Structuring postponement strategies in the supply chain by analytical modeling

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Measuring plant complexity in food supply chain

openbiblioteca DT

Modular product development for mass customization

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Electronic Part Total Cost Of Ownership And Sourcing Decisions For Long Life Cycle Products

The manufacture and support of long life cycle products rely on the availability of suitable parts from competent suppliers which, over long periods of time, leaves parts susceptible to a number of possible long-term supply chain disruptions. Potential supply chain failures can be supplier-related (e.g., bankruptcy, changes in manufacturing process, non-compliance), parts-related (e.g., obsolescence, reliability, design changes), logistical (e.g., transportation mishaps, natural disasters, accidental occurrences) and political/legislative (e.g., trade regulations, embargo, national conflict). Solutions to mitigating the risk of supply chain failure include the strategic formulation of suitable part sourcing strategies. Sourcing strategies refer to the selection of a set of suppliers from which to purchase parts; sourcing strategies include sole, single, dual, second and multi-sourcing. Utilizing various sourcing strategies offer one way of offsetting or avoiding the risk of part unavailability (and its associated penalties) as well as possible benefits from competitive pricing. Although supply chain risks and sourcing strategies have been extensively studied for high-volume, short life cycle products, the applicability of existing work to long life cycle products is unknown. Existing methods used to study part sourcing decisions in high-volume consumer oriented applications are procurement-centric where cost tradeoffs on the part level focus on part pricing, negotiation practices and purchase volumes. These studies are commonplace for strategic part management for short life cycle products; however, conventional procurement approaches offer only a limited view for parts used in long life cycle products. Procurement-driven decision making provides little to no insight into the accumulation of life cycle cost (attributed to the adoption, use and support of the part), which can be significantly larger than procurement costs in long life cycle products. This dissertation defines the sourcing constraints imposed by the shortage of suppliers as a part becomes obsolete or is subject to other long-term supply chain disruptions. A life cycle approach is presented to compare the total cost of ownership of introducing and supporting a set of suppliers, for electronic parts in long life cycle products, against the benefit of reduced long-term supply chain disruption risk. The estimation of risk combines the likelihood or probability of long-term supply chain disruptions (throughout the part's procurement and support life within an OEM's product portfolio) with the consequence of the disruption (impact on the part's total cost of ownership) to determine the "expected cost" associated with a particular sourcing strategy. This dissertation focuses on comparing sourcing strategies used in long life cycle systems and provides application-specific insight into the cost benefits of sourcing strategies towards proactively mitigating DMSMS type part obsolescence

Concurrent Design of Assembly Plans and Supply Chains: Models, Algorithms, and Strategies.

Assembly planning and supply chain designs are two inter-dependent activities in product development. The traditional sequential approach of designing the supply chain after completing assembly planning results in long lead time for product realization and sub-optimal product cost. The weakness of the sequential method is exacerbated nowadays as product proliferation brings more challenges to assembly system design and supply chain management. Making concurrent decisions on assembly plans and supply chain configurations is a desirable strategy. However, due to the complexity of both assembly representations and supply chain modeling, there have been limited systematic models, optimization algorithms, or deep understanding of the interaction between assembly-plan and supply-chain designs. This dissertation first analyzes and compares existing assembly representation methods. Hyper AND/OR Graph (HAG) is then developed to incorporate both assembly planning and supply chain configuration information by adding one additional layer representing supplier information on top of a typical assembly AND/OR graph. Based on HAG, a DP based algorithm with a polynomial complexity for typical assembly products is developed to generate the assembly plans and supplier assignment at the optimal cost. For the problem with a lead time constraint, a revised DP algorithm with a pseudo-polynomial complexity is also presented. Under the scenario of product family designs, an investigation is carried out on the optimal strategies to design assembly supply chains when commonality is limited between products in the family. The impact of product variety on safety inventory is derived and then evaluated with a performance measure. Strategies of prioritized differentiation and branch balancing are suggested for optimal process sequencing and assembly decomposition. The outcome of this research are threefold: (1) it establishes a foundation for the research on integrated designs of assembly plans and supply chains as well as other concurrent design problems; (2) it offers a tool for integrated assembly plan and supply chain designs using which manufacturers can shorten the product development time, lower the product cost, and increase the responsiveness to fluctuations in supply chains; and (3) it provides a measure of the impact of product variety on inventory and insightful strategies to manage complicated assembly supply chains.PhDMechanical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/133210/1/hekuang_1.pd

Decision makings in key remanufacturing activities to optimise remanufacturing outcomes : a review

The importance of remanufacturing has been increasing since stricter regulations on protecting the environment were enforced. Remanufacturing is considered as the main means of retaining value from used products and components in order to drive a circular economy. However, it is more complex than traditional manufacturing due to the uncertainties associated with the quality, quantities and return timing of used products and components. Over the past few years, various methods of optimising remanufacturing outcomes have been developed to make decisions such as identifying the best End-Of-Life (EOL) options, acquiring the right amounts of cores, deciding the most suitable disassembly level, applying suitable cleaning techniques, and considering product commonality across different product families. A decision being made at one remanufacturing activity will greatly affect the decisions at subsequent activities, which will affect remanufacturing outcomes, i.e. productivity, economic performance effectiveness, and the proportion of core that can be salvaged. Therefore, a holistic way of integrating different decisions over multiple remanufacturing activities is needed to improve remanufacturing outcomes, which is a major knowledge gap. This paper reviews current remanufacturing practice in order to highlight both the challenges and opportunities, and more importantly, offers useful insights on how such a knowledge gap can be bridged