This is my design of an extruder for filament in wire shape. It is designed to precisely extrude plastic wire with 1.75mm in diameter. Extruder will be used on Isel cnc machine capable of driving 2kg spindle with high speed acceleration. Weight wasn’t an obstacle so I made it heavy duty.
I’m using small stepper motor with integrated gearbox which reduces it’s rpm and increases torque. Wire meets the gear with sharp edges which pushed wire further through heat sink to hot end.
Water cooling heat sink That squary thing is actually a water cooled heat sink. The problem with this kind of extruder is that it has to be placed inside the machine where air temperature sometimes reaches 100°C making air cooling impossible. It is also crucial to keep heat sink as cool as possible to reduce chances of filament jamming. On the picture below you can see round and hollow ports/connectors for water pipes/tubes. I applied some thermal paste between water cooler and holder to ensure good thermal conductivity between said parts.
Filament jamming can be easily fixed by simply lifting lever with bearing. Lever is normally pressed down to motor’s gear with constant force supplied by a spring (not shown here).
Next step is going to be hot end with double 40W heaters and changeable nozzle, similar to E3D extruders.
In memory of 2mm endmill tool
One tool died in the process of making parts for this extruder due to my mistake. I feel bad because it was a nice tool, but I also believe it will be treated nicely up there, where it went. Also take a look how how it crushed aluminum. That little piece practically welded to tool shaft (what’s left of it) despite a good amount of coolant being present at the accident place/time.