A structural methodology for managing manufacturing lead times in make-to-order companies

Abstract This paper extends the ideas put forward in an earlier EJOR article to develop a methodology for controlling manufacturing lead times. Past approaches have concentrated on scheduling a given set of orders through the shop floor in some optimal fashion to meet their specified delivery dates. This is clearly sub-optimal since it covers only part of the total lead time. It is shown that a higher level approach is more appropriate in which the order book is deliberately moulded into a shape that can be produced profitably. This should be achieved at the customer enquiry stage, when the prices and delivery dates to quote are determined. Hence a structural approach has been adopted which includes customer orders planning and job release functions. The basic concepts developed include a hierarchy of backlogs of work responsible for a consequent hierarchy of lead times that add up to the total delivery lead time. Input/output control procedures aim at maintaining the backlogs, and hence lead times, within norms set by management.