On Sustainability Assesment of Machining Processes

There is an increased interest in sustainability assessment of manufacturing systems and processes because of the growing global interest in sustainable manufacturing practices. The current sustainability assessment models present a holistic approach, e.g. LCA, without much focus on process specific details. This paper uses a ‘XSI’ approach for defining sustainability indices (e.g. Energy Sustainability Index, ESI). These sustainability metrics can quantify machining processes in terms of impact on the environment and power consumption in a flexible manner, so that various material removal processes can be rated on a uniform scale. In addition, the concept of Normalization, with respect to the ‘feature-of-interest’ is introduced, thus presenting a flexible rating system in terms of process types (turning, milling etc.) and perspectives (material removal, quality etc.). A user-friendly calculator is developed, which converts a set of inputs for the machining scenario into a set of measurable rating quantities and indices including but not limited to production rate, production cost, tool life/cost, energy consumption and environmental burden. This will enable the manufacturing engineer to make an informed decision about parameter selection and process design for sustainability. Machining of hard-to-machine materials such as Titanium Alloys is such a scenario, which is used as a case study to validate the proposed approach.