3 ms·
Fundamentally, if the nozzle temperatures can't possibly withstand what they are extruding without eroding, we can either: - balance an exothermic reaction (se
by positron26 11mo ago
Fundamentally, if the nozzle temperatures can't possibly withstand what they are extruding without eroding, we can either:
- balance an exothermic reaction (self-propagating high-temperature synthesis) to occur just after leaving the nozzle
- externally apply the heat with laser or plasma arc etc
The limit of externally applying heating is when the heat flux has to be so high that some material vaporizes and pops. An exothermic reaction within the material overcomes this limitation.
- jaggederest 11mo agoThe other alternative is like current state of the art 3d printing ceramics - you either replace some high percentage of the filament with clay and fire it as a post processing step and it burns off the plastic, or print a clay/water slurry directly and fire it after drying. But I don't think we'd end up with the basalt being very filamentous.
- positron26 11mo agoIf the binder that gives you something printable at low temperature doesn't integrate into the final result through chemical reaction, you are almost assuredly going to get a high porosity mess where the binder had to vaporize out. If instead the binder and precursor can melt, react, and expand into a solid that precipitates out because of a super high melting point, the expansion will ensure that you get a fully dense part that can be machined back down.