Anyone have any tips or advice on validating the temp at the hot end?
I’ve been looking around online and see a little here and there about measuring the thermistor but was looking for something to validate my Printrbot Simple. I’m still having weird extrusion issues where it seems like the extrusion is not consistently flowing.
I’ve taken everything apart, cleaned, etc. but I’m wondering if I’m not getting accurate temps. I’m about to just buy another ubis head to swap it out.
An actual thermocouple probe would be the best but in a pinch I have used a digital kitchen thermometer. The key is to stick the probe inside the hot end and to test at a temp that does not break your thermometer.
Licking is contra-indicated.
Get a thermocouple probe that attaches to a multimeter. Most good multimeters can just accept a Type K out of the box.
If you get a nice steel rod type one you can slide it right down into the hotend where the filament would go and get actual internal nozzle temps.
Thanks for the feedback and I’ll look into the thermocouple probe. I have an IR thermometer but temps were all over the place with that so I knew it was a waste of time.
Something important to consider is that the heat has to have time to transfer to the filament. The faster the filament goes through the nozzle, the higher the temperature has to be to get the same amount of heat transfer per identical length of filament.
Ditto on using a type K thermocouple.
IR types aren’t much good on metal as the emissivity varies widely based on the material and finish.
You can improve the accuracy by covering the part with black hi-temp stove paint or heat-shrink tubing. You still have to deal with temperature averaging over the field of view of the sensor (typically ~30deg cone angle).
@NathanielStenzel , yup and agree. I’d done both where I’d raised the temp and lowered the speed. I know that they usually go hand in hand from the perspective if you increase speed then raise temp, but I was just trying to get back to a good level of extrusion.
I get the feeling that people only care that their temperature readings stay at a certain offset from the actual temperature unless they wish to compare to others. In other words, if a temp reads 78 instead of 75 and 233 instead of 230, it is fine as long as the reading is always 3 higher than reality.
@Tim_Sills what about using one of those laser thermal reader?
@Andre_Courchesne1 , yup, I’ve got one but I don’t think the footprint of its measuring surface is small enough to give it a precise measurement. As I move it around the head the measurements are inconsistent and none seem to reflect anywhere near what the head is set to.
@Tim_Sills Then my next suggestion as the others would be a K-type thermocouple like this one: https://www.adafruit.com/products/270
Quite easy to hook up to an Arduino
Type tm902c into ebay.
Nice one @Billy , it’s dirt cheap. Have you tried this and does it fit within the hot end or do you probe just the outside tip with it? Looks like the wire thickness may not allow you to slip it down into the hot end.
I have one. It works with the probes it ships with on a 3mm hotend. For a 1.75 you’d have to find another probe.