Clogged extruder ?

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Hugues
Posts: 270
Joined: Thu Apr 04, 2013 5:36 pm

Clogged extruder ?

Post by Hugues »

Definitely not a good week-end for me, after 2-3 weeks of trouble free printing.

AFter a sagging print assembly, then a blown thermistor, my extruder is now clogged. :evil:

It extrudes a very small filament and it curls right away under the hot tip. I tried pushing the filament manually but i cannot make it extrude normally. I'm using ABS at 240c. I tried the technique described on this forum, i un-screwed the extruder bolt and pulled back quickly the filament to try to remove any material from the hot end, i did this several times, nothing special came out. It looks like something is blocking the final tip of the extruder.

I have a thought as i'm writing these lines: I just changed my thermistor. Maybe it's just a coincidence that my extruder jams for the first time, but maybe not. What if my thermistor does not read the correct temperature and my hot end is not really at 240 C ? How about if it is in reality much lower ? Does a too low extruding temp behaves like i describe above ? I don't have another way of reading my temp so....or maybe if i swap the thermistor readings in the electronic box i might see if they are reading the same.....i bought a 100kohm thermistor here:
http://www.fabberworld.com/Electronics/ ... m::46.html

If my hypothesis is correct: is there a variable i need to set somewhere to tell the system which thermistor i'm using ?
Hugues
Regards from Switzerland

Hugues
Posts: 270
Joined: Thu Apr 04, 2013 5:36 pm

Post by Hugues »

edit

i swapped the thermistor wires and it makes no difference.

i increased the hot end temperature to 270, no difference, the extrusion is barely coming out and it's curling up, even if i push it myself manually.

Looks like there is something partially blocking the tip of the extruder. How to fix this ? I'm not too keen to stick anything in a 0.35 mm hole made out of aluminum....
Hugues
Regards from Switzerland

satoer
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Joined: Mon Oct 01, 2012 8:00 pm
Location: Netherlands

Post by satoer »

Use a piece of guitar string to floss youre extruder.
My Felix 1.5 printed designs on Thingiverse
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Hugues
Posts: 270
Joined: Thu Apr 04, 2013 5:36 pm

Post by Hugues »

well, i finally decided to give it a go, i found a tiny electrical copper wire with a diameter of 0.29mm, so i inserted it slowly into the tip. AT first i could not insert it, like i could not find the opening, or something was blocking it. Then I managed to insert it about a cm or so, then i tried to extract again and it worked.

So, i hope i did not damage the tip doing so...
Hugues
Regards from Switzerland

angryangel
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Post by angryangel »

of you print abs you als can clean the hotend with aceton because aceton dessolves ABS perhaps this is a saver way to clean it without demage the nozzel

Hugues
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Joined: Thu Apr 04, 2013 5:36 pm

Post by Hugues »

angryangel wrote:of you print abs you als can clean the hotend with aceton because aceton dessolves ABS perhaps this is a saver way to clean it without demage the nozzel
I was thinking of pouring acetone in a small cup and bringing it under the tip, then I realized the tip is at 240c and that might not be so cool in a cup of acetone , he he .

So I'll clean it up later with acetone when it has cooled down to room temperature, safer .
Hugues
Regards from Switzerland

dognotdog
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Joined: Tue Sep 04, 2012 9:22 pm

Post by dognotdog »

From my experience, if the tip is even moderately hot, the acetone will evaporate before getting to the insides, so it's not really useful.

satoer
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Post by satoer »

don't know if you've done this already: Feed the fillament through a piece of sponge to clean the fillament just before it goes into the extruder.
My Felix 1.5 printed designs on Thingiverse
E3D V6 Hot end upgrade for your Felix
Tweezer bracket for your Felix
Led bar upgrade for your Felix

angryangel
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Post by angryangel »

i never thougt to cleane the tip with aceton when its hot

i thought to clean it with aceton when its cold, aceton disolves ABS also when it is cold

Lioric
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Joined: Wed Aug 15, 2012 1:13 am

Post by Lioric »

But what clogs the tip is not the ABS, or it would be melted at working temps. What clogs the tip usually is some particles of dust or something contained in the filament, but not plastic. So acetone is not going to work with that.

If you insert anything to clean the tip, expect to replace your extruder soon (decreased quality might result). The material in the tip area is really soft.

The is why I proposed to move to the e3d extruder with easily replaceable tips

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