<p>I found the issue. The fan, blowing on the heat sink is busy packing up. It must have stopped during a print (or not start at all). I now check that it is turning when the print starts (and check on it from time to time). I'll have to wait for stock to come in before I can replace it.</p>

CC BY-SA 4.0
2022-09-01T10:56:08.287Z
If not enough cooling on the cold end, the issue called "heat creep" kicks in. This is an excellent example of heat creep, thanks for answering your own question. Sorry to have missed your question, you would have gotten an answer sooner! :-) All-metal heat breaks are notorious for causing this issue.
0scar
CC BY-SA 4.0
2022-09-01T13:51:16.043Z
Yes your description is related to heat creep (https://3dprinting.stackexchange.com/questions/15629/what-are-ways-to-avoid-heat-creep).  Looking at your question, I was going to suggest increasing the cooling of the heat sink to give a higher temperature gradient.  Your solution is consistent with that.
Perry Webb
CC BY-SA 4.0
2022-09-01T10:01:31.467Z
2022-09-01T10:01:31.467Z
TungstenX
<p>The filament &quot;swells&quot; up to the inner diameter of the feeding pipe, from the nozzle to about the end of the heat-sink. This happens after a few hours of printing. It happened using a new nozzle (0.2 mm) and a new tube - the same clog is the reason why I changed both.  When this happens, the filament can't be pulled from the tube - I had to cut it open on the end to remove the filament, thus shortening the tube with each clog. The nozzle had no filament in it when I removed it and isn't clogged up.</p>
<p>When installing the nozzle and tube, I first screw in the nozzle, heat it up and torque it a bit, then I slide the tube in all the way.</p>
<p><a href="https://i.sstatic.net/cb8AJ.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/cb8AJ.jpg" alt="Length of thick filament" /></a></p>
<p><a href="https://i.sstatic.net/Aa8CR.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/Aa8CR.jpg" alt="No filament in nozzle" /></a></p>

CC BY-SA 4.0
2022-08-29T08:32:38.983Z
What kind of pipe and filament are you using? I am not sure about the core issue but regarding the tube cutting: caution about a too short tube length after some cutting repetitions. Also something like [this cutting guide](https://www.thingiverse.com/thing:1737224) can help to get a nice orthogonal cut.
Andre S.
<creality-ender-3>
Ender 3 v2 - Filament clog before nozzle
TungstenX
# Ender 3 v2 - Filament clog before nozzle

(Asked by: username_0 on 2022-08-24)

The filament "swells" up to the inner diameter of the feeding pipe, from the nozzle to about the end of the heat-sink. This happens after a few hours of printing. It happened using a new nozzle (0.2 mm) and a new tube - the same clog is the reason why I changed both. When this happens, the filament can't be pulled from the tube - I had to cut it open on the end to remove the filament, thus shortening the tube with each clog. The nozzle had no filament in it when I removed it and isn't clogged up.

When installing the nozzle and tube, I first screw in the nozzle, heat it up and torque it a bit, then I slide the tube in all the way.

[![Length of thick filament](https://i.sstatic.net/cb8AJ.jpg)](https://i.sstatic.net/cb8AJ.jpg)

[![No filament in nozzle](https://i.sstatic.net/Aa8CR.jpg)](https://i.sstatic.net/Aa8CR.jpg)

**Tags:** creality-ender-3
> **Comments:**
> **username_1**: What kind of pipe and filament are you using? I am not sure about the core issue but regarding the tube cutting: caution about a too short tube length after some cutting repetitions. Also something like [this cutting guide](https://www.thingiverse.com/thing:1737224) can help to get a nice orthogonal cut.  

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## 1 answers

### Answer by username_0 on 2022-09-01. Score: 3

I found the issue. The fan, blowing on the heat sink is busy packing up. It must have stopped during a print (or not start at all). I now check that it is turning when the print starts (and check on it from time to time). I'll have to wait for stock to come in before I can replace it.

> **Comments:**
> **username_2**: If not enough cooling on the cold end, the issue called "heat creep" kicks in. This is an excellent example of heat creep, thanks for answering your own question. Sorry to have missed your question, you would have gotten an answer sooner! :-) All-metal heat breaks are notorious for causing this issue.  
> **username_3**: Yes your description is related to heat creep (https://3dprinting.stackexchange.com/questions/15629/what-are-ways-to-avoid-heat-creep).  Looking at your question, I was going to suggest increasing the cooling of the heat sink to give a higher temperature gradient.  Your solution is consistent with that.  

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