  The 3D printing process flow requires several inputs for the best printing
quality. These settings may vary from sample to sample, printer to printer, and
depend upon users' previous experience. The involved operational parameters for
3D Printing are varied to test the optimality. Thirty-eight samples are printed
using four commercially available 3D printers, namely: (a) Ultimaker 2
Extended+, (b) Delta Wasp, (c) Raise E2, and (d) ProJet MJP. The sample
profiles contain uniform and non-uniform distribution of the assorted size of
cubes and spheres with a known amount of porosity. These samples are scanned
using X-Ray Computed Tomography system. Functional Imaging analysis is
performed using AI-based segmentation codes to (a) characterize these 3D
printers and (b) find Three-dimensional surface roughness of three teeth and
one sandstone pebble (from riverbed) with naturally deposited layers is also
compared with printed sample values. Teeth has best quality. It is found that
ProJet MJP gives the best quality of printed samples with the least amount of
surface roughness and almost near to the actual porosity value. As expected,
100% infill density value, best spatial resolution for printing or Layer
height, and minimum nozzle speed give the best quality of 3D printing.
