Ultimaker 2+ stops extruding about 20 minutes into a print and filament is then stuck

[burrowsa 0]

Hi

After many happy months printing on my UM2+ I recently hit a problem that means I can no longer print. Early on in the print the fillament stops extruding and when I go to investigate I find that the end of the fillament is stuck in the bowden tube. I can reproduce this problem with models that I've printed several times in the past without any problems. I've inspected the inside of the feeder and all looks OK, I've tried more or less feeder tension and it makes no difference, I have tried a new nozzle and a new bowden tube but nothing so far has helped. The problem occurs for all models that I try and print. As far as I can work out the problem is that the end of the fillament is going a bit weird, below are some photos - has anyone seen this before? What could be causing it?

Cheers

Andy

[neotko 1,417]

First ideas to check

a) Small fan behind the hotend. Is it spinning when the hotend reach 40-50C ?

b) Are you 100% sure the bowden is all the way in, inside the TFM coupler? Is very easy to fell that is while isn't. Wiggle it a bit until it really goes in. To double check compare the distance of bowden that goes in with the distance outside.

c) Is the filament 2.85mm? Anything bigger than 3.00 mm can cause troubles.

[gr5 2,210]

It's most likely #A above. But there are other possibilities. Such as #B above.

[burrowsa 0]

Thanks for the replies. I checked the little fan around the back and it was not comming on when the hotend got hot. I ordered a new one but then tried wiggling the wires on the original and now it is working again. I've done a couple of prints since and all is working fine again. I'll almost certainly fit the new fan when it arrives just in case.

Thanks for the replies they were really helpful.

Cheers

Andy

[gr5 2,210]

I strongly recommend you don't change fans as the problem is with the wiring and not the fan. You could just break more wires in there.

[DidierKlein 729]

Did you check the connection of that fan?