GOALI: Quantitative Methods for Designing Lean Buffering in Production Systems: Theory and Applications

这项研究提出了严格的定量方法的开发提供资金的精益缓冲在大批量生产系统的设计和实验验证的技术开发的工厂车间。该项目的理论部分将在密歇根大学进行，实验部分将在戴姆勒克莱斯勒底特律车轴厂进行。 在这个项目中，精益缓冲被理解为最小的缓冲能力，这是必要的，足以实现生产系统的期望吞吐量。目前，没有分析方法来选择精益缓冲，因此，生产线设计师和生产经理使用模拟和经验为基础的技术，这往往导致次优的结果。该项目的方法是基于对现有生产线的分析调查，以及随后的缓冲容量最小化，作为机器效率、生产线效率和系统中机器数量的函数。这种方法将用于具有指数分布的机器的生产线。对于非指数型机器，该项目将开发和验证一个经验法则，根据该法则，精益缓冲是停机时间变异系数的分段线性函数，斜率由指数型情况下的精益缓冲水平定义。这些结果将在戴姆勒-克莱斯勒底特律车桥厂的8.25英寸后桥生产系统中进行实验验证和实施。如果成功的话，本项目的成果将为精益生产提供理论基础。此外，生产线设计师和生产系统经理将获得一个简单的定量工具，用于设计精益系统。这一工具的实际实施将有助于提高美国工业的竞争力。

This research proposes to provide funding for the development of rigorous quantitative methods for the design of lean buffering in large volume production systems and for the experimental verification of the techniques to be developed on the factory floor. The theoretical part of the project will be carried out at the University of Michigan; the experimental part will take place at the DaimlerChrysler Detroit Axle Plant. In this project, the lean buffering is understood as the smallest buffer capacity, which is necessary and sufficient to achieve the desired throughput of a production system. At present, no analytic methods for selecting lean buffering are available and, therefore, production line designers and production managers use simulation and experience-based techniques, which often lead to suboptimal results. The approach of this project is based on analytical investigations of the production lines at hand and subsequent minimization of buffer capacity as a function of machine efficiency, production line efficiency, and the number of machines in the system. This approach will be carried out for production lines with machines having exponentially distributed up- and downtime. For non-exponential machines, the project will develop and verify an empirical law, according to which lean buffering is a piecewise linear function of the downtime coefficient of variation with the slopes defined by the level of lean buffering in the exponential case. These results will be verified experimentally and implemented within the 8.25" rear axle production system at the DaimlerChrysler Detroit Axle Plant. If successful, the results of this project will provide a theoretical foundation of lean manufacturing. In addition, production line designers and production system managers will receive a simple quantitative tool for designing lean systems. Practical implementations of this tool will contribute to increased competitiveness of the US industry.