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amanda.r
(@amanda-r)
Active Member
Nozzle clog issue

Hi guys,
I'm at my wits end. I have a Prusa i3 1.75mm printer that I just finished building this week. Yesterday was print day and I was able to print out the PRUSA logo and the JP whistle, no problem. This morning, I go for something slightly more challenging from Thingiverse. Here's what happened.
1. I loaded up the gcode and it started to print the bottom layer but I realized I'd made the print too large (some filament went off the side).
2. No problem, I stopped the print, cleaned up the bed, and added some more ABS juice.
3. I tried again with new code, but now the filament wouldn't come out.
4. I took off the nozzle to try to clean out any filament. I did this by soaking the nozzle in acetone for a while.
5. I tried my friend's nozzle on the extruder to see if anything would print out of that. No dice.
6. I unloaded the filament checked the golden pulley at the top of the extruder and discovered it was loose, so I tightened that.
7. I there were several tick marks on the side of the filament I unloaded as if the pulley had been grinding against it.
8. I put my nozzle back on the extruder and let it heat up so I could stick a 0.35mm pin through the nozzle. However, I could not get the nozzle flush with the hot end like it is in the pictures in the manual, it's about 1mm off.
9. I reloaded the filament and it went in pretty far, but seemed to get stuck near the bottom because the pulley started to tick against it. With the nozzle clear and heated and the filament loaded, I tried to print the logo again and that failed with no filament coming out of the nozzle.
10. When I unloaded the filament it was about 70cm long and covered in tick marks and the bottom was discolored to brown a little bit. Why didn't it melt?

So now what? Tomorrow I'm going to take the nozzle off and just see if it's clogged in the extruder itself (by using the manual extruder function). If so, what can I do? I am afraid to take this stuff apart after getting it together since I don't have extra printed parts and I'm sure I will break them if I have to take out the heating element. Help!

Posted : 19/11/2015 11:31 pm
philippe.c2
(@philippe-c2)
Active Member
Re: Nozzle clog issue

Hello,
I have the same issue (see two post below) ..
Nozzle is clogged .. just happen in the middle of a print with Prusas3d ABS ...
I tried to heat, load, unload clean with acetone, putting a small wire inside .. no way ?!?

Posted : 20/11/2015 10:42 am
PJR
 PJR
(@pjr)
Antient Member Moderator
Re: Nozzle clog issue

Amanda

Unfortunately, with 3D printers, you are going to have to get used to carrying out regular maintenance, including dismantling and cleaning the nozzle and barrel.

You will also need to have a supply of spare parts close to hand.

The good news is that as you become more experienced with the printers, your maintenance down time will be significantly reduced. You will quickly find out the best temperatures for your printer and the different filaments, which will reduce blockages such as this.

I think in this instance, you will have to remove and manually clean out the barrel and clean/replace the nozzle.

Peter

Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…

Posted : 20/11/2015 12:00 pm
amanda.r
(@amanda-r)
Active Member
Topic starter answered:
Re: Nozzle clog issue

Hi all,
I just wanted to post an update. I took the extruder apart and discovered that the white plastic tube in the barrel had migrated down to the hot end and deformed. This was causing the clog. I snipped off the deformed end and put everything back but now I'm concerned as there seems to be no way to keep the tube from moving down into the hot end. Can I get a replacement for this piece if it happens again? Can I get rid of this piece all together or is it integral? I'm printing now but feel pretty insecure about future prints.

Posted : 29/11/2015 8:19 pm
PJR
 PJR
(@pjr)
Antient Member Moderator
Re: Nozzle clog issue

Hi Amanda

Great to hear you are up and running again. PTFE tubing is available here: http://e3d-online.com/Mechanical/Bowden/Bowden-Tubing-1.75mm

Or you can get it on eBay (which may be quicker for you): PTFE tube, 4mm external diameter, 2mm internal diameter.

Just ensure that the ends are cut as square as possible.

Peter

EDIT: when printing, ensure that you don't exceed the manufacturer's maximum temperature of 245 degrees C. PTFE starts to soften just above this and car start to deform.

Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…

Posted : 30/11/2015 1:12 pm
amanda.r
(@amanda-r)
Active Member
Topic starter answered:
Re: Nozzle clog issue

Will do, thank you for the link. As a note, the ABS preheat in the display software has the nozzle default set to 255C. I will adjust for future use.

Posted : 30/11/2015 6:08 pm
PJR
 PJR
(@pjr)
Antient Member Moderator
Re: Nozzle clog issue

Amanda

Yes, the 255 degrees is a correct figure, although ABS will extrude at lower temperatures. At 255 degrees, I personally think that it's pushing a little too high, but Josef has already confirmed that this temperature should be fine.

It's up to you; personally, I was taught to be cautious and so would go with the lower figure.

Peter

Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…

Posted : 30/11/2015 6:33 pm
philippe.c2
(@philippe-c2)
Active Member
Re: Nozzle clog issue

Hello,

Just a small feedback ..I managed to unclog it with one small iron wire (one of an iron brush)

Now it is ok but I noticed that the extruder springs were too tight .. and that was spoiling the filament I untight them and no problem since then

Philippe

Posted : 07/12/2015 10:36 am
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