Abstract
Factory Physics provides mathematical model to maximize the throughput（TH） under admitting the existence of operation variability such as delay, failure and set-up, in contrast with Japanese approach tends to strive for Kaizen denying any variability even though sacrificing the TH. This article takas up the two topics form Factory Physics. One is a scientific evaluation method of process performance based on the Little’s law, TH＝WIP（work-in process）/CT（cycle time）, which also gives comprehensive orientation of Kaizen while maintaining the TH. The other is a quantitative evaluation how significantly and qualitatively each variability effects on the CT extension. In addition, mathematical formulation of the pull methods of “Kanban” and the CONWIP（ Constant Work In Process） introduced in Factory Physics are provided and compared. Consequently it is suggested the CONWIP is the best control method by its autonomous WIP adjustment function, and effectively applied even for supply chain situation under the IoT environment.
