The influence of expedited fabrication rate, unreliable machines, scrap, and rework on the production runtime decision in a vendor-buyer coordinated environment

Transnational manufacturing firms operate in highly competitive marketplaces. This means that they are continuously seeking ways to reduce order response and fabrication cycle times, maintain the desired product quality, manage unanticipated machine failures, and provide timely delivery to effectively minimize overall operating cost and maintain a competitive advantage over their intra-supply chains. To assist firms in achieving these operational goals, we examine a buyer-vendor coordinated system with an expedited fabrication rate, unreliable machines, scrap, and rework, with the objective of minimizing the overall operating costs. An imperfect manufacturing process is assumed, which arbitrarily produces repairable and scrap items, with the latter being reworked in each fabrication cycle. Additionally, the process is subject to a Poisson-distributed machine breakdown. The corrective action is undertaken immediately when the machine fails, and the production of unfinished/interrupted lot resumes when the process is restored. The expedited fabrication rate option is used at an extra cost to reduce the cycle length. We built a fabrication-shipment model to characterize the problem's features explicitly. Mathematical and optimization approaches assist us in determining the optimal fabrication runtime policy. A numerical example illustrates the capability/applicability of our outcomes. Furthermore, it exposes a diverse set of information relating to the collective/individual effect of differences in the expedited rates, mean-time-to-breakdown, frequency of shipment, and rework/disposal rates of defective items on the optimal policy, utilization, total operating cost, and various cost contributors. This information can contribute to facilitating better decision-making.