Optimizing Manufacturing Processes through the Integration of Dynamic Job Shop Scheduling and Maintenance Planning

This study integrates the Dynamic Job Shop Scheduling Problem (DJSSP) with maintenance planning to optimize manufacturing processes. The model minimizes makespan while accounting for the uncertainty of job arrivals and machine maintenance. Analysis revealed a minimum makespan of 753.31 hours and a tardiness of $\mathbf{1 3 9 1. 4 2}$ hours before a new job, which increased to a makespan of $\mathbf{8 1 3. 3 1}$ hours and a tardiness of $\mathbf{1 6 8 9. 4 4}$ hours afterward. Compared to the existing estimation makespan of 835.81 hours, the proposed model shows significant improvement up to $\mathbf{9. 8 \%}$. Optimal preventive maintenance intervals, based on minimizing Total Expected Maintenance Cost (TEMC), varied for each component due to their non-identical component. This approach enhances machine reliability and extends equipment life, delaying the need for replacements. The results demonstrate significant improvements over existing methods that use unplanned maintenance schedule.