We previously proposed a Consumption Performance Sustainability Index to assess the sustainability of additive manufacturing products made by Fused Filament Fabrication. For simplicity and to get broader applications, the index was defined as dimensionless and composed of several factors related to the manufacturing process. The index included material and energy consumption and the performance of the transformed material, which, in the last case, was measured as the yield or the maximum resistance of the produced part in comparison with the characteristics of the feedstock material. The index can highlight the most sustainable among other solutions based on different print orientations and part densities. We propose extending the Consumption Performance Sustainability Index’s validity to additive manufacturing and Computerized Numerical Control (CNC) machining processes. For this purpose, each factor has been revised and, if necessary, expanded to include process parameters of machining processes. A new organization of all the factors has been introduced based on groups of parameters related to material properties and usage, part design, consumed energy, and machine time. Case studies have been investigated to evaluate this new index for assessing product sustainability preliminarily.