Production planning and control for remanufacturing: literature review and analysis

This article reviews the literature on production planning and control (PPC) for remanufacturing. The objectives are threefold: to determine whether the gaps identified by Guide (Guide Jr, V.D.R., 2000. Production planning and control for remanufacturing: industry practice and research needs. Journal of Operations Management, 18, 467–483) on the subject with respect to the main complicating characteristics of remanufacturing have been fulfilled; to classify the literature based on an appropriate structure to obtain a better understanding of the subject identifying sources of future research and to provide a useful source for scholars and practitioners. Seventy-six papers were examined and classified. It was found that none of the studies deals simultaneously with all of the complicating characteristics, and that more practical research is needed. In addition it was found that we lack studies regarding forecasting and aggregate planning considering disassembly of returned products, material matching restrictions or stochastic routings, master production scheduling considering material matching restrictions or stochastic routings, ordering system and capacity planning considering material matching restrictions and inventory control and management considering stochastic routings.     

Production planning and control for remanufacturing: exploring characteristics and difficulties with case studies

Production planning and control for remanufacturing is a major managerial challenge in the operations management. Researches demonstrate the need for decision-making methods in this context, which has generated theoretical and quantitative studies. However, this area still lacks empirical studies dealing with the practical, day-to-day difficulties of remanufacturers. The purpose of this paper is to link the literature and practice in a systematic in such a way that it is possible to show the similarities and differences between theoretically listed needs and real cases, thereby extending the results of previous research. For this purpose, four case studies are considered. The cases involve original equipment manufacturers (OEM) of automotive parts that have remanufacturing operations. The results indicate that these companies have difficulties that have not been addressed to date in the literature related to the uncertainties inherent in remanufacturing. In addition, we find that these companies use simplified decision-making approaches.     

外包再制造下再制造设计对制造 /再制造影响

为分析外包再制造模式下,再制造设计对制造/再制造供应链竞争的影响,构建制造/再制造博弈模型.基于博弈模型,分析再制造设计费用不同承担方式对再制造设计努力程度、废旧产品回收率、收益和环境等影响.研究结果表明:原始制造商通过外包再制造不仅可以降低再制造商的市场竞争优势,还可以获得再制造带来的收益;再制造设计可以促进再制造商回收废旧产品,提高废旧产品回收率;无论是原始制造商还是再制造商承担再制造设计费用,两者收益分别在再制造设计努力程度的不同点达到最大,而不是再制造设计努力程度越大其收益越大;再制造对环境影响并不总是有利的,当单位再制造产品与新产品对环境造成的影响之比小于某一阀值,同时再制造设计给单位再制造产品带来收益与带给单位新产品收益之比大于某一阀值时,再制造才有利于降低对环境的影响.     

偏好市场下制造 /再制造系统最优生产决策

从消费者对再制造产品和新产品有着不同的需求偏好入手, 引入市场需求偏好函数, 构建单一垄断生产商利润最大化的带约束生产决策模型, 探讨偏好市场下的两期和无限期的最优产量 -价格决策策略.此外, 通过对再制造经济优化模型的数据模拟, 分析消费者偏好系数对生产商利润、成本节约、产品价格的影响, 为生产商的生产决策, 以及政府如何影响消费者偏好决策提供指导建议     

偏好市场下制造/再制造系统最优生产决策

从消费者对再制造产品和新产品有着不同的需求偏好入手,引入市场需求偏好函数,构建单一垄断生产商利润最大化的带约束生产决策模型,探讨偏好市场下的两期和无限期的最优产量-价格决策策略.此外,通过对再制造经济优化模型的数据模拟,分析消费者偏好系数对生产商利润、成本节约、产品价格的影响,为生产商的生产决策,以及政府如何影响消费者偏好决策提供指导建议.     

