3D printer stops extruding

[gte718p]

Any 3D printer gurus here?

I have a cheap monoprice III3 printer. On small things it seems to do great. On longer print jobs it stops extruding somewhere into the print job. It is not consistent when.

It looks like I'm having heat soak issues, but I put a giant fan on it and it had no impact. I have attached a picture of the ends I extract. It has a big blob that is jamming in the print head and then a thin section, before returning to normal.

I'm printing pls plus at 55mm/m and 205 deg.

 

[Meleon]

is there a heatsink after the heater block? it look like heat soak to me also. looks like the filament is stretching when its being retracted and binds when it tries to extrude again.
there should be a way to create a thermal break between the hot end and the upper part of the extruder where your fan should be blowing. I don't know what kind of extruder that machine runs though so I'm not much help. check out http://forums.reprap.org/

 

[gte718p]

Thanks,

The hot end is attached to the heat sink. There is a small fan on the head sink. There is also a nylon sleeve that I believe is supposed to be a heat break between the hot end and the feeder.

That kind of aligns with what I thought was happening so I turned retraction off for my last print. Didn't help.

I have been playing with temps and speed with no luck. Unfortunately I have not clogged the nozzle. I need to buy a new one or buy a .4 mm drill. I'm leaning towards the nozzles being disposable. I imagine it is super easy to break a .4 mm drill bit.

 

[Meleon]

i can't remember completely but I've had the same problem a couple of years ago. I found some hot end assembly videos on youtube. there is a certain way heated block has to attach to the heatsink to create the thermal block. I know it solved my problem.
you might be able to heat the nozzle up with a torch to clear the clog.