Thermistors in Rumba? The thermistor that came with the e3d was a casualty of

(Mike Miller) #1

Thermistors in Rumba?

The thermistor that came with the e3d was a casualty of the Great-Filament-Blob incident of 2014…I couldn’t extricate it from the mess of kapton and filament…but I had, like, 5 thermistors included in the Rumba deluxe kit I bought from RepRapDiscount. I’m using “5 is 100K thermistor - ATC Semitec 104GT-2” and it’s kinda in the ballpark…kinda. After multiple PID calibrations, there’s still a lot of hunting to get the right temp.

The other possibility is that it’s slightly too far from the heater, the Thermistor is a larger diameter than the e3d part, and rather than take a drastic step I couldn’t back off from (making the thermistor hole larger), I used the other hole that’s drilled through the block that’s normally unused.

(William Frick) #2

Does the thermistor have intimate contact with the block ? I also found vaying PID results with different target temps. Pick a temp close to what you normally use. Alternately try different thermistor types from the table. I run a G-Code prefix setting the PID values from the different Auto Tune runs, each one generated from different target temps.

(Mike Miller) #3

Any more intimate and it’d be meeting the family and setting a wedding date…but there’s no thermal compound or anything for the mating surfaces. Its not greatly affecting prints, though you can see the thermal changes in the surface quality (not important right now, I’m not printing dust catchers)… But I have to manually unclog for every print now and I suspect this is the reason.

(Sanjay Mortimer) #4

The thermistors we supply are #5 in marlin, the ones Elvira from RRD supplies are #1 EPCOS thermistors (Or very similar clones). So that is probably the root cause of your temperature miscalibration.

(Mike Miller) #5

This is an unlabelled thermistor that was sent with my RUMBA controller. The e3d one was destroyed in a horrible industrial accident for which I take full responsibility.

(William Frick) #6

@Mike_Miller Why does the 'Great Filament-Blob Incident ’ sound like the synopsis for a “B” grade horror/sci-fi flic ?

(Mike Miller) #7

Well, by the time the yellow pla started to cook a little, it DID look like a snot monster.