For months, I have had a piece of Vespel Polyimide sitting on a shelf. Last week, a customer asked if I had anything that would print at a higher temperature than the standard J-Head. After I mentioned that Vespel Polyimide is rated for 288 degrees he expressed interest in testing it. This weekend, I finished machining it and it is shipping out today.
As PTFE is only rated for 260 degrees, a Rulon liner had to be used as Rulon is rated for 288 degrees. Since this hot-end is quite special, I decided to assemble it with a 2024 aluminum nozzle. Set screws have also been added to retain the heater cartridge.