I'm a ceramic engineer and i wrote my Masters thesis about the extrusion of Al2O3 and MoSi2. For that purpose i developed a progressive cavity pump, capable of extruding two materials.
If anyone is interested i upload my design here.
The pump i used needs to be casted out with Silicon or any other flexible material.
I can also upload the design with the inner cavity already printed, but I'm not sure if this one will work.
I have two different inlet-designs. One witch uses a Moineau-like design and the other one has the Inlet (similiar to a WASP Clay Extruder with a screw) further down, meaning the Rotor is already visible in the infeed.
I'm sorry for any bad explanations, English is not my first language so if i should explain something further just ask.
If anyone is interested in my design i will upload it.
It didn't work flawlessly, but i managed to print an electrical conductive Material side by side with an electrical insulator.