A system comprises an extrusion head to selectively extrude a bead of a precursor solution onto a target road on a substrate within a build area, the precursor solution comprising a polyimide precursor compound in a solvent, an actuator coupled to the extrusion head to move the extrusion head, a control system coupled to the actuator to control the extrusion head along the target road and selectively dispense the precursor solution to the extrusion head, and an environmental system configured to accommodate the target road during fabrication, the environmental system configured to expose the dispensed precursor solution to a temperature selected to evaporate solvent from the solution to initiate polymerization of the polyimide precursor compound to form at least a portion of a polyimide part.