The perspective in this note explores rationally defined scaling parameters for injection molding to account for the length and thickness of parts, the melt temperature, the injection pressure, and the injection speed: Injection-molding parameters, first empirically established for 4- to 5-mm-thick parts, were later experimentally optimized for 2- to 3-mm thick parts. The push for even thinner parts required major adjustments in molding technology, including the use of lower-viscosity materials. This shift from thicker to thinner parts was arbitrarily characterized by the length-to-thickness ratio of the part, which is shown to be incorrect.