SunnyB

Hi everyone, First time 3D printer user here, we bought an UM3Ex for our lab, and I'm playing around with it, trying to see what is possible. I'm really loving it so far, thank you for this great poduct. However, I am repeatedly running into problems with PVA. It would not print very well, as sometimes it felt like the extrusion control was not great, so there would be PVA in places there shouldn't be. I have tried to clean the BB printcore as specified and when cold-pulling, my PLA filament looks like follows: There is an elongated section in the filament, as well as a part close to the tip that looks partly "shaved off". Is this supposed to look like that, or am I making a mistake during the maintenance? Additionally, the BB printhead looks burnt (shown in the picture below), and this is after only one print. I'm not sure if this is related to my issues with the PVA, but it does not look normal. Is there anything I can do to prevent this from happening? Thank you very much for all your help, SunnyB EDIT: One more thing. When unloading both print materials after print (silver PLA and tranparent PVA), the end of each filament looked quite different. PLA looked as I expected, but PVA had a very elongated, uneven tip. Once again, I'm not sure if this is something caused by erroneous handling on my part, normal, or a sign of a problem with the printer. Any help and information is greatly appreciated.