I ended up typing a lot more than I expected to...
I have a Tevo Little Monster I've converted to Duet/RRF, with a Volcano nozzle & Bondtech extruder. I've used every nozzle on it from .4 to 1.2mm. I've always gone by the rule of thumb that a standard hotblock can output a volume of plastic about 10cubic mm/sec , while the volcano can do around 30cubic mm/sec (the flowrate). And like mentioned above, it's the volume of plastic you're pushing that makes the print go fast, not how fast the toolhead moves. I've done testing to push those limits, and they seem to be a pretty good rule of thumb: Even if your extruder is strong enough to push more plastic in there (and the Bondtech is good at that), at a certain point the heater can't keep up (more cold pastic is moving in than it can heat up in time), and you get temp drop, and a filament jam. You can compensate by running even higher temps (say, print your PLA at 250c), but it's a dangerous game, I've tried for testing purposes, not recommended.
So with a 1.2mm nozzle (with a 1.2mm extrusion width), you can print 900 micron layers at 27mm/sec (.9 * 23 * 1.2 = 29.16), or you could print 300 micron layers at 83mm/sec and still hit the 30mm3/sec (.3 * 83 * 1.2 = 29.88) flowrate, and technically (based on your acceleration & jerk values) the'd both have the same overall print time.
I've found thin\thick layers both have some advantages\disadvantages compared to each other:
- The lower your layer height, the better you can do overhangs, since you have more 'steps' to print on below each layer. And the layers cool faster which can matter.
- But since the big fat layers have to be printed at a slower speed, it really mitigates out any speed related artifact like XY ringing, and technically you're getting a stronger bond simply because you have fewer layers being glued together : On my core-xy (RADDS/RRF), I have a crazy powerful ducted fan specifically designed to cool down big layers, since that residual heat is very easy to build up.
My TLM shipped with a knockoff Titan. I use a Bondtech on my other core-xy : I very quickly bought another Bondtech for the TLM. Bondtech is great, especially when you're trying to squeeze large amounts of filament into the nozzle: The dual hobbed-gears in there are the clear winner compared to a spring pressing against an idler.
Also, there are 3 main differences between the volcano and standard e3d v6 hotend:
- Bigger nozzle orifices (although you can run any size you want, I'm currently running a .4 on my corexy volcano)
- Bigger hotblock: Physically more metal.
- Higher wattage heater cartridge: When I bought my first volcano, they accidentally sent me the heater cartridge for a standard hotend, and I couldn't figure out why I couldn't print at the flowrates described above: After checking the resistance on it, I realized it was under-powered: I got the correct wattage cartridge, and everything started to work as it should...
So if you go with a 'normal' v6 and decide to upgrade to a volcano, you need to replace all 3 of the above.
The only main downside I've seen is they have a larger melt-zone, and thus are more prone to stringing/oozing/blobbing, and you need to be a lot more aggressive with your retractions.