A new need for safety stocks in a supply chain dedicated to customized mass production.

In a supply chain designed for the production of goods of wide variety, the production schedule creates an ordered list of all the alternate components that will be mounted on a same post of the chain. The supply of these components by the supplier may induce transportation-related constraints. There from systematically follows a time-gap between orders and deliveries. This mechanism, commonly called “rank-change”, may be analyzed with the help of the multinomial distribution associated to these alternate components; only a simulation approach has relevance as of that matter, for an analytic approach is not possible. Such an analysis allows assessing the importance of the need to form safety stocks because of the lot sizing, even though requirements are certain.stock de sécurité; lotissement dans transport; chaîne logistique;

Synchronization and decoupling of plants piloting in a supply chain dedicated to customized mass production.

The synchronization of the production of a manufacturing supplier, who makes alternate components assembled on his industrial customer’s work station with this client’s production specialized in mass production of highly diversified products, must take into account the improvement of their knowledge of the final demand (displacement of the Order Penetration Point) and the distance of some of the suppliers. The customer periodically forwards firm orders to his supplier calculated so as to preclude any production line stoppage. It is necessary that the supplier honor them to ensure the decoupling of the control of these two entities in the supply chain and define the efficiency of synchronization. In the considered context, the supplier also receives all available projected information from the industrial customer (final orders, firm on the short term, and structural characteristics of the final demand beyond). The efficiency of the supplier depends on the proper use of all information, notably when the production cycle of alternate components is longer than the demand cycle. In the study of the customer’s requirements, it is necessary to take into account the batch constraints linked to transportation, which compels the customer to hold safety stocks even though the set up organization guarantees that orders will be duly honored. The determinants of these stocks will be put in evidence. Similarly at the supplier, safety stocks will be necessary if the production process involves grouping in batches.synchronisation de la production dans une chaîne logistique; stock de sécurité; chaîne logistique;

A process oriented approach to service concepts.

Cet article s’intéresse à l’amélioration de la qualité des services et à leur conception en discutant des concepts classiquement mobilisés dans l’analyse des services, au travers d’une approche orientée processus. Il commence par passer en revue les définitions proposées par quelques chercheurs bien connus, spécialistes des services. Il propose une nouvelle typologie des service basée sur une approche orientée processus, permettant de discuter la portée de certaines caractéristiques généralement associées aux services. Il pointe ensuite les similitudes existant entre la production de biens et celle de services et traite du continuum biens-services. Il s’intéresse enfin au clivage des opérations réalisées en front office et en back office, l’explicitation de la ligne de partage permettant de discuter de la qualité de service du double point de vue du consommateur et du producteur, dans une perspective de conception d’un service.The authors aim to contribute to the research on improvement of service quality and on service design by discussing service concepts through a process oriented approach. They begin by reviewing the service definitions given by some well known researchers working on service. They propose a new process oriented service classification which helps to challenge the validity of some service characteristics. They point out similarities between manufacturing and service production and discuss good-service continuum. They focus on separation of back-office operations from the front-office operations by the line of visibility which may help to discuss service quality from both producer's and customer's perspective in a service design context.Management de la production de services; Définition d'un service; Continuum produits-services; Classification des services; Coproduction;

Scheduling Coordination in a Supply Chain Using Advance Demand Information.

In an environment of mass customization where demand information can be placed in advance with sequencing orders, the question of the best use of this information arises in a supply chain. This situation led the authors to analyze the efficiency of current mechanisms of scheduling coordination when suppliers' processes are not completely reliable. Policies such as periodic replenishment or the kanban system, characterized by a replacement of the items to consume, cannot be exploited effectively with the current rules. This paper presents and justifies new scheduling coordination rules allowing synchronous production in an unreliable environment. This new approach has been benchmarked in the automotive industry as an appropriate method to avoid stockouts and decrease the safety stock.Chaîne logistique; Synchronisation de la production dans une chaîne logistique; kanban; Production synchrone; Point de Pénétration de commande;

Exploitation of the knowledge of the final demand in the piloting of a logistics chain.

