Just-in-time manufacturing system: a periodic pull system

Abstract

The just-in-time manufacturing system, as developed in the Toyota Motor Co., may be stated as producing or stocking ‘only the necessary items in necessary quantities at the necessary time’. When the just-in-time concept is applied to an industrial material management system, it is called a pull system, which means that the amount and time of material flow are determined by the rate and time of the actual stock consumption. Actually, in Toyota, this pull system is operated manually by means of a kanban, a sort of card or tag.

As an alternative to a kanban method, a periodic pull system (PPS) is developed as an operating policy of practising a Pull system. Due to the fact that, in a PPS, the manual information processing time of a kanban method is replaced with an instant on-line computerized processing, the material lead time is much shorter than that of a kanban system. This results in better system performance such as less lead time inventory and faster system response.

A PPS is formulated mathematically and a solution approach is provided for target stock levels, as well as the analysis of the fluctuations of in-process material flow, on-hand stock levels, target availability, etc.