Saturday, August 23, 2008
The holding block has a hole for the catridget heater, and holds the barrel via a clamping arrangement with the bolts at the top.
I wanted to operate at temperatures above what PTFE could handle, so I used a three-part extruder barrel:
The lower barel is brass, threaded on both ends to accept the acorn nozzle and the adapter.
The adapter is aluminum, with fins cut into it to maximize cooling
The entry end is stainless steel, and threads into the adapter.
The result is that the heat gradient over the entire barrel is enough to keep the entry point cool, while the brass part melts the plastic.