What is the best way to clean off extra TPU Filament from an Ultimaker s5 nozzle? Also is there a typical reason why so much TPU is sticking to the nozzle?

[andrewtg161 0]

I am trying to clean extra TPU off of an Ultimaker s5 nozzle, and I want to know what the best way to remove the TPU is? Should I just heat the nozzle and wipe it off? Clean it with a sonic cleaner etc. Which is the best way without damaging the nozzle. Also what would cause so much of the TPU to stick to the nozzle? I have attached a couple of photos to show what it looks like. Could this be a calibration problem with the nozzle? Or possible a temperature problem with the special type of TPU I am using? 

[geert_2 557]

Some materials are very sticky like hotglue. The PET that I have also has this tendency. Hot PLA is more like yoghurt and doesn't accumulate so much. No experience with TPU though.

 

Immediately after a print completes, I wipe off the nozzle with a strong thick paper tissue, while it is still hot and the goo still soft. Use thick or folded paper tissue, to not burn your fingers.

 

If the goo is too much burnt-in, I remove it with a long brass M3 bolt or threaded rod. This works as a gentle file. Of course, never use steel or sandpaper or so, as that would destroy the nozzle. Use brass that is softer than the nozzle but harder than the plastic debris.

 

What also seemed to help me, was adding a droplet of silicone or PTFE oil to a tissue, and then wiping the nozzle with that, prior to starting a print. Seems to have some effect, but not totally prevent it.

 

All this is for my UM2 printers, and it obviously falls into the category of non-official personal methods. I don't know if they are usable for other models, so all is at your own risk...