High value at low cost Methods for supply chain efficiency

Sammanfattning: This thesis deals with four areas of research:  Economic lot scheduling problems (ELSP),  Order quantities in a production line,  Economic remanufacturing problems, and  Performance-based logistics (PBL). The overall purpose of this thesis is to explore and develop methods to increase efficiency in supply chains. More specifically, the aims of this research are: [1] to develop a solution procedure that finds a feasible minimum cost production schedule for a ’single machine multiproduct process’, [2] to investigate how the order quantity affects the performance of a production line, [3] to investigate how the yield rate affects the economic remanufacturing quantity under different carbon emission regulations, and [4] to summarise previously reported benefits and drawbacks of performance-based logistics and to explore critical aspects of implementation. The results of the research on the first aim include a mapping of the ELSP field over 100 years, a mathematical derivation of the inventory holding cost for solutions with unequal production periods, and a solution procedure that can be used to minimise production costs and thus enhance efficiency. The research on the second aim contributes to the understanding on how process parameters affect lead time and production rate in a production line. That knowledge can be used as a guideline for how to handle e.g. order quantity, setup time, work in progress restrictions and cycle time variations to improve the efficiency of a production line. The results of the research on the third aim include a method to calculate the economic remanufacturing quantity under different carbon emission regulations, which remanufacturers can use to minimise costs and thus enhance efficiency. This research also contributes to the understanding of how the economic remanufacturing quantity is affected by varying yield rate. Finally, the research on the fourth aim contributes to the understanding of the driving forces and obstacles of PBL and clarifies relationships to other research fields. The research sheds light on ’hidden’ costs of PBL and emphasises the need for more evidence regarding the profitability of PBL, since there is an obvious risk that the cost of e.g. mitigating business risks exceeds the gains. Keywords: Economic lot scheduling problems, ELSP, Order quantity, Production lot, EOQ, Production line, Lead time, Remanufacturing, Carbon emission regulation, Yield rate, Performance-based logistics, PBL, Performance contracting, Supply chain integration, Operations management.