Third independent thermistor? [Marlin / RAMPS / Repetier]

Hi all!

I have had some breakdowns (heat-creep most probably) in my E3D v6 bowden, and it's probably one or several of these reasons: too much retraction, too slow print, old filament and bad cooling of the heat-sink (my bad design and a very low noise fan).
So as I'm waiting for some new filament, I thought it would be nice to monitor the heat break temperature (or close to it, like on the first slice of the heat sink) to see how things are going at different speeds, temperatures, over time and so on and after some searching it seems that the RAMPS board has 3 entries for thermistors!

But the only thing I have found about more thermistors and Marlin, is that it can be used as a back up for the hot end one...

My setup is based on Marlin, RAMPS and Repetier, is there a chance I would get a graph in Repetier like for the heatbed and the hot end?
Or just an M-command?

Any pointers greatly appreciated!

A common problem with the clone e3d v5 and v6 is the fans supplied are not acceptable.
You need at least 5cfm of air on that little 30mm fan to make the heat brake do its job. Get a high RPM BB 30mm fan on that..... here is the one I put on and it cools great:
[www.aliexpress.com]
I use it on this fan shroud assembly that I printed with ABS for better heat resistance:
[www.thingiverse.com]

The setup needed a silicone sock tho as it was cooling my hotend temp too much. [www.thingiverse.com]

if you really want to monitor the temp tho maybe better than using the Ramps maybe get an el-cheapo temp probe.
I think your unlikely to worry about this after you work out the issue and correct it.

Temp probe

Edited 3 time(s). Last edit at 10/17/2017 02:36PM by JustSumGuy.

Hey I just saw this and thought of your issue....

[www.youtube.com]

instead of a loud fan on the heatbrake how about water cooled!!

Hey thanks!

I actually have exactly that fan in the thingiverse picture (Noctua 40x40)! It does 5.88cfm IIRC but I guess it's hampered by my ugly attachment, this one looks much better.
I put back the original fan I got with the E3D (I bought a clone first but I broke the heat break and couldn't get it back up and running without problems so I bought a "real" one) and it came with a silicon sock, didn't know it's use was also to keep the hotend protected from a print-fan!

I didn't know temp probes were that cheap, seriously O_o, will buy one and forget about integrating it in Marlin/Repetier, thanks, solves my issue!

For the water cooling, I'm actually working on a similar concept (so a second use for temperature probing) but as I have a CoreXY Bowden setup I wouldn't like a heavy water tank sploshing around at high speed (maybe I don't need That much water though...), so I thought that I do it with air instead. We'll see how it pans out...

Happy to help

too bad Noctua does not make a 30mm high air fan....

the noise from my 30mm heatbrake fan is annoying....

I am thinking of this water cooling now because of it....

Edited 1 time(s). Last edit at 10/18/2017 11:37AM by JustSumGuy.