Extrusion stops after few minutes

[Rabin_Dhamala 0]

I have been using ultimaker 2+ for around 1 and half year and recently I faced this problem of stopping of extrusion and the printer printing in air without extruding the filament completely after few minutes of printing. All the three fans are working properly too. When this happens and I try to revert the filament the filament doesn't revert and I need to pull out the bowden tube and pull out the filament forcibly and then carry out the atomic method to clear out the remaining parts of the filament from the hot end. Again if I start the printing process, the same problem occurs again and again. I have only used PLA filament with it. What might be the issue that's causing this problem ??Please help me out to solve this

[gr5 1,998]

Have you changed the PTFE/teflon part?  That's the most likely problem.  If that doesn't fix your issue I have a list of other things you can check but most likely it's the teflon part.  They are considered an expendable.  You should be changing it every 200-500 hours roughly.  You can check how many hours you've printed so far in the menu system.

 

You can get a few extra hours while waiting for the replacement part by drilling it out with a drill bit of size 3mm to 3.25mm.  Without taking anything apart (just remove the nozzle and drill upwards carefully).  You can also remove the nozzle and insert filament from below to feel the friction in that part.

 

Also if you have never done a cold pull on a UM2 then read about how to do this properly or watch some videos of people explaining it.

[Rabin_Dhamala 0]

Thank you so much for your quick reply. As you said I opened up the hot end and checked out the TFM coupler but could not change it because of not having a spare one but I have attached the image of it here which something looks like this from the top view.

I also cleaned up the feeder and the bowden tube and after reassembling the hot end I carried out the atomic method to clean the nozzle and the image of the PLA filament used during the atomic method looks like this.

Before all of this when I physically pulled out the filament from the nozzle because of not inverting of the material as I mentioned you before I got this.

Do I still need to wait for the TFM coupler before starting the print or the problem is something else? 

[gr5 1,998]

The problem with the TFM is that it get soft after weeks at temperatures above 200C.  So it looks fine now but if you compress it then it will squeeze the filament.

 

That is why I suggested you drill it out *while it was still inside your printer*.  

 

The best way to test the TFM is to install it but remove the nozzle and slide filament through the TFM from below (while block is cold - <50C).  There should be no friction from the TFM.  The feeder can push with about 3-5kg of force - that's your budget.  5kg.  If the tfn is using up 0.1kg then that's fine.  But if the TFM is using up 1/2kg of your budget then that's a lot and will cause some underextrusion.

[Rabin_Dhamala 0]

I removed the nozzle and inserted the filament from below as you said but the filament is totally obstructed to move any further right from the beginning of the TFM coupler from below. So your suggestion of drilling it out must be perfect in this case. But I am not confident enough to drill it directly through the hot end without screwing things up.

??

So is it okay if I drill it by taking the coupler out from the hot end or should I do it through the hot end itself??

[geert_2 556]

Whatever way you drill (I don't know what is optimal so I leave that to gr5 to answer), I would recommend using a *hand drill*, not an electrical drill. This gives you a much better feeling and control. I bought a separate drill chuck for this. It gives a good grip and allows to apply enough force, but you can still drill very gentle manually. It is also usefull for drilling out holes in 3D-printed models: when using an electrical drill in PLA models, they will melt immediately; but not with this manual drill.

 

 

For cleaning ashes and debris out of a teflon coupler or nozzle (on my UM2 non-plus printers), and for removing minor deformations, I often use a long brass M3 thread rod with rounded edge. By moving up and down and scratch the walls of the nozzle, this works as a very gentle file. A brass thread is far less agressive than real files, or than steel M3 threads, so it is less likely to do any damage. If the gentle approach does not work well enough, you can still go to more agressive methods.