3D Printing: E3D Thermistor Alternative (2 Solutions!)
Channel: Roel Van de Paar
Date: 24/06/2019

3D Printing: E3D Thermistor Alternative


The Question: E3D hotends use a thermistor whose legs are insulated with glass fiber sleeving
and clamped down with a screw and washer:
[enter_image_description_here]
This solution enables the printing of high temperature materials, but it's a
bit fragile and after reassembling the hotend a couple of times, the screw will
have thoroughly mangled the thermistor's legs and sleeving.
Some knockoff E3D hotends use a (horrible) solution where the thermistor is
just loose in its respective hole, and kapton taped to the heater cartridge
wires which holds it in place:
[enter_image_description_here]
This solution seems kind of ad-hoc, and I'm worried about the thermistor coming
loose. One advantage is that it can be reassembled arbitrarily often, since
just pulling out the heater cartridge also pulls out the thermistor without
damaging it. Note that the picture shows PTFE sleeving which restricts the
temperature, but you could easily use fibreglass in this situation as well.
Another solution is the stud thermistor:
[enter_image_description_here]
It screws into the hole that is normally used for the clamping screw.
Unfortunately you're limited to around 250C because of the epoxy used in the
stud. I've also found that the epoxy fails after a while (regardless of
temperature) and the thermistor isn't locked in place any more (it still works,
by virtue of being constrained by the heater cartridge wires as in the previous
solution but that's not ideal).
Are there any solutions, compatible with genuine E3D hotends, that:
 * are not limited in temperature by epoxy or PTFE,
 * can withstand being disassembled and reassembled better than the standard
 fiberglass sleeving,
 * is a bit less hokey than a kapton taping the thermistor's wires to the
 heater cartridge and hoping that holds it in place?

Solutions Sample (Please watch the whole video to see all solutions, in order of how many people found them helpful)

== This solution helped 2 people ==
I like the mounting method on my Mk9 extruder: there's a small hole drilled
into the heat block, parallel to the heater hole. B3 Innovations sells a
thermistor packaged into a small spring. The whole assembly goes in the hole,
and a setscrew (gently!) secures it. You could just as well put a bare
thermistor into a spring or something similar; it's mainly to protect the
thermistor from the setscrew, and from excessive bending.
From your photo, it looks like the same thing would work fine for your hotend.
However you mount it, adding some thermal grease can help conduction from the
surroundings.

With thanks & praise to God, and with thanks to the many people who have made this project possible! | Content (except music & images) licensed under cc by-sa 3.0 | Music: https://www.bensound.com/royalty-free-music | Images: https://stocksnap.io/license & others | With thanks to user vittorio88 (https://askubuntu.com/users/13462), user Tom van der Zanden (https://askubuntu.com/users/26), user TextGeek (https://askubuntu.com/users/40), and the Stack Exchange Network (https://3dprinting.stackexchange.com/questions/293). Trademarks are property of their respective owners. Disclaimer: All information is provided "AS IS" without warranty of any kind. You are responsible for your own actions. Please contact me if anything is amiss at Roel D.OT VandePaar A.T gmail.com.