استفاده از تدارکات شخص ثالث به منظور پیاده سازی سیستم تولید به هنگام با حداقل هزینه در یک محیط جهانی

The integration of the Just-In-Time (JIT) system with supply chain management has been attracting more and more attention recently. Within the processes of the JIT system, the upstream manufacturer is required to deliver products using smaller delivery lot sizes, at a higher delivery frequency. For the upstream manufacturer who adopts sea transportation to deliver products, a collaborative third party logistics (3PL) can act as an interface between the upstream manufacturer and the downstream partner so that the products can be delivered globally at a lower cost to meet the JIT needs of the downstream partner. In this study, a quantitative JIT cost model associated with the application of third party logistics is developed to investigate the optimal production lot size and delivery lot size at the minimum total cost. Finally, a Taiwanese optical drive manufacturer is used as an illustrative case study to demonstrate the feasibility and rationality of the model.

With the globalization of businesses, the on-time delivery of products through the support of a logistics system has become more and more important. Global corporations must constantly investigate their production systems, distribution systems, and logistics strategies to provide the best customer service at the lowest possible cost. Goetschalckx, Vidal, and Dogan (2002) stated that long-range survival for international corporations will be very difficult without a highly optimized, strategic, and tactical global logistics plan. Stadtler (2005) mentions that the activities and processes should be coordinated along a supply chain to capture decisions in procurement, transportation, production and distribution adequately, and many applications of supply chain management can be found in the literature (e.g. Ha and Krishnan, 2008, Li and Kuo, 2008 and Wang and Sang, 2005). Recently, the study of the Just-In-Time (JIT) system under a global environment has attracted more attention in the Personal Computer (PC) related industries because of the tendency towards vertical disintegration. The JIT system can be implemented to achieve numerous goals such as cost reduction, lead-time reduction, quality assurance, and respect for humanity (Monden, 2002). Owing to the short product life cycle of the personal computer industry, downstream companies usually ask their upstream suppliers to execute the JIT system, so that the benefits, like the risk reduction of price loss incurred from inventory, lead times reduction, on-time delivery, delivery reliability, quality improvement, and lowered cost could be obtained (Shin, Collier, & Wilson, 2000). According to the JIT policy, the manufacturer must deliver the right amount of components, at the right time, and to the right place (Kim & Kim, 2002). The downstream assembler usually asks for higher delivery frequency and smaller delivery lot sizes so as to reduce his inventory cost in the JIT system (Kelle, khateeb, & Miller, 2003). However, large volume products are conveyed using sea transportation, using larger delivery lot sizes to reduce transportation cost during transnational transportation. In these circumstances, corporations often choose specialized service providers to outsource their logistics activities for productivity achievement and/or service enhancements (La Londe & Maltz, 1992). The collaboration of third party logistics (3PL) which is globally connected to the upstream manufacturer and the downstream assembler will be a feasible alternative when the products have to be delivered to the downstream assembler through the JIT system. In this study, the interaction between the manufacturer and the 3PL will be discussed to figure out the related decisions such as the optimal production lot size of the manufacturer and the delivery lot size from the manufacturer to the 3PL, based on its contribution towards obtaining the minimum total cost. In addition, the related assumptions and restrictions are deliberated as well so that the proposed model is implemented successfully. Finally, a Taiwanese PC-related company which practices the JIT system under a global environment is used to illustrate the optimal production lot size and delivery lot size of the proposed cost model.

How to implement the JIT system under a global environment has been attracting increasing attention. Since the downstream assemblers ask the upstream manufacturers to deliver products using the JIT system, the integration of 3PL provider will become an extremely important partner in implementing the JIT system under a global environment in the future. This study presents a cost model to investigate the relationships among the manufacturer, the 3PL provider, and the assembler. Accordingly, this study presents the following conclusions: 1. Some products with larger delivery lot sizes are suitable for sea transportation. When these products have to be delivered from the upstream manufacturer to the downstream assembler under a JIT system, the 3PL provider can collaborate as an interface between the upstream manufacturer and the downstream assembler. The products can be delivered from the manufacturer to the 3PL provider by optimal delivery lot size to reduce the transportation cost, and the products can also be delivered from the 3PL provider to the assembler using smaller delivery lot sizes at a higher delivery frequency to satisfy the assembler’s needs. A quantitative cost model which can be executed using a JIT system associated with the 3PL is proposed in order to investigate the most cost-effective transportation container type, the optimal production lot size and delivery lot size of the manufacturer which gives the lowest total cost. 2. The constraint of delivery lot size, qjqj, has been investigated for feasibility and rationality. If the model is subjected to the constraint given in Eq. (23), (1) The transportation cost from the manufacturer to the 3PL provider will not increase since the number of shipments will not be increased; (2) The average inventory kept with the 3PL provider will be the same at each interval L, which implies that the inventory cost of the 3PL provider can be figured out precisely, and (3) The inventory cost will also be reduced since the delivery lot size, qjqj, is the multiple of the demand of the downstream assembler, d, which implies that the issue of remaining inventories will not arise at the 3PL provider’s end at the end of each interval L. In addition, the proposed model can be subjected to the constraint shown in Eq. (23) more easily if the delivery lot size of the jth transportation container type, QjQj, is much larger than the demand of the downstream assembler, d, i.e. Qj≫dQj≫d. When the products are delivered from the manufacturer to the 3PL provider by sea transportation using larger delivery lot sizes, and then delivered from the 3PL provider to the assembler under a JIT system using a smaller delivery lot size, the manufacturer can use this cost model to obtain the optimal economic delivery lot size and exact number of shipments with the minimum total cost. Finally, the perspective on globalization has been integrated into supply chain management due to the tendency towards vertical disintegration of the industry. Other issues such as the global delivery strategy, inventory system, and the integration of the collaborative 3PL providers etc. are topics worth exploring in future studies.