Just Another Bowden Hotend Design

Hi,

currently I am building a new hotend for my Huxley.

The basic idea was taken from the ReprapPro hotend, but with 3 differences:

1.) I use an airbrush nozzle.
2.) The barrel runs right through the heatsink.
3.) The bowden cable runs straight to the hot end of the barrel.





The barrel is an M6 threaded rod bored 4mm.

The coupling consists of an M6 nut and an M4 nut glued together. The M4 nut cuts a thread into the PTFE bowden cable - very much like the captive nut technique.

The heating block is made of copper.

Detlef

Hey there,
This is a cool design! What temperature does ptfe get soft at? I see it melts at 327 C but if it gets softer earlier you might be in trouble right? Have you considered a water cooled setup that appeared on the reprap blog post recently? Maybe that could alleviate issues and you'd still have a minimalist design. What will keep your airbrush nozzle in place? I know it was considered early on in the rep rap design but I am not sure why it was scrapped.

What kind of connection would secure the ptfe tubing to the hot end? I deal a lot with swagelok for cooling water lines on vacuum equipment and a lot of time you use concentric tubes, I wonder if that would help here. You could just have a hollow barrel where the inlet was on the lower side and the outlet was at the top. You could avoid having a cooling block completely that way but it might just complicate things too much.

Good luck and let us know how it turns out!