Jump to content
Ultimaker Community of 3D Printing Experts

Massive jam of PLA between nozzle and print core - suggestions?

Recommended Posts

It appears the print core has a jammed full of the extruded filament and it has continued to extrude filament for the entire print causing a mass of PLA plastic to form between the print core and the nozzle. 
I've found similar such errors on Ultimaker forums here and have contacted them for advise and approach to repair whilst in warranty.
Has anyone been able to get this covered by warranty? 
What is the suggested approach, heat the PLA with an airgun and remove?
The explanation on the forums is that the part failed to stick to the bed despite using the recommended settings. The part was dragged around on the bed and the nozzle kept extruding on the same large mass of plastic.  

Image from iOS (2).jpg

Share this post

Link to post
Share on other sites

I've just had the same problem. It was an overnight print. Something slipped on the plate,with the result that I have this badly bunged up print core. I had this happen once before, some six months back, and that involved nylon so all I could do was get it repaired by Ultimaker/3DGBIRE. This time around, the blockage is PLA. I did a bit of work with a heat gun, and started to be able to strip away bits on the congealed mess. Clearly, it will take hours to clear the major blob, but is it worth it because, the closer I get to the actual print core, surely my heat gun will be damaging the electronics and producing subtle distortions. Has anyone successfully cleaned up one of these messes? If so, how did you do it?



Share this post

Link to post
Share on other sites

I've had this advice from 3DGBIRE


Heating the nozzles up to 260 and leaving for around 5-10 minutes should soften the material around the nozzles allowing for easy removal. Once removed the initial blob, using a brass wire brush on the printcores can help clean these up and allow removal from the printhead for further cleaning using the wire brush. Using a soldering iron on low heat can also assist with this if the material is around the wires on the printcores. Avoid using the heat gun as this will put heat on components that are sensitive to heat

Share this post

Link to post
Share on other sites

I've had the same with PLA.


I couldn't even heat up the nozzles anymore because the material pulled out a cable on one of the printcores, which caused the UM to fail out immedeately after starting up. 

As I feared to damage anything with the heat gun, I decided to use a soldering iron to cut out the material piece for piece. I used a temperature regulated one to keep it hot enough to melt the PLA kind of fast but not so hot that it melts the other plastic parts of the print head when I accidently touched them.


So it was many hours of work and as soon as I could recover one part of the print head, I disassembled that one to get better reachability of the remaining PLA. 

Unfortunately I could only get one printcore out in the end by destroying it completely. But still better than having to buy a whole new print head assembly.

Share this post

Link to post
Share on other sites

A regulated heat gun can also help if you don't have a regulated soldering iron. If you can go to 80° with the heat gun, you should be able to soften the material enough without destroying something else. But in any case, it is a work of several hours. 


Check Youmagine; there are some brackets to print, to secure the print head fan door that it cannot open by an accident.

Share this post

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Our picks

    • Ultimaker Cura | a new interface
      We're not only trying to always make Ultimaker Cura better with the usual new features and improvements we build, but we're also trying to make it more pleasant to operate. The interface was the focus for the upcoming release, from which we would already like to present you the first glance. 
        • Like
      • 117 replies
    • "Back To The Future" using Generative Design & Investment Casting
      Designing for light-weight parts is becoming more important, and I’m a firm believer in the need to produce lighter weight, less over-engineered parts for the future. This is for sustainability reasons because we need to be using less raw materials and, in things like transportation, it impacts the energy usage of the product during it’s service life.
        • Like
      • 12 replies

Important Information

Welcome to the Ultimaker Community of 3D printing experts. Visit the following links to read more about our Terms of Use or our Privacy Policy. Thank you!