Evaluation of mixed-model U-line operational designs

Often in lean manufacturing, multiple products are produced in U-shaped manufacturing cells to simultaneously achieve product variety and production efficiency. We examine two design issues for mixed-model U-lines: work rules (a first-come-first-serve rule and a crossover-and-return rule) and inventory flow choices (direct flow and buffered flow). Simulation results indicated that throughput and labor utilization can be improved by implementing a “buffer” with the first-come-first-serve rule. Interestingly, the effectiveness of an inventory flow choice was dependent on the work rule (interaction effect), and relationships among performance dimensions differed across the designs.