On how buyback and remanufacturing strategies affect the profitability of spare parts supply chains

The purpose of this paper is to provide a case-based framework to offer insights on the opportunity of recovering parts. We consider a two-stage spare parts supply chain, where independent repair shops are responsible for handling the repair process. There are two options to meet spare parts demand: repair shops may replace the part with a new one (ordered from the OEM) or they may use a part that they themselves repaired before. While repair shops achieve a larger profit by repairing parts, the OEM would prefer the use of new parts. However, he has no control over demand which might be obtained by offering buyback of broken parts. Furthermore, the OEM could recover these parts on a higher level, thus reducing production/procurement of new parts. The main contribution of this paper is the provision of a simple deterministic framework for answering the question whether a buyback option should be offered by the OEM to the repair shops, and which buyback price should be paid for each returned core. We further highlight the impact of remanufacturing performed at the OEM on the profitability of buyback.     

Improving global spare parts distribution chain performance through part categorization: A case study

Spare parts inventory management is a complex problem and in most cases part categorization is needed to create a manageable number of control groups to focus management efforts more effectively. Usually multi-dimensional or multi-criteria classifications are used, and there are several examples of classification schemes available in the literature. The complexity increases even more when taking into consideration that a distribution chain consists of many parties. Thus, in addition to internal inventory control factors, external factors such as supplier performance, customer behavior and related demand patterns affect the controllability of the various parts.In the paper we try to expand existing classification schemes that cover only one part of the supply chain into a decision tool covering three sides of the chain: the company's distribution center with its internal processes, supplier with supply processes and customer with demand processes. The complexity that is created by the expanded view is reduced by considering two separate links: demand link and supply link. At first the links are analyzed separately considering the most relevant factors of each one and afterwards they are combined into a categorization matrix to classify the parts.The categorization scheme is tested in a large international company for improving its spare parts distribution chain performance. In the case company's demand link, part value and demand variability were used as the factors to create seven categories. In supply link, three categories are created by using availability risk of the material as the categorizing factor. The spare parts distribution chain performance is analyzed with service performance and stock-out cost key performance indicators before and after improvement actions. Finally, it is discussed how widely the insights from the case experience can be generalized towards developing a generic management tool for such a complex situation.     

河北省汽车及零部件出口存在的问题与对策

一个国家汽车工业的发展水平,在一定意义上可以折射出这个国家的综合实力水平。河北省汽车工业生产及产品出口的形势,虽然在过去的几年里有较快的发展,但有些方面的问题也不容忽视。就企业规模、产品档次、技术服务以及政策支持等方面的问题进行了较为深入的调查分析,提出了初步的应对策略。     

Inventory ordering policies of delayed deteriorating items under permissible delay in payments

The existing literature on inventory of deteriorating items considers deterioration to begin as soon as the items are stocked. However, there are several deteriorating items that do not start deteriorating immediately they are held in stock. Some farm produce like potatoes, yams and even some fruits and vegetables have this property. Depletion of these items as soon as they are stocked will depend on demand, and when deterioration begins, it will depend on both demand and deterioration. In this paper, we develop a mathematical model on the inventory of deteriorating items that do not start deteriorating immediately they are stocked. The model also takes into cognizance the fact that in business activities nowadays customers are given some allowed period within which to settle for the goods supplied to them. They can use the accrued money from sales of the supplied goods to earn interest within the allowed period. They are charged interest only when they fail to settle the amount they owe the supplier at the end of the allowed period.     

Exact and approximate calculation of the cycle service level in periodic review inventory policies

The parameters of stock policies are usually determined to minimize costs while satisfying a target service level. In a periodic review policy the time between reviews can be selected to minimize costs while the order-up-to-level is based on the fulfilment of a target service level. Generally, the calculation of this service measurement is obtained using approximations based on an additional hypothesis related to the demand pattern. Previous research has shown that there is a substantial difference between exact and approximate calculations in some general circumstances, so in these cases the service level is not accomplished or the stock level is overestimated. Although an exact calculation of CSL was developed in previous work, the computational effort required to apply it in practical environments leads to the proposal of two approximate methods (PI and PII) that, with the classic approximation, are analysed and evaluated in this paper. This analysis points out the risks of using the classic approximation and leads one to suggest PII as the most suitable and accurate enough procedure to compute the CSL straightforwardly in practice. Additionally, a heuristic approach based on PII is proposed to accept or reject an inventory policy in terms of fulfilling a given target CSL. This paper focuses on uncorrelated, discrete and stationary demand with a known distribution pattern and without backlog.     

A heuristic for balancing the inventory level of different locations through lateral shipments

Solving transshipment problems to optimality is difficult, unless several simplifying hypotheses are assumed (such as unit-sized customer demands and replenishments, negligible replenishment lead time, etc.). For this reason, some heuristics have been recently proposed in order to provide rules, which incorporate relevant factors of the problem, to find conditions under which it makes sense to transship a certain number of units from one retailer to another. Most of these studies concern emergency transshipment, which means that shipments between locations can occur only when a shortage happens, and shipments are assumed to be fast enough to satisfy the location in shortage. When this assumption is not feasible, as in many real cases, transshipments between locations have to be performed before a shortage happens. The paper addresses this case, which can be named ‘preventive’ transshipment, where the inventory level of different locations at the same echelon is balanced through lateral shipments, before a shortage happens. A heuristic for deciding on transshipment policy (when to transship and how much), trying to minimise overall expected costs, is presented. A simulation study considering different scenarios is performed and results confirm the effectiveness of the heuristic.     

Evaluation of postponement in the soluble coffee supply chain: A case study

This paper, through a case study, evaluates postponement as an option to improve supply chain performances in a soluble coffee manufacturer. The main focus of the paper is on the development of a numerical data-driven methodology for quantifying the benefits of postponement obtained from the total inventory reduction. Our study shows that significant cost savings are achievable by delaying the labelling and packaging processes until actual orders from retailers are known. These savings include the reduction of the cycle stock, safety stock, and obsolete stock unsold from promotional events. We also discuss the cost implications of the proposed configuration that may offset the estimated potential benefits. The methodology presented in this paper can also be used in many other supply chains, particularly in the food industry with similar environments. This paper contributes to the literature in extending the very short list of published work presenting a systematic methodology of characterising the postponement benefits in real world settings and driven by numerical data.     

Assessing the influence of the organization in the supply chain management using NK simulation

Supply chain management advocates that the whole supply chain (SC) from the material suppliers to the end customers must be managed by adopting an integrated approach. However, different forms of governance can be adopted to pursue integration, ranging from the pure market to the hierarchy. While integration has been extensively investigated in the literature by adopting an operative perspective, the organizational perspective has been less used. However, the way the SC is organized influences the SC performance. This topic is investigated by using a recent tool offered by complexity science, namely the NK simulation model. In the proposed NK model, N represents the decisions that SC firms should make and K the interdependencies among the SC decisions calling for integration. The model reproduces how the different SC forms of governance evolve and adapt to the landscape corresponding to a SC specific integration problem. A simulation analysis is carried out to identify the SC forms of governance appropriate to the SC integration problems.