3-D Printing is never identically re-oriented each time for the same product. The lay of the material that is the bed for the laser sintering is uniform but never "exactly" the same; therefore, all 3-D printed products of the same item are actually one of a kind! (hence the term Stereo Lithograph... Original creation from a computer file.) The products is made of hundreds if not thousands of layers. Original pieces that usually cannot be mass produced by injection molding Or where injection molding is not preferred.