I have this clogging problem on my 3D printer that I am having a really hard time to solve. I am a hobbiest so in no way am I a professional with regards to 3D printers. I also know that this is a popular issue and I have tried a lot of the proposed solutions (going through a lot of PLA filament and failed prints) to no avail. I will try to describe the problem and what I have tried to solve it.

First the issue:Removed hortend to show the clog

This shows how the filament clogs. The next image shows the assembled printer head for reference.: Assembled printer head

This is how the print looks when it fails:Failed print

I have tried the following: - Adjusting the temperate between 190 up to 220 for the PLA filament. Everything trying a print with it. - Doing a thorough cleaning of the nozzle (Acetone soak, wire brush, guitar string etc.) - Checking the Teflon pipe inside the tube if it is clear and ensuring that the edges allow the filament to pass through. - Check if the cooling fans work well to ensure cooling of the whole assembly (they work, they aren't jammed etc.) - Dissambling the printer head and putting it back together.

I have printed with the printer before without a problem. I printed PETG a few times to get that working and the results were decent. When I returned to PLA this issue started and no matter what I change on the profile it won't work. I have tried adjusting feedrate, flow rate, retraction amount and speed, temperature, fan speeds to name but a few things.

I have a Cura profile I can upload if that will help. Any advise would be much appreciated. I have been struggling with this for a while now and really need some options.

  • 1
    $\begingroup$ It looks at though your PTFE tube has deformed as a result of over-temperature/heat creep. How is that part cooled/is the cooling working? $\endgroup$
    – 0scar
    Mar 28 '18 at 7:27
  • $\begingroup$ Heat creep was the most obvious answer I could find on the internet but it has not been a problem previously. I did check the PTFE tube and the filament can pass through it comfortably. I also ensured that the edges of the tube is position correctly in the nozzle (correct length, etc). How would I know if the tube is deformed? $\endgroup$
    – koosbeer
    Mar 28 '18 at 9:08
  • 1
    $\begingroup$ It's probably worth keeping some spares and changing the liner tube any time you take the extruder apart -- they are quite cheap and surprisingly easy to damage. $\endgroup$ Mar 28 '18 at 10:12

Sometimes the filament quality itself could be the culprit. Have you tried printing with a different spool of PLA?

  • $\begingroup$ Hi have not tried with a different spool. I will take a stab at that and let you know. Any idea on what else I can try as well? Can it be a setting that is just completely wrong? $\endgroup$
    – koosbeer
    Mar 28 '18 at 7:14
  • $\begingroup$ I printed the same model with the same settings with some of my old, cheaper filament and the print actually finished. So it is the filament. What makes wonder then, what is it about the new, better quality filament that stops it from working well in my printer? Is it the diameter of the filament? The temperature your print at? How can I get my printer to print with this new filament? $\endgroup$
    – koosbeer
    Mar 28 '18 at 9:29
  • $\begingroup$ Sometimes other additives/color in PLA can cause strange jams and print quality issues. When does your filament clog like you showed in the picture? Is it after a retraction move? $\endgroup$
    – PR90
    Mar 29 '18 at 0:06
  • $\begingroup$ Yes I think so. Im changing up the filament to test what has what effect. $\endgroup$
    – koosbeer
    Mar 29 '18 at 6:24

that looks like heat creep.
heat creep is the result of in too much heat in the hot end creeping its way into the cold end. and results in a gradual clogs mid print.

to combat heat creep you need to sink that heat elsewhere and dissipate it.
this is where a heatsink and fan come into play.
the heatsink should be in direct contact with the throat mount/clamp, giving the heat more space to dissipate, and that dissipation is aided by the fan.


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