Temperature readings....

I did some tests with an external thermistor and multimeter to check how accurate my hotends work.
Reason for the hassle was the fact that after changing to a new hotend but using my trusted thermistors I needed much higher print temps to get proper layer bonding.
Bridging was a nightmare too...
On all my previous hotends I modified the nozzle to cater for the thermistor right where the action happens.
This E3D clone has the thermistor inside the heater block.
From nozzle temp to the temp read by the hotend thermistor is a difference of almost 10°C!
Keeping tolerances in mind it might be good to know for some that the actual nozzle temp must not always match what the temp reading suggests.

Same is true for the temp suggestions you see on the seller's website.
They don't specify if it is the nozzle temp or not, they just "wobble" around the actual temp.
So if the filament works best at 197°C they will take the tolerances and differences from thermistor location into account and state 185-210°C.

I started now to add stickers onto my filament rolls, stating the last used print profile and temp settings, plus what nozzle type was used.

The fan attachment also has a huge influence on temp readings.
Those e3d clones don´t have a fan shroud and the heater block isn´t insulated. Airflow across the heaterblock can spoil the whole PID setting caused by faulty temp readout.
-Olaf

I own the original E3D v6 hot end and have a thermo couple instead of an NTC. I also own a digital volt meter with thermo couple. When I put the DVM thermo couple in the cold end right down to the nozzle, the temperature that's measured with the DVM is about 2 degrees lower than the thermo couple read out of the hot end. That's within the error margin of thermo couples. Make sure the nozzle is screwed in tight enough into the heater block.

I use no insulation of the heater block, but I use a custom hot end holder with fan shroud. The fan runs at a very low speed though, and provides plenty of cooling.

I think that many users run their fans at full speed which will have an impact on how well the heater block heats the nozzle. At full speed I'm having trouble reaching 285 degrees.

I also added a shroud on the opposite side of the fan (facing away from the hot end) to prevent air from reaching the hot end and printed part. The fan actually stalls a bit, hence some of the air escapes on the 'wrong' side.

Hmm, I have no issues at all with the hotend fan at full power.
Even when printing Nylon no problem reaching and keeping the right temp.
Heater block is not insulated here but I used thermal plaster to glue it in place instad of the jamming by the set screw.
Funny thing is that even at Nylon temps, close to the safety area of the thermistor, the cold end stays cool in the top part and only about the fist 3 fins at the bottom heat up.
The only thing affecting my nozzle temp is a sudden drop in the outside temp, like when opening a window to let the fumes out.
But even then it only fluctuates down by less than 5 degrees and stabilises within a minute.

With an uninsulated hotend, I wonder how much influence the XY-feedrate has on temp-stability?
A very fast ( delta ) printer would move the effector so fast, it could almost extinguish a match

( would be a nice challenge )
-Olaf

I did some tests on that one when I wanted to check the max speed my printer can do before it rattles apart.
No surpise PLA with low temp did best and only failed at around 160mm/s as there was not enough time to make a properly fused contact I think.
Temp was set to 240° for this and I tested with a solid infill pattern, same for the other materials except the temp
Using ABS the temp still was stable and only fluctuated within 3°C.
Tested with a max of 90mm/s @ 265°.
I think the heater block is doing a good job of retaining enough heat for the changes in the filament speed.
Although with my extra slim and directly heated nozzle I have even better results in terms of temp stability but it is pain to do the PID tuning for higher temps as it heats and cools extremly fast.
If I ever find enough spare time I will make a few more nozzles and check if I can modify the Marlin code for faster temp checks.