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anton.k
(@anton-k)
Active Member
Need help verifying heatsink temperature

So ... I'm still debugging my clogging / filament stripping. Removing the enclosure and lowering retraction settings didn't fix it after all.
I'm currently suspecting heat creeping up the extruder. Can somebody please verify my temperature readings? E3D v6 docs say heatsink should be "cool to the touch". My Laser thermometer says it ain't so.
Printing PLA, during the first layer I see about 145 C on the lowest fin. The temperature drops 10-20 degrees for the following layers. The center of the heatsink easily reads 60-80C
Is this expected?

Posted : 03/09/2017 5:28 pm
henrik.w
(@henrik-w)
Estimable Member
Re: Need help verifying heatsink temperature

Hello Anton!

Is the fan that cools the extruder on all the time the extruder is above 50 degrees C?

/Henrik

Posted : 03/09/2017 8:47 pm
aaron.s5
(@aaron-s5)
Noble Member
Re: Need help verifying heatsink temperature

First, laser thermometers are notorious for mis-reading temperatures on reflective things, but those values are WAY to high.

If the heat break gets above 40C or so you will get clogs.

I presume the extruder fan (on the opposite side of your photo) is running? and you can feel the air flow exiting by the PINDA sensor? Yes, the one that should always be on over 50C.

Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage or loss. If you solve your problem, please post the solution…

Posted : 03/09/2017 11:43 pm
JeffJordan
(@jeffjordan)
Moderator
Re: Need help verifying heatsink temperature

first a few words about "laser thermometers".
some people think that the laser beam really measures something... that's a common misbelieve, stimulated by advertisement... and completely wrong.
the process of temperature measurement is done by a small, infrared sensible chip.... sometimes with a simple infrared sensitive diode.
the laser only is a pointer, that should indicate the spot where the focus for the measurement should be located.

I've the same infrared thermometer with laser from amazon. its a real guessing-iron.

laser and measured spot only match at approx. 1m and more. at such a short distance they are way off.
so what you are measuring is most likely a part of the hotend instead of the coldend body.

one easy way to get an exact measurement of the coldends temperature is to clamp a thermistor between the lower fins of the coldend and measure the temperature through its resistance.
most of the multimeters that you can buy nowadays come along with such a thermistor and they even provide the proper temperature measurement range for the thermistor.

more expensive would be to measure it with a real infrared camera (pyrometre / bolometre).

dem inscheniör is' nix zu schwör...

Posted : 04/09/2017 12:35 am
walter.v4
(@walter-v4)
Active Member
Re: Need help verifying heatsink temperature

I agree with aaron.s5 and JeffJordan regarding these devices. As it appears I have such a thermometer, I went on and measured the temp. on the same spot as anton.k. I get around 35°C when ready to extrude. The temp. bed is pretty close to what I can see on the Prusa LCD display.

Anyway, I bought it to measure the temp on my walls to find out if there is humidity in the corners.

Posted : 04/09/2017 11:39 pm
JeffJordan
(@jeffjordan)
Moderator
Re: Need help verifying heatsink temperature


...I went on and measured the temp. on the same spot as anton.k. I get around 35°C when ready to extrude. ...

that's how it should be. I did the same thing at the i3 clone I build, while measuring with a thermistor, clamped between the fins of the coldend (as mentioned above), just to check if there is a difference when the extruder fan is reversed in direction (-> no difference).
got about 38°C here.

dem inscheniör is' nix zu schwör...

Posted : 04/09/2017 11:57 pm
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