Hi Folks,
Was wondering what everyone’s experience is with Glow in the Dark, Wood and Carbon Fiber Filament? I have some spare harden nozzles arriving too. I read that they are really abrasive and just want to be prepared. Also, is changing the nozzle fairly simple? Any advice and cautions would be appreciated! Thanks!
I guess what I’m about to say is debated amongst some people, but there is an objectively correct way to assemble the nozzle / heat block / heat break assembly, and from the factory some hot ends are assembled wrong.
The nozzle should bottom out against the heat break, not the heat block. From the factory, the nozzle is occasionally screwed all the way against the block, which can in some circumstances result in oozing filament leaking out of the spiral thread leakage path.
What @brent113 said.
Also you will need to heat up the nozzle to unscrew it. A socket works best so you won’t damage it. A wrench is fine too. Just don’t use pliers or vise grips or you’ll probably deform it.
I’ve only printed with glow in the dark. I used the standard nozzle since I figured I was close to wanting to change it anyway. Didn’t find that it caused any wear that I could see, but I didn’t print that much stuff.
I think every filament is different though. I know that some wood filaments don’t actually contain any wood and some have less than others. I know a couple people who they did wear out the nozzle noticeably after only 3 or 4 medium sized prints.
I would check with the filament manufacturer. They usually have info on whether you need a hardened nozzle. They aren’t particularly expensive (unless you’re splurging for something like an Olson Ruby) so it’s not a big deal to swap out one.
You may need to up the nozzle temperature because the hardened material may not transmit heat as efficiently.
-S
I recently bought a couple of Tungzzle nozzles (The Ultimate Tungzzle - The 3D Printing Tungsten Nozzle by 3D Hex — Kickstarter) for printing abrasive filament. Not cheap, but they should be ideal, as tungsten is a much better conductor of heat than coated brass, stainless steel etc and has very low wear. The only thing stopping me at the moment is concern about the impact of abrasive filament on the extruder gear. 
I can speak to the use of carbon fiber imbedded PLA filament from Sunlu/Suntop/Ziro3D/Protopasta (Hi-Temp Carbon Fibre) printing with the SM2 A350.
I’ve had excellent results with functional parts printed at 215°C/60-80°C (the higher carbon fiber content adheres better to a warmer bed, especially when using chopped carbon imbedded fiber, as found in most inexpensive filament), with less edge lift on larger prints as well.
As for the abrasive nature of these filaments and associated print nozzle wear, I typically push the head until I just barely note a degradation to the initial raft layer as I initiate a print job. This seems to occur after a little more than 80 hours of printing time logged (on average) using an inexpensive Chinese brass 0.4 nozzle. I have not noticed any loss of quality or layer adhesion prior to this number of hours logged per nozzle in the last 1 1/2 years of daily use of my SM2 A350.
(I purchase the above filaments from Amazon; pricing and availability being the biggest drivers here.)
Hope this is of some help.
I just use brass nozzles for carbon fiber and toss them once they start to wear out usually after about a half of a roll of filament