Lot Sizing for Optimal Collection and Use of Remanufacturable Returns over a Finite Life‐Cycle

Reverse supply chains process used product returns to recover value by re‐processing them via remanufacturing operations. When remanufacturing is feasible, the longer the return flows are delayed during the active (primary) market demand period of the product, the lower the value that can be recovered through these operations. In fact, in order to recover the highest value from remanufactured products, the collection rates, return timings, and reusability rates should be matched with the active market demand and supply. With these motivations, this paper is aimed at developing analytical models for the efficient use of returns in making production, inventory, and remanufacturing decisions during the active market. More specifically, we consider a stylistic setting where a collector collects used product returns and ships them to the manufacturer who, in turn, recovers value by remanufacturing and supplies products during the active market demand. Naturally, the manufacturer's production, inventory and remanufacturing decisions and costs are influenced by the timing and quantity of the collector's shipments of used product returns. Hence, we investigate the impact of the timing of returns on the profitability of the manufacturer‐collector pair by developing system‐wide cost optimization models. Analyzing the properties of the optimal shipment frequency, we observe that the fastest reverse supply chain may not always be the most efficient one.     

Uncertainty,flexibility and buffers in the management of the firm operating system

The role that buffers can assume in the management of uncertain situations that can occur in industrial firms is demonstrated. An outline is provided of the various types of buffers with regard to different types of uncertainty faced and to the characteristics of the production system. Although the prevalent scholarly trend is to evaluate buffers as factors which uselessly increase the complexity of the firms operating systems, this work tries to analyse the contributions they offer to the management process. Buffers are considered as alternative and complementary factors to technological flexibility. Technological flexibility is often considered the only competitive means able to face both external and internal uncertainties. The choice to use or not use buffers as a complementary resource or as an alternative to technological flexibility, depends on a comparison of the cost-benefits of the two solutions     

The Value of Quality Grading in Remanufacturing

In this paper we consider a tactical production‐planning problem for remanufacturing when returns have different quality levels. Remanufacturing cost increases as the quality level decreases, and any unused returns may be salvaged at a value that increases with their quality level. Decision variables include the amount to remanufacture each period for each return quality level and the amount of inventory to carry over for future periods for both returns (unremanufactured), and finished remanufactured products. Our model is grounded with data collected at Pitney‐Bowes from their mailing systems remanufacturing operations. We derive some analytic properties for the optimal solution in the general case, and provide a simple greedy heuristic to computing the optimal solution in the case of deterministic returns and demand. Under mild assumptions, we find that the firm always remanufactures the exact demand in each period. We also study the value of a nominal quality‐grading system in planning production. Based on common industry parameters, we analyze, via a numerical study, the increase in profits observed by the firm if it maintains separate inventories for each quality grade. The results show that a grading system increases profit by an average of 4% over a wide range of parameter values commonly found in the remanufacturing industry; this number increases as the returns volume increases. We also numerically explore the case where there are capacity constraints and find the average improvement of a grading system remains around 4%.     

闭环供应链下再制造生产计划研究述评

再制造是实现循环经济"减量化、再利用、资源化"三原则的重要途径。再制造生产活动中,计划扮演着重要的先行角色。本文根据再制造系统的回收和拆卸特色,先讨论与再制造生产计划有关的几个重要参数;然后从再制造生产计划的结构层次入手,对再制造生产计划领域的研究进展进行探析;最后指出目前研究不足之处以及未来研究的可能方向。     

Experimental push/pull production planning and control system

We introduce an experimental push/ pull production planning and control software system which is designed as an alternative to a MRP-II system for mass manufacturing enterprises in China. It has the following distinguishing features: (1) putting the philosophy of JIT into the master production scheduling of MRP-II via the earliness/ tardiness production planning method; (2) controlling material input by push and processing/ assembly by pull; and (3) adjusting the parameters of the production line by the‘ suggestion for improvement of production line’ module. Simulation results have shown that the proposed system can achieve better planning and control performance than existing systems.     

