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Renoir3 extruder

Design

8mm PEEK tube drilled to 3.2mm
All but 15mm re-drilled to 3.5mm

Lower PEEK hole drilled to 4.5mm and M5 tapped

0.6mm Welding tip drilled out to 3.2mm

8Ohm Insulated Nichrome wire wound directly round the welding tip

Heater sealed in fire cement
 
Thermistor leads wrapped in PTFE tape for insulation and embedded in fire cement



Construction

Attach wire to insulated nichrome before building - makes things easier.

From renoir3_extruder
Screw in welding nozzle to PTFE and wind nichrome around tip.
From renoir3_extruder

Cover with fire cement. Added a hose clip to provide extra support (wind to rough dimension and press into wet cement.
From renoir3_extruder
To cure the fire cement, I plugged into the reprap electronics and warmed the heater to 95C. After 20 mins, warmed to 110 for 10 mins, then 130, then 170, then 250. Seemed to work OK.

Pictures

Testing - extruder jammed

If warmed up for a long time (20mins+) and then cooled down with filament left in, has jammed.twice.

Removing filament while hot is a good idea.


Testing - ABS - score 9.9/10


Hand extrusion produces lots of filament very easily.

Best temp for extrusion seems to be about 220C. 240C produces brown filament and starts to 'stick'  - seems to need more force.

Have left this warmed for 3hrs continuous, and seems to be fine so far.

Very little thermal inertia, so warms up quickly.
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