I had been changing the filament or changing the nozzles in my E3D-v6 Hot end without problems.
Nevertheless, In the last changes I have experienced obstructions with filament waste
between the Wades block and the Hod end in the step of extracting the filament.
After some tests, varying temperature (185-230), or velocity of reverse extrusion (50-150 mm/min)
I found that a critical factor was the velocity. At 50 mm/min I can extract the filament without any filament
remaining besides the extracted filament with the form that is shown in the attached picture.
If anyone have other values, parameters or procedures to change filament or nozzles, I would appreciate to know about them.
Thanks for reading