozzle size. With quality nozzles, you can usually push this to roughly 200%. Beyond that and the filament will squish out at the sides and yield rough prints.
• Be aware of the maximum volumetric speed (MVS), the rate that your hotend can handle. With larger nozzles, MVS can usually go higher. With smaller nozzles, it is reduced. 

I've got a bunch more notes here that might be of interest. 

Re: A few guidelines for differing nozzle sizes

Thanks for your tips @bobstro. I just printed a piece I needed precise dimensions for (a socket for fiber patch cable) and it printed very well. So looks like my fears were misplaced. I'm printing a second test piece with the 0.2mm nozzle (diameter verified under a microscope using the 0.8mm nozzle as reference), but this time with the 0.25mm profile. I'll report back how it goes. If this works well, I'll try out the 0.3mm nozzle with the same profile as it's again 0.05mm off. The 0.4mm would be 0.1mm off.

TG

"Odd" sized nozzles

I am using a 0.2mm hardened steel nozzle for my modelling prints. It is possible to redefine the nozzle size 'on-the-fly' in the Prusa Slicer and that might be sufficient. In my case though, much trial and many errors have been needed to get a satisfactory print. I only use PLA at the mo. Things like getting a good Z first level calibration (lower and fatter than the displayed pictures), changing nozzle size of course, retraction needs careful adjustment, travel speed needs to be slower than standard, temperature adjusted to suit the paticular PLA I am using.

I attach a gcode object which might help. (This is very thin model train axleboxes and support rods.) I have just exported my configuration and attach it too.

Tony