<p>This is a typical sign, that your hotend wasn't tightened properly. Carefully heat it up and remove all the plastic you can while removing the heatbreak - that's what you call transition screw.</p>

<p>After cleaning, screw in the heatbreak and the nozzle. The nozzle should butt agains the heatbreak, but have at least 2 threads to the heating block. Reassamble the full hotend now by adding the coolend.</p>

<p>Finally heat the hotend on the full assembly to about 240 °C and tighten the nozzle against the heatbreak again. This is called hot-tightening. You can add the PTFE liner after the hot tightening.</p>

CC BY-SA 4.0
2020-03-01T15:31:34.503Z
2020-03-01T15:31:34.503Z
Trish
<p>My custom printer is affected by a strange problem. After 30/40 min printing without any problem, PLA starts blobbing from the top of the hotend.</p>

<p><a href="https://i.sstatic.net/RvZ3V.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/RvZ3V.jpg" alt="enter image description here"></a></p>

<p>What does it means? Where to start checking?</p>

<p>It is possible that there is a little space between nozzle screw and transition screw inside the hotend?</p>

CC BY-SA 4.0
2020-03-01T21:50:35.587Z
I've had the same problem, and the answer you selected fixed it.
cmm
<hotend>
PLA from the top of the hotend
danyolgiax
# PLA from the top of the hotend

(Asked by: username_0 on 2020-03-01)

My custom printer is affected by a strange problem. After 30/40 min printing without any problem, PLA starts blobbing from the top of the hotend.

[![enter image description here](https://i.sstatic.net/RvZ3V.jpg)](https://i.sstatic.net/RvZ3V.jpg)

What does it means? Where to start checking?

It is possible that there is a little space between nozzle screw and transition screw inside the hotend?

**Tags:** hotend

> **Comments:**
> **username_1**: I've had the same problem, and the answer you selected fixed it.  

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## 1 answers

### Answer by username_2 on 2020-03-01. Score: 4 | Accepted answer

This is a typical sign, that your hotend wasn't tightened properly. Carefully heat it up and remove all the plastic you can while removing the heatbreak - that's what you call transition screw.

After cleaning, screw in the heatbreak and the nozzle. The nozzle should butt agains the heatbreak, but have at least 2 threads to the heating block. Reassamble the full hotend now by adding the coolend.

Finally heat the hotend on the full assembly to about 240 °C and tighten the nozzle against the heatbreak again. This is called hot-tightening. You can add the PTFE liner after the hot tightening.


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