V3 Hotend, rotating head

[fluxline 0]

So I've installed the V3 hotend and have had not stop grinding of filament. A couple things I've noticed are a) the entire hotend, brass/aluminium block/PEEK rotates easily by hand. Does not seem to move when printing but it freely rotates of you twist by hand. Is this supposed to be this way? The four head bolts are snug and there are no big gaps, there is one at the front right corner like before but in measuring the 'head' of the PEEK is higher than the stubs on the alum block so it must be have a little gap.

I've also not iced that when you push filament through the Bowden tube and into the head, when it reaches the Teflon part there is a little more resistance to pushing the filament, not great but definitely noticeable. Is this normal compression on the Bowden tube from the Teflon part?

[joergen 2]

So I've installed the V3 hotend?

Are you talking about the official UM V2 hot end, or some other V3 upgrade?

[alaris2 1]

he's talking about the UM v2 hotend,

as opposed to my unofficial v3 metal hotend which prints NYLON in the 'mods' section.

[fluxline 0]

That's two posts I borked yesterday, too tired I guess. alaris is correct, I'm talking about the official UM v2 hotend. On my parts the thickness of the widest part, the retainer, is thicker than the indentation at the top of the peek. So the only contact for the whole hot portion (brass/alu/peek) to keep it from rotating is the Teflon part. I don't think the nozzle hole is in exact alignment with the axis of the hotend due to the gap between the alum block and wood on the front right corner and the other 3 corners making contact.

Yesterday I wrote that I had not seen a problem during printing, but now I have. It can rotate a bit when printing, moving it by hand is easy. I've had a few places where, I think due to changing filament diameter, there is over extrusion and the tip hit when going over the section again, rotating the hotend just a bit. This is just my theory at the moment for what I'm seeing from either it wrongly installed or a part that is not tolerant.

[fluxline 0]

So while rebuilding the head I clearly saw that the bowden tube extended too far down. I think in the instructions online ( http://wiki.ultimaker.com/Hot_end_v2 ) on step 30, while pulling down the teflon insert the bowden must have slipped down. The force exerted by the bowden was enough to keep the hotend not fixed against the housing and keep it from rotating. Still not sure why that step is important, don't even see the need.

I received a new bowden tube with the new hotend and unfortunately, when I first assembled the whole thing I just went ahead and started calibrating, including steps/e. Ran the filament up to the end of the quick release and then used cura to calibrate. After calibrating steps/e I always use printrun to advance the filament to the hotend so it all has the same compression from the feeder mechanism. I did not notice that the bowden is too narrow, very difficult to move filament through by hand. Tested the same filament with the old bowden and it slides through, even when bent. The combination of the two problems has given me three days of non-stop chewed filament.