Figure 1. Top left, microextrusion of an 8% volume fraction carbon fiber loaded bisphenol-F resin ink from a 600 μm straight tip nozzle under a constant driving pressure.

The average fiber thickness and lengths were 6 and 300 μm respectively. Note that the carbon fiber loaded ink will flow as a contiguous fluid under pressure at measured volumetric flow rates of 7.4 × 10⁻⁴ cm³ min due to the shear thinning behavior of the resin phase and the efficient shear alignment of the high aspect ratio fiber phase during printing. The ink rapidly solidifies on extrusion to form self-supporting filaments on the size scale of the extrusion nozzle tip (top right) which may be built up from a base substrate into 3D structures, shown here is an open cell 0, 90 arrangement with an average filament diameter of 600 μm and that was subsequently thermally cured to yield a robust CF composite with a nominal 50% porosity. (Lower) micrographs of y-z plane (left) and x-y plane (right) sections of the printed and cured AMCRFC part. It can be noted from both images that we achieve both a high degree of control of the micro-architecture of the part and the relative alignment of the fiber-phase within individual filamentary extrudates.