I did some mesurements today concerning the nozzle temperatures.
I took a high temperature mesurment device (-50 - 1300 °C) and put it into boiling water and guess, it shows - exactly 100,0°C.
I placed it very near to the nozzle under the silicone wrapping with some termalpaste.
Then I heated the nozzle first in 50° the in 10° steps.
This is what I got
I let it at least for 1 houer there and I can not see it rise more than the 231 °C.
Not sure how precise my thermometer will be at 275 °C - at 100 it is!
Whats your opinion about the data?
I think you shouldn’t underestimate the potential temperature difference based on the location of the sensor. It’s probably not easily feasible, but if you would swap the locations of the thermistor and your measuring probe, you could validate if you see a similar delta, or just the other way around.
Or if you dip the SM thermistor in the same pot of boiling water as your measurement device, do you still see that delta?
Your right, these are no excat mesurments. But the original thermistor is not nearer to the nozzle as mine was, and sure there where differences but I never thought that there will be 40° difference.
Can you tell me where the temperature must be on point if not on the heatblock? At least after a hour.
@stefix Have you seen Calibrate Hot End Thermistor? The numbers there seem roughly similar… Anyway could you send me the table in a processable format, I want to do some curve fitting?
But it is embedded inside the part. Yours is “only” touching it and on a different location. So there is a real chance that the actual temperature is different. It only has to be a few mm further away from the heat source to have a measurable difference.
I agree that after an hour, the difference should be stable/minimal. But you are evaluating rather high temperatures compared to room temperature.
A typical full metal pot on your stove can be touched with bare hands on the handle and you burn your skin off when you touch the bottom
Will try to put the probe in the hole of the heatblock together with the original sensor. Lets see I will post the data when I have it. And metal pots are typicaly designd to do not transfer to much heat to their handels.
If you’re pulling the original one out, you could also just dip it in a glass of hot water together with the other one and see if the gap is smaller than you expect. (if you’'re water is
80-90 degrees and the SM claims it’s 100° you already know that the original difference was correct and you don’t have to bother further.
True, and I would hope that the heatblock and nozzle are also designed to transfer as much heat as possible to the filament, thus to the inside and less to the outside walls of the block
There is definitley a temparature discrepancy… see my thread. I was printing with Silk PLA which is very temparature sensitive in terms of keeping its silky finish. On all my other 8 duet wifi based properly calibrated printers the material loses its glossy silk finish if printed at much more than 205deg. I could print it at 250 deg C on my snapmaker and it was fine. And indeed printing at 195 on the snapmaker led to poor layer adhesion.
So its defo out somewhere. Ive got 4 different print heaters that i got when i got the snapmaker and all are the same. Ive bought a different 100k thermistor with 1% tolerance to fit instead as a quick thing to solve or eliminate an issue
This is basic stuff though that you would expect to be right from day one…
@stefix out of interest have you secured your thermisor with thermal paste or similar. As I wonder when snapmaker team first calibrated the tables… if they did it with a loose thermistor in the heater block… i.e. as supplied from factory then it wouldnt get as much heat transferred to it as it does with thermal paste/compound securing it and giving a much better heat transfer.
This might be the reason why snapmaker firmware temparature reported is now higher than actual?
@chazr33gtr Will have a look to that, but not sure I have one thats not prepared with termalpaste
Is nozzle calibration a doable thing on the snapmaker?
I had read that some of the things like pid tuning don’t work for it.
if it is doable, i would love to pull my hotend out, apply my boron nitride paste in there and do that calibration.
Missing thermal paste will only ever make the hot end run too hot. It’s not possible that missing paste can make the hot end run cool.
@clewis That were my toughts too!
@chazr33gtr But I testet now a couple of hotends. And I found that those one I have preped with thermalpaste go not over 240 °C while those without thermalpaste go up to 273°C.
Can anyone confirm this? Or do I something missing??
What are you doing setting the nozzle to max and letting it go as high as it can, and you are measuring a max temperature of 240? or is that what the snapmaker is reporting?
With thermalpaste I found the "real " nozzle temperatur at 243°C Snapmaker said 275 °C without 273 to 275 hmmmmm SM temps are out of Terminal. When I heat it outside the printhead, only elictrical connectet it goes up to 275.
@brvdboss I looked at the orignal thermistor, and it goes not halve the way in its hole, the cables are about 6mm to short.
Yes they are quite short.
Actually i had noticed on a newer one I had it appeared to be 1-2mm longer.
with that said, can we try to change the resistance value in the firmware to see if it will make the nozzle hotter? or is the hotend not going to get any hotter no matter what we do.
thats the question!
that and, i wonder if we can find a heatblock we can install somehow…
Have you tried to put thermal paste on the heatbreak and nozzle where they meet in the heatblock to see if that has any good impact?
I have noticed a similar delta between my measured and a brass nozzle. If you place a stainless tip on it the delta increases due stainless steel’s poor heat transfer. I believe that the thermocouple is where the ideal measurements should be taken.
I think your missing my point… if they calibrated the hot end table with a loose thermistor / poor heat transfer to the thermistor then the hot end would have to get much hotter than the temp they commanded to actually register the correct temp. Those values would then be stored in the thermistor table.
No do it with good thermal conductivity to the thermistor and it takes a lot less heat to show the same temparature!
This seems to be validated by @stefix test without thermal paste…
This is a problem. The average user (like me) does not have the skillset to tinker with the heating components. And if we try to follow tutorials where temperature is specified for different filaments, the projects could fail as as a result of this mismatch.