Optimal buffer sizes and inspection station positions in unreliable non-homogeneous production lines

The interaction between production management and quality management is crucial to ensuring high-quality products and maintaining customer satisfaction. In manufacturing settings, quality control and inspection stations are typically implemented on production lines to prevent the dispatch of defective products. This study explores the integration of additional inspection stations into a manufacturing line to minimize overall costs and improve operational efficiency. The non-homogeneous manufacturing line studied in this article consists of unreliable machines, inventories, and inspection stations. The goal is to minimize the long-term average cost per unit of time, which includes both storage costs and inspection costs. To solve the optimization problem, the study employs dynamic programming and demonstrates the approach with an illustrative example. The results suggest that a more complex optimal configuration, balancing inspection and storage needs, leads to better overall cost efficiency. • Unreliable non-homogeneous production lines with inspection stations were proposed. • Decomposition/aggregation and dynamic programming methods were used. • Optimal buffer sizing and inspection station positioning were studied. • Minimizes cost of storage, shortage, and inspection via optimization. • Scalability tested with up to 20-machine configurations. • Total cost is convex relative to the number of inspection stations.