Modeling optimal tradeoffs for lean and sustainable manufacturing

The evolution of industry has been predicated on the belief that the environment provides endless resources of energy and materials as well as stable and insensitive ecosystem. The limitations of this assumption are now obvious—not only scientists but also society and industry are aware of the fact there are limits on this planet which our economies are about to reach within this century, and a lot of research has been done to understand the relationship between industry and the environment. The relentless push for efficiency, achieved by management methods such as just-in-time, Lean principles etc. that have been playing an important role in industry for the last two decades, must now be relegated to the objective of Sustainability as the primary objective for manufacturing in the twenty-first century. Although it has been stated in many scientific researches that Lean and Green complement each other in many areas, there are various situations in current manufacturing practices where they are contrary. This study explores the limits to the application of Lean principles without compromising Sustainable goals. A simple case study examining the effects of changeovers as well as variant complexity for manufacturing is used to contrast the solution proposed for maximum efficiency against that for Sustainable manufacturing. A method for prioritizing each objective is proposed and solution algorithms are detailed. The results indicate that, depending on the setting, Lean and Green optimized solutions are not identical. However, the concepts that are developed show that tradeoffs between those solutions are possible and applicable. This study serves as a stepping stone for further research exploring more sophisticated solution methods determining optimal tradeoffs between Lean efficiency and Sustainability based on real manufacturing scenarios