Peek or PTFE
Benifit of Peek
no dangerous fumes if over heated.
I have 16mm diameter PEEK rod.
Disadvantages of PTFE
dangerous fumes if over heated
I dont have any PTFE.
The Original Reprap Mendel design:-
New Idea for a PEEK version of the insulator.
Diffrence from original.
1/ The top of the insulator is D shaped.
2/ The insulator mounts through a 6mm thick D Shape hole to stop twisting.
3/ The insulator is held in place with an E clip
4/ The filament clearance hole is bigger at 4.2mm
5/ The heated barel threaded length is much shorter.
6/ The heated batrrel is 25mm long
Calculations for the thermal insulation of these insulators calculated here given these constatnts.
PEEK = Thermal resistance 0.25 W/m.K
PTFE = Thermal resistance 0.25 W/m.K
ABS = Thermal resistance 0.188 W/m.K
PLA = Thermal resistance ???? W/m.K
Air = Thermal resistance 0.025 W/m.K
But the thermal resistance of PTFE changes at 232°C. exert taken from http://www.sump4.com/publications/conf015.pdf
"CONCLUSIONS A simple and accurate apparatus for the determination of thermal conductivity was built and used to investigate the effect of processing and composition on the heat transport behavior of PTFE/glass fiber mats. Ancillary measurements indicated that the thermal conductivity of PTFE increased with increasing crystallinity at 232°C."