There is a long thread about the
PID-regulation of the heated bed on UM2 and banding here:
https://ultimaker.com/en/community/7907 ... um2?page=2
In short words, the bed heating used to use fast switching
PID-regulation but EMC-certification issues (too much radio noise) forced Ultimaker to change to an on/off regulation known as "
bang-
bang"-mode.
It quickly turned out that for some reason the new
bang-
bang-mode induced banding on the printed objects, just downgrading to an old
PID-firmware increased printing quality a lot.
(Maybe we should create a separate thread about this?)