Hi,
I followed the tutorial here:
https://wiki.e3d-online.com/wiki/E3D-v6_on_Ultimaker_2
And installed a E3D extruder on my UM2. It's also in a direct extrusion configuration (mounted directly on the printhead).
I modified the firmware as instructed, nothing fancy, from the official Marlin firmware:
https://github.com/Ultimaker/Ultimaker2Marlin
I didn't do anything exotic. Everything works perfectly, I can print normaly, change material, etc, but I have one concern:
During the reversing of material (when I want to change material), the extruder reverses a certain amount of filament fast (it lasts for ~3 seconds), then slows down (~3 seconds), then reverses fast again (~3 seconds), and so on. The sequence is repeated a few times.
It wasn't like that before I flashed the new firmware (but the firmware of my UM2 was never updated before, it's quite old).
Is it normal ?