E3D-V6 thermistor

[bbrown64]

I seem to be consuming a few thermistors. Once in a while my E3D-V6 will act up and not heat up. I traced it to the thermistor not telling the software what temp the hot end is. I get a 357 error in Cura. I replace the thermistor and the error goes away and the hotend works.

My question is this: Is there anything more robust that can be used in place of those tiny/fragile thermistors?

[Mooselake]

How are they failing? Are the wires breaking off? Iirc this was discussed a while back, and the fix was to add some support to the wiring.

Kirk

[RetireeJay]

When the thermistor fails, what temperature does it read? These are Negative Temperature Coefficient devices, so a reading of an extremely high temperature indicates a short circuit. Like maybe both leads of the thermistor are touching the aluminum body, shorting out the thermistor. In that case, the solution is very simple: add more Kapton tape to insulate the leads. If there is a broken wire, the resistance will be infinite, which looks like an extremely cold temperature to the Printrboard. That could be harder to fix, depending on where the break is. Anywhere that wires flex is a potential for breakage. The tighter the bending radius and the more frequently the wire bends, the sooner it will break. The break could be in the copper wires leading up to the thermistor leads.

As Mooselake said, you definitely want to keep the thermistor leads themselves from flexing. I try to minimize how much I flex them during installation, and I secure them in a way that they don't flex AT ALL during operation.

[bbrown64]

The thermistor wires are ty rapped to the heater cartridge wires. There is no movement in the wires. I suspect the tiny wires very near the glass bulb maybe touch the heater block. What I am looking for is something more robust than those tiny thermistor. I particularly do no like having to deal with those whisker thin wires. Usually I have to replace the thermistor after the hotend has been moved while printing. This is a failure of the lower part of the extruder not being able to get but 2mm of the cooling fins to clamp to. I know there has got to be a better way to tell the software how hot the hotend is getting, so it can be regulated.

[thawkins]

[evanalmighty]

You should post a picture of your hotend install and how the thermistor is placed/fixed in place. Thermistors are thin/fragile, but I haven't managed to break any with the exception of the original Printrbot one. That was a piece.

[RetireeJay]

There's got to be a better way of mounting the extruder than with only 2mm of insertion to grab onto! That is your problem; fix it, and the thermistor problem will be solved too.

[bbrown64]

Jay, I think you have the correct idea. I just need a 3/16" piece of machined flat aluminum, or borosilicate glass. I have already moved the heated bed on top of the side rails. Once I get that done. I will no longer need the spacer that is on top of the E3D-V6. I have already machined down the top fin of the E3D-V6 so it misses the mounting screws for the extruder.
I like the idea of a bit of PTFE wrapped around the wire leads to help insulate them from the hot end. All good suggestions thank you everyone.