The transition from synchronous supplies to synchronous production represent a possible alternative to the neighbourhood logistics configurations, especially in the automotive industry. It allows to gain, on certain conditions, efficiency and more manoeuvrability faced with a strong variability of the demand on the supply chain. The utilization of the Order Penetration Point (OPP) will introduce problems in piloting production between clients and suppliers processes. This article is based on several working assumptions which form an algorithm for the resolution of this problem resulting from an analysis of two industrial cases with stochastic models.synchronous production; supply chain; anticipation; piloting of flows; order penetration point; kanban;

Production à la commande et production pour stock dans un environnement MRP

This article focuses on the monitoring of a supply chain dedicated to a mass production of strongly diversified products and more particularly in the part of this chain which contributes to the production of a set of alternate modules assembled on a work station of the assembly line. The approach of the MRP is adopted in the monitoring of that chain but the distance of the production units leads to a mixing between production to stock and production to order. The literature available on safety stock does not help in decision making. The relation that exists between frozen horizon and Order Penetration Point in MRP will be examine and the analytical relations which links planned orders of a reference to the requirements of the MPS which uses them, is established. Then we set the relations which make it possible to define, in the steady state, the quantities to produce to cope with requirements that are partially or completely random, taking into account or not the problem of quality, in order to limit the stockout risk to a predetermined level

Pilotage d'une chaîne logistique par une approche de type MRP dans un environnement partiellement aléatoire

This article focuses on the monitoring of a supply chain dedicated to the mass production of strongly diversified products. In particular we are interested in the part of this chain that contributes to the production of a set of alternative modules assembled on a work station of one or several assembly lines, whose production levels are stable. The customers' demand structures are assumed to be known. When the production of a component is drawn by requirements of the MPS that are beyond the frozen horizon, this component cannot be built-toorder. We provide and illustrate analytical solutions, adapted from the periodic order policies, to define scheduled orders of components to be produced partly or wholly to stock. Additional relations are provided to face disturbances induced by quality problems

Optimal stock-out risk for a component mounted on several assembly lines in case of emergency supplies

This article focuses on the calculation of the optimal stock-out risk for a component, which is used by alternative modules mounted on several assembly lines. The studied context is a supply chain dedicated to the mass production of highly diversified products, which is common in the automotive industry. The Material Requirement Planning (MRP) approach is adapted for the monitoring of this chain; however, the distance between the production units leads to mix between production to stock and production to order for the component of interest. To prevent stock-out propagation along the downstream part of the supply chain, use of an emergency supply is triggered prior to its occurrence. The definition of the optimal safety stock and the associated optimal stock-out risk, are based on a monoperiod model that considers the cost of a safety stock and the costs incurred by the emergency supply (transportation and production). The analytical solutions that are dependent on these costs are illustrated in this study

L'effet coup de fouet dans la chaîne logistique : une littérature contingente et incomplète

L'effet coût de fouet (ECF) correspond au phénomène d'amplification croissante de la variabilité de la demande en remontant le long de la chaîne logistique (CL). Il fait l'objet d'une attention soutenue par les chercheurs depuis une quinzaine d'années et préoccupe les gestionnaires de CL parce qu'il est une cause importante de perte d'efficacité et d'efficience dans la CL. Le partage d'informations entre acteurs de la CL est généralement considéré comme l'un des principaux moyens de réduction de l'ECF. Une cinquantaine d'articles portant sur ces thèmes et parus dans les revues considérées comme majeures ont été étudiés. Les grilles d'analyse utilisées permettent de mettre en évidence le caractère très contingent de nombreuses conclusions et l'existence de lacunes importantes dans les investigations conduites, notamment en ce qui concerne l'ECF se produisant dans la partie productive de la CL

Monitoring of the upstream part of a supply chain dedicated to the customized mass production with a revisited version of MRP

This article focuses on the monitoring of a supply chain dedicated to the mass production of strongly diversi-fied products. Specifically, we are interested in the part of this chain that contributes to the production of a set of alter-native modules assembled on a work station of one or several assembly lines, whose production levels are stable. The MRP approach is adopted for the monitoring of this chain. The distance between the production units leads to a mix between production to stock and production to order. In this article, we establish the relations that allow us to define, in a steady state, the quantities to produce that address the requirements of the Master Production Schedule and that are partially or completely random to limit the stockout risk to a very low predeter