Hello, had an idea that I wanted to think out with the community before potentially attempting: Thermal interface material (thermal paste/grease) between the nozzle and heater assembly on the H2D. My thinking is, the heater and thermistor are separate from the nozzle on this printer series, and it appears that the thermistor is reading the temperature of the mounting plate for the nozzle rather than the nozzle itself. Given that the mounting interfaces aren’t exactly atomically smooth, I suspect there’s room for a pretty significant thermal gradient between the nozzle itself and the nozzle mount, especially when printing at high speeds.
Basic testing of this seems like it would be pretty straightforward, with no modifications required to printer hardware. Basically, tape a thermistor to the mount and another to the nozzle face, then ramp up the nozzle temperature to 300C and log the temperatures over time and note any difference between the two sensors. Might be possible to get a rough idea with a good thermal camera as well.
Better testing I think would require modifying a nozzle body to house a sensor (drill a hole in it) to get a more accurate reading, plus running wiring out the top of the printer so an actual print job could be run while logging.
If the testing does show a significant difference between the base and nozzle and especially if it shows the nozzle below the set temperature, then moving onto using a high-quality thermal paste application and retesting would make sense.
I know I’m making a bunch of assumptions with this idea.
I know what a massive difference thermal interface material makes in the computer cooling world, and the metal surfaces on the nozzles and mounting plates are downright rough compared to even mid-tier CPU coolers that still completely fail without thermal grease. I’m assuming that the nozzle temperature fluctuating 5-10 degrees while running a print job could potentially result in a fluidity difference big enough to cause failure when running close to the upper bounds of a filament’s speed range.
Just want to throw this out there. The printer is calibrated to take into account the heat block and how it varies from the nozzle.
The thermal grease used or even more advanced stuff is more than enough for the thermistor to heat block mating.
One of my many many assumptions is that the printer uses PID control to maintain the temperature, but I didn’t think of there being a manual “crappy interface” adjustment coded in to account for the nozzle itself being so poorly mated to the heat block.
No argument on however the factory thermistor is mounted and interfaced. You’ve raised the question in my mind though: Is it reporting actual mount temperature, or an adjusted nozzle temperature to account for thermal lag?
Im using Weicon Anti-Seize, closes airgaps, hinders filament from wandering up the nozzle seat and eases cleaning of the nozzle body upper of the nozzle.
Since i started using this on the H2D, i also started using it on the P1S Ceramic Heater Element and thermistor instead of thermal grease wich turns into cement after 500 hours. Works great, makes service way better, doesnt change anything in the process im printing just like before. But need to be set to 300°C while airing the room since it is “smoking” slightly at first heat. Its rated for 1200°C
Try pointing a heat gun at your nozzle after heating it up if it reads correct I personally wouldn’t give it a second thought.
I hadn’t thought of an interface material preventing filament from getting in there, but that makes sense. I’ve had that happen on two separate occasions and it required removing the nozzle at high temperature and fiddly cleaning of the mating surfaces with a brush, so that sounds like a good advantage. That anti-seize has pretty bad thermal conductivity as compared to traditional thermal paste, but it’s still better than an air gap. Thanks for the product name; I’ll keep it in mind.
No offense, but I think you’re trying to find a solution and a problem.
The degree variant between nozzle tip and where the heat is is going to be negligible. They are close together and the material used is conductive well enough to prevent enough of that variation to matter. In addition today’s printer software is more than capable of keeping the nozzle at the right temp for the material used. Otherwise there would be evidence throughout the user base to show a problem.
I mean, do it if you want. I wouldn’t bother with a printer, simply set up an extruder/heater on a test bench and measure. Maybe put a cardboard or flame retardant material (safety 3rd) to eliminate breezes. You could simply use a V6 nozzle of varying materials.
Or you could YouTube it. Your choice.
Yeah, I think you’re right. The only potential advantage I can see is the anti-seize property, but I don’t death-blob my printer on the regular, so that’s minimal as well. Not to mention, I swap nozzles about every five minutes it seems. Would get messy and expensive.
Might be a moot point on the H2D anyway. Looking at the heatblock and nozzle interface closer, they’ve mounted the thermistor in such a way that it primarily senses the lower end of the mounted nozzle itself rather than the heater. So… think they thunk this already. 
Well if you get a blob the best weapon is heat. Just reheat and pull what you can off. Then apply heat and remove as much material as you can using plastic scrapers or brass brushes.
The current printer and to some extent the X and P1 series work the same way. You just either have to realize the thermistor and/or heater are gone or just be careful.