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CellarDoor
(@cellardoor)
Eminent Member
Extruision Problems

I am printing since september and for most of the time (after a few starting problems) everything worked fine, but before christmas the extrusion often stopped during print.
Today I got the time to look at the extrusion, estepcially at the stepper. I noticed the following problem that I can't solve (even after two hours fidelling with the tension).

Not the tension screws are at exactely 13.5mm, and the filament nicely moves into the hot end when doing the first part manually (not using loading filament to see what goes wrong).

At first the filament moves at constant speed and nicely, but after 36mm
the stepper starts to skip movement leaving marks on the filament, there is no filament coming out at the bottom after a first few milimeters.

I don't really know what to do now. Any ideas?
I printed about a kilometer of filament before that without problems.

Posted : 29/12/2017 9:59 am
CellarDoor
(@cellardoor)
Eminent Member
Topic starter answered:
Re: Extruision Problems

So I worked for two days straight on the problem and i can't get it running 🙁

I put the extruder into acetone and waited for a night - but nothing new, the extrusion does not work.
I can't get the nozzle off (preheated, opened front like described in the manual) but I can't screw the nozzle... any ideas?

Posted : 31/12/2017 7:27 am
David
(@david-37)
Eminent Member
Re: Extruision Problems

We are in the same boat. The filament won't budge.

Posted : 01/01/2018 10:41 pm
CellarDoor
(@cellardoor)
Eminent Member
Topic starter answered:
Re: Extruision Problems

Oh I didn't try to use the hotend without nozzle (that's what yours looks like), I put both the nozzle and the upper part (you can unscrew from the actively heated part of the hotend) into acetone for two days, I am not yet sure, whether that'll do the job.

The nozzleis nice and clean, the upper part is still not completely free, but before testing, I am still struggling with getting the nozzle back on (partly because the temp sensor got loose and sometimes when I try to screw the nozzle, I am just ending up hearing a loud beep due to max temp (shortage in the temp sensor cable).

Posted : 02/01/2018 6:53 am
CellarDoor
(@cellardoor)
Eminent Member
Topic starter answered:
Re: Extruision Problems

Here's a quick shot of what I end up having trouble with (despite not knowing whether the upper part of the hot end already works, but that might be fixed by longer acetone baths):

My temp sensor came loose and now its more like gambling whether I get a max_temp_error (which always occurs with a loud beeping noise, which is ok I think but still if you get that every 5 minutes it's a little annoying and more like playing hot wire).

Posted : 02/01/2018 8:10 am
Frank
(@frank-14)
Eminent Member
Re: Extruision Problems

If you were printing PLA, acetone wont help, only works for ABS.
Theoretically Chloroform would help, but please dont try. Just too dangerous.
Otherwise, if it is a full metal hot-end, disassemble and see what you can see. Most probably there was/is a slight gap between the nozzle and the heatbreak. That little space can fill up with filament and cause blockage after it cools
Burning it out is one method that seems to work, but please keep it safe.

Posted : 02/01/2018 9:13 pm
Frank
(@frank-14)
Eminent Member
Re: Extruision Problems

As for the last picture, I dont like that one. Very high chance of a short circuit on the thermistor. Maybe time to replace the hot end ? Or at least the heatblock/heatbreak/nozzle combo. When based in Europe, E3D delivers really high quality hot ends, Or ask Prusa. If adventurous, buy a clone off Aliexpress. Dirt cheap and in a pinch they do the job at least for a little while

Posted : 02/01/2018 9:17 pm
CellarDoor
(@cellardoor)
Eminent Member
Topic starter answered:
Re: Extruision Problems

Yes, I feared that, though the hotend is only a few moths in use, that one just fell off when I was taking it apart to clean the hotend. I am in contact with Prusa already (and already feared that that might not be fixable). Yes I am based in Europe.

Posted : 02/01/2018 9:59 pm
CellarDoor
(@cellardoor)
Eminent Member
Topic starter answered:
Re: Extruision Problems

So I ordered a new hotend and it arrived last week. Until then, 3-4 days of acetone and continuously poking into the old hotend released all old abs, so I have them still working (i think).
The hotend even came with a new nozzle, took some time to do the wiring into the Rambo board (haven't done that before). But the first running test print now seems to work 🙂
So the lesson learned is: don't loose your temperature sensor at the hotend.

Posted : 21/01/2018 2:37 pm
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