Dynamic performance of a hybrid inventory system with a Kanban policy in remanufacturing process

In this paper we study a hybrid system with both manufacturing and remanufacturing. The inventory control strategy we use in the manufacturing loop is an automatic pipeline, inventory and order based production control system (APIOBPCS). In the remanufacturing loop we employ a Kanban policy to represent a typical pull system. The methodology adopted uses control theory and simulation. The aim of the research is to analyse the dynamic (as distinct from the static) performance of the specified hybrid system. Dynamics have implications on total costs in terms of inventory holding, capacity utilisation and customer service failures. We analyse the parameter settings to find preferred “nominal”, “fast” and “slow” values in terms of system dynamics performance criteria such as rise time, settling time and overshoot. Based on these parameter settings, we investigate the robustness of the system to changes in return yield and the manufacturing/remanufacturing lead time. Our results clearly show that the system is robust with respect to the system dynamics performance and the remanufacturing process can help to improve system dynamics performance. Thus, the perceived benefits of remanufacturing of products, both environmentally and economically, as quoted in the literature are found not to be detrimental to system dynamics performance when a Kanban policy is used to control the remanufacturing process.     

Inventory Rationing in a Make‐to‐Stock System with Batch Production and Lost Sales

We address an inventory rationing problem in a lost sales make‐to‐stock (MTS) production system with batch ordering and multiple demand classes. Each production order contains a single batch of a fixed lot size and the processing time of each batch is random. Assuming that there is at most one order outstanding at any point in time, we first address the case with the general production time distribution. We show that the optimal order policy is characterized by a reorder point and the optimal rationing policy is characterized by time‐dependent rationing levels. We then approximate the production time distribution with a phase‐type distribution and show that the optimal policy can be characterized by a reorder point and state‐dependent rationing levels. Using the Erlang production time distribution, we generalize the model to a tandem MTS system in which there may be multiple outstanding orders. We introduce a state‐transformation approach to perform the structural analysis and show that both the reorder point and rationing levels are state dependent. We show the monotonicity of the optimal reorder point and rationing levels for the outstanding orders, and generate new theoretical and managerial insights from the research findings.     

A simulation testing and analysis of aggregate production planning strategies

In this study, a hybrid discrete event simulation (DES) and system dynamics (SD) methodology is applied to model and simulate aggregate production planning (APP) problem for the first time. DES is used to simulate operational-level and shop-floor activities incorporated into APP and estimate critical time-based control parameters used in SD model of APP and SD is used to simulate APP as a collection of aggregate-level strategic decisions. The main objective of this study is to determine and analyse the effectiveness of APP strategies regarding the Total Profit criterion by developing a hybrid DES–SD simulation model for APP in a real-world manufacturing company. The simulation results demonstrated that the priority of APP strategies with regards to Total Profit criterion is: (1) the pure chase strategy, (2) the modified chase strategy, (3) the pure level strategy, (4) the modified level strategy, (5) the mixed strategy and (6) the demand management strategy, respectively. The APP system is first simulated under mixed strategy (basic scenario) conditions to include all APP capacity and demand options in constructed SD simulation model to show a comprehensive view of APP components and their interdependent interactions. Then, the obtained results will be used as Total Profit measure to compare with system's performance under some experimental scenarios applying different APP strategies.     

废旧产品回收再制造计划模式研究述评

在分析再制造基本概念及流程的基础上,从废旧产品回收计划、回收产品拆卸计划、再制造生产计划等三个方面对国内外再制造计划模式的研究现状进行综述。指出目前研究中对再制造过程的不确定性特征认识不足、对产品回收后的状态不能有效预测、对不确定情形的产品拆卸计划研究较少、对于再制造生产计划与控制缺乏系统研究。针对上述不足,提出了进一步研究的方向。     

考虑质量成本的再制造系统批量计划综合优化

研究需求和再制造率不确定下整个再制造系统的综合协调问题,帮助再制造商制定各环节批量决策以实现整体最优． 首先,考虑对应其拆卸后不同质量状况的差异再制造成本,构建能反映质量成本的拆卸和再制造总成本模型; 接着,考虑新零部件采购提前期,利用两阶段利润函数的思想,构建包括拆卸、再制造和重新装配3个子系统中所有成本因素、以利润最大化为目标的优化模型; 然后,求解最优再制造/拆卸比率、拆卸批量、再制造/采购批量和重新装配批量; 最后,通过算例验证并讨论平均再制造零部件获取成本对再制造批量、采购批量、拆卸和再制造总成本以及总利润的影响,再制造/拆卸比率和单位拆卸成本的关系．     

