Hi all!
Moved from http://umforum.ultimaker.com/index.php?/topic/8160-nozzle-temperature-range-while-printing-910-degree-celsius/, klausz and I had the same problem, he decided to carry on here to avoid double posting.
In my case, this temp issue caused periodic wavy walls, especially on small spiralized prints.
After applying the heat conductive paste, this happened:
Yes, my mouth is still open too... Temp varies now +/- 1°! (Before +/- 10°)
Since I received my UM2 three months ago, I printed quite some things, some came out better, some not. Learned a lot about all the beautiful parameters, prints getting better. (Learned the most around here, of course!)
At the moment I´m experimenting with the spiralize option and get this cute wash board surface.
Did a little research and found different things.
I must confess that I noticed the high amplitude of the nozzle temp before, thought that´s probably state of the art and I have to deal with it. Harrumph. Sorry for that.
Although I´m terribly happy with the improvement through the heat paste, some questions arose:
Since the thermal feedback between heater and sensor is obviously so much better with this paste, why do we find these little boors completely naked in the nozzle block?
That leads directly to the next question:
Is the software meant and able to deal with at least a little insonsistency?
I think yes, but some people discovered difficulties with the last firmware updates http://umforum.ultimaker.com/index.php?/topic/6613-firmware-surface-kwality-bug-1407-vs-1403/?hl=%20horizontal%20%20banding.
This is a little test print I made while following the software trail on my research:
Compared Cura 14.07 to 14.10 before applying heat paste.
(To add a little confusion, firmware on printer is 14.09, but Cura 14.09 had a little bug in spiralize, which Daid fixed. Thanks, Daid!)
So as you see, there is an improvement. The gcode provided from 14.10 seems a little smarter in handling the big temp amplitude. But if this amplitude is already minimized on the hardware side, the result would be even better, wouldn´t it?
Looking at bigger, more complicated models with infill and all that, a permanent temp fluctuation will be compensated.
If several peaks happen inside one single layer, the outside walls may look straight.
Or the walls show an irregular horizontal banding, and that, as we all know, leads us to a wild wide variety of possible reasons including belts and axes, vibration etc. Sure, all of this has to be checked.
But I wonder why this thermal feedback issue is not more common?
Or is the heat paste more common than I thought?
Would love to have some feedback on my thougts, if anything is nebulous, don´t hesitate to ask.
@klausz: I hope this works for you, too. Fingers still crossed, please report!