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massive underextrusion all of a sudden


yesterday after a very good print I started the next on and encountered massive underextrusion from the first layer on. The prinlines are so thin they are barely visible. I tried a lot of diferent settings since, but both extruders underextrude with different filaments at different temps and speeds.

Did anyone encounter a similar problem?

I use a original Creatr (later version) dual extruder for about 2 years now. It is modified with spring loaded extruders, custom nozzle fans, and some other little changes here and there.

- the nozzles are unclogged. Even extruding without the nozzles is incredibly slow

- filament path is not blocked. I get the same results when feeding filament directly.

- extruder pulley is not loose. I double checke dthe grip on the axis.

- temp is stable. At least repetier says so. 

- xyz axis move fine.

- both extruders show the same problem.

- tried different softwares (repetier / octoprint on raspberry), and slicers (slic3r / cura)

- tried original preset settings

Any idea is appreciated.

Cheers, 3dlyx

I've had that problem (same printer and spring loaded also).
The hot ends seem to get plugged after a while. I'm not sure with what or how. I'm guessing cooked plastic sludge :-) Of else the little Teflon bushing inside gets worn.
The first time it happened I replace the hot end. That worked but of course can be expensive.
Now I usually remove the nozzle, heat the extruder and push a small rod through the top (happen to have a long 2mm hex key that works). OR
I have also disassembled the hot end tube and cleaned it up (trimmed a little off the end of the Teflon bushing). In fact I might have removed the bushing on the hot end I'm using mostly now, can't remember.

Anyway, if things are open you should be able to manually push the filament through the hot end quite easily (heated and with the nozzle removed, and the hob gear pulled aside).


 Hi Robert, thanks for your info. I did try to clean the hotends already before, with a 1.5mm dremel drill and a kitchen torch, but with very little success. I guess my hotends are pretty spoiled by two years of nearly continous printing so some new parts here and the wont hurt much.

I ordered two new hotends and a new fan, (as I broke one while disassembling the extruder). As soon as I get them and have them built in the printer, I'll give Info of how it worked out.



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