We consider a hybrid manufacturing/remanufacturing system where the returned products (cores) are classified into different quality grades. Each grade requires different remanufacturing operations and thus lead times. We examine the implications of the quality-grading scheme on the dynamic behavior of closed-loop supply chains, benchmarking this against a typical system where all the returns undergo the same remanufacturing process. Through control engineering techniques, we evaluate the Bullwhip and inventory performance of the supply chain by observing the step response of the orders and net stocks (the shock lens), analyzing the frequency behavior of these signals (the filter lens), and measuring their dynamics due to stochastic demand (the variance lens). Subsequently, we discuss the operational savings and additional costs derived from quality grading. We find that the pre-sorting mechanism allows for smoothing the supply chain operations; however, its impact on customer satisfaction is ambivalent. Indeed, we observe that the documented ‘lead-time paradox’ of the remanufacturing process in hybrid systems results here in a ‘quality paradox’: lower quality returns may increase the performance of inventories. This affects particularly low-frequency demands. Importantly, we analytically derive the optimal setting of the closed-loop pipeline estimation in order-up-to policies for avoiding long-term inventory drifts. This analysis reveals key potential benefits of information transparency for improving the operational performance, and thus the environmental and economic sustainability, of closed-loop supply chains.

我们考虑一种混合制造/再制造系统，在该系统中，退货产品（芯）被分类为不同的质量等级。每个等级都需要不同的再制造操作，因此需要交货时间。我们研究了质量分级方案对闭环供应链动态行为的影响，并以一个典型的系统为基准，在该系统中，所有退货都经过相同的再制造过程。通过控制工程技术，我们通过观察订单和净库存的阶跃响应（震荡透镜），分析这些信号的频率行为（滤镜）并评估其动态来评估供应链的牛鞭和库存表现。由于随机需求（方差镜片）。随后，我们讨论了运营节约和质量分级所带来的额外成本。我们发现预分类机制可以使供应链运作更加顺畅。但是，它对客户满意度的影响是模棱两可的。实际上，我们观察到混合系统中再制造过程的书面“提前期悖论”在这里导致了“质量悖论”：较低的质量收益可能会提高库存的绩效。这会影响特别低的频率需求。重要的是，为了避免长期存货漂移，我们从政策上分析得出了闭环管道估算的最佳设置。此分析揭示了信息透明性对于改善运营绩效以及环境和经济可持续性的关键潜在好处，