Kywoo Tycoon 3D - Impossible to print after using PETG

[Bikeracer2020]

Does the extruder have a teflon tube between the exruder and the nozzle?

If it does is there any sign of degradation? Also check that the end is cut square and fits snugly up to the nozzle.

[mosdev38]

In fact, there was a Teflon hut in the hotend. It shrunk quite a bit at the end, about 0.3 mm to be exact. If you run your fingers along it, you can feel how it tapers off considerably. The sleeve is also totally clogged. Can I shorten the shrunken end and put it back into the hotend or does the sleeve have to be as long as the hotend? Can I purchase these sleeves separately or buy the component directly?How can this actually happen, I mean I have printed within the given framework conditions released by the manufacturer.Many thanks for your help!

[Bikeracer2020]

You can cut a piece of new teflon tube, make sure the cut is at 90 degrees at the end and a snug fit against the nozzle.

Ideally you need to convert to a bi-metal hotend with a heat break above the nozzle.in it .

I had the same problem with my Qidi standard hot end, the manufacturers state the hot end is capable of the temp you want, but on enquiring it is not suitable for prolonged use at the higher temp specfied.
I converted mine to an all metal hot end and have had no more problems with the hot end at 250/260 degrees.

There are loads of different bi-metal replacement parts on Amazon, you need to search for one that fits, some screw in with usually a 6mm or 7mm thread or are held in place with a grub screw.

[mosdev38]

I was lucky and the original upgrade kit for my printer was on offer.It's a complete hotend with bimetal and hardened nozzle. The kit allows printing up to 300 degrees.When it arrives, I will report whether everything is working as it should. Many thanks for your help, I would never have thought that the Teflon tube was the problem.

[Bikeracer2020]

Just be aware that a hardened steel nozzle might cause problems for normal plastic filament, if it does, just fit a normal brass nozzle.
I believe it's to do with the friction of the hardened steel, anyway just try it first.

Also if you change a nozzle, heat the heater block up by 10-20 degrees above your normal print temps and then tighten the nozzle home, same when removing a nozzle. This is to prevent leaking filament.