Undefined PTFE/Brass Nozzle I’m not going to say all that much about this type of Hot-end apart from being wary about trying to use it. I did not have high hopes because it’s using PTFE for the thermal break and also as mechanical support. The main issue with any nozzle that uses PTFE as a mechanical element is the fact that it changes dimensions as it heats up. This nozzle is 0.2mm so a very accurate distance from the bed is required to get the first layer down well. If that distance changes due to temperature you will have no end of problems trying to calibrate it.
I bought this fully assembled. It has been made very well, but with materials that cause issues for Hot-ends.
The nozzle does come with metal studding, but because the studs are also fitted to a PTFE disc this does not stop the thermal expansion issues causing a variable distance for the nozzle. That alone makes it not worth the effort of trying to use this type of nozzle. What can I say, not recommended for use in a 3D printer...
Future hot-ends and nozzles We are going to see a lot more experimental mixing nozzles, lighter all metal designs and higher temperature materials, driving all sorts of new nozzle designs. And remember you can still make your own, it’s not that hard to do and good results can be achieved with basic tools and a drill press. I would be great to see some standards for 6mm brass nozzles agreed, at the moment we have a lot of ‘compatible’ looking M6 threaded brass nozzles, but they all have different sealing flats or pressure sealing angles and fitting the wrong type or length can cause.
Older style RepRap hot-ends had similar issues with PTFE and PEEK expansion, long melt zones and melting.