Cost and Environmental Assessment of Tool Replacement Strategies Under Imperfect Wear Monitoring in Ti6Al4V Milling

The policy for the replacement of cutting tools has a direct influence on the risk of producing out-of-tolerances workpieces, but can also avoid excessive consumption of new tools and production interruption. Current industrial practice tries to achieve an economical balance that does not directly incorporate the environmental impact of the policy. This often results in systematic preventive replacement of tools after a safely fixed number of produced workpieces, wasting a portion of the tool’s useful life (at an environmental cost) and increasing the machine’s downtime. In this study, we simulate the production of Ti6Al4V parts under three different tool replacement scenarios: (1) at fixed intervals, (2) using an imperfect cutting tool monitoring system where the tool can only be replaced between the production of two workpieces, and (3) with a cutting tool monitoring system that allows tool replacement every minute during machining. The simulation demonstrates that even with an imperfect monitoring system, condition-based replacement leads to improved economic performance (expressed in EUR) and environmental performance (expressed in kg CO2-eq). In comparison to systematic replacement, the condition monitoring allows reducing the environmental impact up to 8.7% and the cost up to 8.1%.