Minimising carbon emissions and machining costs with improved human health in sustainable machining of austenitic stainless steel through multi-objective optimisation

Environmental and societal concerns have fuelled an ever growing need for more sustainable products and machining processes. Much research has been focused on this issue in aviation, automotive, and medical industries where austenitic stainless steels have been often used. During machining of these materials, high cutting forces and carbon emissions make the machining process significantly more challenging. Therefore, in this study sustainable orthogonal turning experiments were conducted using dry cutting, MQL, and cryogenic cooling at different cutting speeds and undeformed chip thicknesses. Experimental cutting forces were measured and used to analytically determine the carbon (CO₂) emissions. In order to determine the optimal machining parameters for minimising the CO₂ emissions and the overall economic cost with improved human health conditions, a multi-objective optimisation problem was established. The optimal machining parameters were determined to be a cutting speed of 100 m/min and undeformed chip thickness of 0.12 mm, while using cryogenic cooling.