Production planning and control as a tool for eco-efficency improvement and environmental impact reduction

The environmental impacts of industrial activity are an increasing concern amongst firms and their stakeholders. As a result, companies around the world have been exploring new tools to diminish the adverse impact of their activities on the environment. Eco-efficiency has played an essential role in this scenario, as companies are continuously seeking to produce more while utilizsing fewer resources and minimising adverse effects on the environment. The literature includes several initiatives to improve eco-efficiency and to reduce the environmental impact of manufacturing operations, but the use of production planning and control (PPC) activities to accomplish these goals has rarely been considered. Therefore, to contribute to the assessment of this issue, this paper proposes to integrate environmental concepts and actions as part of the PPC execution; therefore, they could also be applied to minimise environmental impacts, resulting in an increase in the eco-efficiency level of a company. The practical utilisation of the suggested procedure was confirmed using a case study where the procedure was successfully applied to a make-to-order firm, where a simplified version of a workload control (WLC) form of PPC was in use. As a result, incorporating environmental considerations into the WLC practices enabled the eco-efficiency level of the designated production area to increase by 42%, while the environmental impact of production was reduced by 13%.     

Group technology and growth at Shalibane

Abstract. The Shalibane Company of Camberley are tube manipulators and sheet metal workers, making parts mainly for the car industry. In 1991 they introduced Group Technology (GT). In eighteen months they reduced stocks by 60% (still falling); increased sales and output by 33%; increased the rate of return on investment by 24%; and increased the number of their employees by 12%. The cost of introducing the change was covered more than 3 times by the reduction in the stock investment. GT is shown to be a method which promotes growth and increases productivity, profitability and employment.     

Optimal Production and Admission Policies in Make‐to‐Stock/Make‐to‐Order Manufacturing Systems

In this article, we study optimal production and admission control policies in manufacturing systems that produce two types of products: one type consists of identical items that are produced to stock, while the other has varying features and is produced to order. The model is motivated by applications from various industries, in particular, the automobile industry, where a part supplier receives orders from both an original equipment manufacturer and the aftermarket. The product for the original equipment manufacturer is produced to stock, it has higher priority, and its demands are fully accepted. The aftermarket product is produced to order, and its demands can be either accepted or rejected. We characterize the optimal production and admission policies with a partial‐linear structure, and using computational analysis, we provide insights into the benefits of the new policies. We also investigate the impact of production capacity, cost structure, and demand structure on system performance.     

基于改进策略的混合型制造/再制造系统分析

在制造和再制造并存的混合型系统中,制造商需要同时协调新产品生产过程和旧产品再制造过程,这种双向物流的集成运作使得传统的生产规划和库存管理方式不再适用,如何构建一种有效的控制策略来协调生产过程和再制造过程就显得十分关键。本文在优化库存信息的基础上提出了一种适用于混合系统的改进策略,同时考虑到系统复杂性,主要采用控制理论中的传递函数技术构建了系统模型。仿真结果表明,本文提出的改进策略不仅可以有效协调新产品生产过程和旧产品再制造过程,而且还可以显著改善系统性能。     

Managing Production and Distribution for Supply Chains in the Processed Food Industry

We develop and evaluate a modeling approach for making periodic review production and distribution decisions for a supply chain in the processed food industry. The supply chain faces several factors, including multiple products, multiple warehouses, production constraints, high transportation costs, and limited storage at the production facility. This problem is motivated by the supply chain structure at Amy's Kitchen, one of the leading producers of natural and organic foods in the United States. We develop an enhanced myopic two‐stage approach for this problem. The first stage determines the production plan and uses a heuristic, and the second stage determines the warehouse allocation plan and uses a non‐linear optimization model. This two‐stage approach is repeated every period and incorporates look‐ahead features to improve its performance in future periods. We validate our model using actual data from one factory at Amy's Kitchen and compare the performance of our model to that of the actual operation. We find that our model significantly reduces both inventory levels and stockouts relative to those of the actual operation. In addition, we identify a lower bound on the total costs for all feasible solutions to the problem and measure the effectiveness of our model against this lower bound. We perform sensitivity analysis on some key parameters and assumptions of our modeling approach.