Job release: Part of a hierarchical system to manage manufacturing lead times in make-to-order companies

A methodology to manage manufacturing lead times is currently being developed by the authors. The system is specifically designed to address the needs of small- to medium-sized make-to-order companies. It involves a hierarchical production planning system in which integration between the production and marketing functions is facilitated. Considerations of capacity are included at both of the decision levels addressed-the customer enquiry stage and the job release stage. This paper describes the job release stage, showing how it is linked with the high-level stage by controlling a hierarchy of backlog lengths. At the job release stage the released backlog length for each work centre is maintained between predetermined minimum and maximum levels. It is shown that shop floor throughput times-an important part of manufacturing lead times-can be controlled by controlling released backlog lengths. The releasing mechanism is described and it is argued that there can be many benefits of job release-including reduced shop congestion, lower work-in-progress and lower costs.