This is redesigned version hot end to replace the fault prone UM hot end. It is designed to bolt on to an otherwise standard assembly. A lathe and drill press are necessary to machine the parts. This design offers a single improved connection between the bowden tube and nozzle to eliminate leaks and plugs. The nozzle is designed for quick change-over.
I have been working on a solution to the common hot end problems with the Ultimaker. I have been hesitant to show my work because I wanted to prove its effectiveness. I now have about 30 hours of printing with good success. More testing is in order. Some features to the design:
-M7 thread on the bowden tube
-New peek block with M7 thread through and chamfer on bottom side to effect 'flare' connection with nozzle
-New heater block accepts standard heater and thermistor. Longer body for more thread engagement. Turned down to reduce heated mass.
-New nozzle with male flare compresses end of bowden tube against PEEK.
-As tested has .4mm tip.
-Less connections for possible leaks. The bowden tube has a flare connection directly to the nozzle.
-Quick nozzle change-over
-Insulator is still PEEK
-Mounts in standard wood block (part 10b?) with white/blue clip. I think the clip is now unnecessary though.
-Same stack-up height as original equipment so 'z' switch can stay in same range
-Stable temperture with standard Marlin PID settings
-No PTFE tape
-Nozzle bore has 60 deg included bottom for better flow (hopefully)
-Lathe and Drill press needed to make new parts.
Last 2 pics show nozzle after printing for inspection. Filament pulled back while hot. Dis-assembled while cold. One shot looking up bowden tube for plugs. Last shot of flare side of nozzle. The PLA attached to the nozzle was not a 'plug', but did need to be twisted free of bowden tube.
As most people don't have access to the tools necessary to make this thing, I am considering offering this as a kit if further testing proves reliability and sufficient interest is shown.
Work in progress. Looking for comments and feedback.