Temperature drop while printing

Controllers Smoothie
1

Hey all im wondering if anyone can help me figure out what would make sense todo next. I am seeing a 3-7 degree drop in temperature while printing which varies depending on the model it seems. Setup consists of an E3D volcano with .8 nozzle on smoothieware at 1800mm/min with 2 blower fans cooling the print and an E3D fan cooling the nozzle, 40W heater cartridge

What ive done
-PID autotune: I have done an autotune with blowers on at full blast giving me P41.0 I2.615 D161
-Hotend is insulated with heatsleeving and kapton tape
-Using a E3D cartidge thermistor (assuming that this has exactly the same profile as the old style E3D thermistor as that’s what its enabled as in the smoothieware configuration right now, not using a beta value)
-Slowing down the print: even at 1800mm/min, .6 layer height and .8 layer width (19.2mm3/sec) which is a lot lower then the possible 45mm3/s

Imported from wikidot

2

0.8mm nozzle means you are pushing an unusually large amount of plastic through. Cold plastic. That could just be it.
Simple solution is just set your temperature a bit higher …

3

The thing is other users are able to push higher volumes of plastic without this issue. Moving my temperature higher might be a decent idea but if there is fluctuation still it will still cause odd layer aesthetics. Do you think reducing my P value would help?

4

I’m really bad at pid tuning, but there are *a lot* of guides on the internet, and they should all apply to smoothie as-is.

5

Fair enough, I’ve got some reading ahead of me. One more question though, should marlins pid produce similar results to smoothies? Or are the algorithms different?

6

Nope, different.