Wrong Nozzle Size for 3 Years on Kittaz

First things first, my Kittaz is awesome. I’ve printed well over 2000 hours worth of good looking production parts on this printer. Over the course of that time I’ve had my share of breakdowns or issues like blown heater resistors and broken teeth on the small herringbone gear, but only recently in the last 500 hours or so have I started to have clogged nozzles. While attempting to clear one such clog I messed up the nozzle, which caused the parts to print poorly.

So I order a replacement nozzle, a 0.35mm nozzle like all Kittaz and Taz 4s came with. Comparing it to the old nozzle it looks a bit smaller, and when manually extruding the pipe of filament comes out smaller than I remember… Furthermore it seems to print parts with the gcode I’ve always used a bit differently…

My old nozzle had a 0.50 on the side. However, Kittaz and Taz 4 always had .35mm nozzles stock. Heck, lulzbot doesn’t even publish slicr profiles for a 0.5mm nozzle.

So apparently I’ve been printing with a 0.5mm nozzle for the last 3 years, while generating Gcode for a 0.35mm nozzle.

I honestly couldn’t care less except that the 25+ parts that I have in production will all need to be printed once, resized for fitment, and then reprinted once more for confirmation before I can print them in quantity again…

The only good to come of this is that I’m using the opportunity to switch to the hexagon hotend with a 0.5mm nozzle, which requires slight refitting of the parts as well. I’m hoping that the supposed faster printing with a larger nozzle is something that is more than just theoretical…

This has been a very educational few days!

I’ve been impressed with the new Hexagon hot end since the parts have better layer adhesion, however, the top surface is very rough.

I tried reducing the flow, thinner layers, slower printing, reducing the extruder temp, and nothing seemed to work. Out of desperation I went back to Slicr and used the 0.35mm nozzle with the new Hexagon hot end that has a 0.5mm nozzle. The print turned out great!

At this point I discovered a few things:

  1. The nozzle size has the most effect on the largest line width you can print with. You can easily print with a smaller line width than the maximum.
  2. Slicr allows you to specify the line width for top layers.
  3. Finer top layers result in MUCH better top layer surface finish.

So what was happening over the last 3 years was that I was benefiting from using a maximum line width for a 0.35mm nozzle, even though I could have had a line width up to the max for a 0.5mm nozzle. When I started using a 0.5mm nozzle profile I ended up with drastically faster prints, but much worse surface finishes.

By using a 0.5mm nozzle profile, and using Slicr to reduce the top layer line width I can get drastically faster prints with good surface finish (one print went from 10 hours to 5 hours).

Is there an equivalent setting to the top layer infill width of Slicr in Cura?