So yeah, spent the first week making large prints that look like dogshit quickly using the 0.6mm nozzle. Mainly because I borked my 0.4mm nozzle and had to order a new one, and I wanted to tune for that size first. Later on I will repeat the process for the other nozzle sizes I want to use. This is the tuning guide I have been following thus far:
https://ellis3dp.com/Print-Tuning-Guide ... uning.html
The first step that he mentions, tuning the extruder, is something I did when I first got the printer running, before I printed anything with it. Basically you tell the extruder to extrude 100mm of filament, measure how much it actually feeds, and then calculate a correction factor which will be included in the printer.cfg file the Klipper uses. Mine was pretty close to begin with, so the correction needed was really small. This is all done on the filament input side of the extruder; if you wanted it would be perfectly adequate to remove the hot end and just feed the filament though without melting it just to take the measurement.
Second, the Z-offset/first layer calibration. This is basically how close to the build plate the nozzle is set for the first layer, and determines how much the plastic is "squished" as the first layer goes down. The process is a little different on the Voron than my Prusas but your basically doing the same thing. The setting I had arrived at with the 0.6mm nozzle was somehow close enough (this is supposed to in theory be an advantage of the Revo, but I had expected to have to adjust it when switching sizes anyway) with the 0.4mm nozzle installed, so I proceeded to print a Voron calibration cube (one of the test prints included in the .stl package) just to have a baseline to see how the printer would do to start.
Next, I followed the guide for tuning Pressure Advance. This is a setting which will vary the amount of filament that is extruded as the print head changes directions (i.e. as it goes around corners). This should reduce bulging and artifacts adjacent to the corners of prints.
The calibration website contains a form into which you input some data for your printer, and it generates a g-code file that you print. The chevron features are printed at different increments of Pressure Advance, and you choose what you think is the right setting based on that. I ended up choosing .035 after a bunch of head scratching, but to be honest I probably could have gone one step in either direction. I printed another calibration cube with the new PA setting, and I did see some improvements around the corners.
The next step is to adjust the extrusion multiplier. This differs from the extruder calibration in that it is filament dependent. So if I changed brands, and sometimes even colors (or individual spools) of filament, in theory I might need to re-tune this setting. I had to tune the EM on my Prusa as well when printing the Bear parts, but the process that the designer of the Bear upgrade is different from what the Voron crowd follows. I'm not sure if one way is more correct than the other, but I think it might have as much to do with differences in how PETG and ABS behave, since the Bear is designed to be printed in PETG, while the Voron parts are ABS. I followed the Voron recommended process, which is more based on visual appearance, vs. the Bear procedure, which is based on actually measuring extrusion widths with a micrometer. When in Rome...
You print these little 30mmx30mmx3mm calibration cubes, at incrementally differing EM settings and then choose the one that has the upper surface the most like what you are looking for. I tried adjusting the brightness and shadow of the above photo to make it easier to see the differences between them, but I only had limited success at that. Anyway, the first square I printed was at an EM of .98, which was way overextruded based on the rough appearance of the top layer. Basically it's putting out too much plastic, and the nozzle makes ridges as it is dragging through it. I dropped to .94 and that was closer, and then printed another square at .92 and settled on that. Based on what I have read, that is a common extrusion multiplier to use with a Voron.
Currently it is printing a new calibration cube so I can see what total effect the changes have made. I know already that I will need to re-do the first layer calibration, which is normal after changing the EM, since now it is only extruding 92% of the plastic that it was before. I will probably do some printing with it like this, and then my next steps I think are going to be to re-adjust the belt tension (they loosen up for a while as the printer is used), and then run input shaping using the accelerometer that came with the kit.