Development of Drum-Buffer-Rope scheduling software to support a “what if” approach to scheduling job shops
Date
2006-03
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Stellenbosch : University of Stellenbosch
Abstract
The Theory of Constraints is a management philosophy based on the underlying assumption that
only a few constraining factors limit the throughput of the entire system. Drum-Buffer-Rope is
the production logistical solution of the Theory of Constraints. It is the implementation of
Constraints Management on the manufacturing shop floor, to manage physical resource
constraints. Drum-Buffer-Rope was designed with the purpose of increasing Throughput, while
simultaneously decreasing Inventory, and minimising Operating Expense. It aims to accomplish
these goals by focusing on simplifying and therefore reducing variability in the production
process, and ultimately protecting order due dates against disruptions.
The dynamic conditions under which typical job shops operate can make Constraints
Management of the resource constraints a cumbersome task. By following a “What If” approach
to the scheduling process, the scheduler can play an interactive role in developing practical shop
floor schedules. In this way the scheduler can see the results of his/her ideas on the shop floor
situation quickly as immediate feedback is provided. The Drum-Buffer-Rope methodology only
finite schedules certain points in the manufacturing process therefore scheduling calculations can
be performed quickly if done in software. This makes it possible for the scheduler to analyse
various scenarios in a short period of time and allowing the development of near optimal shop
floor schedules by following a “What If” approach to scheduling.
In this project, new developments in the field of Drum-Buffer-Rope were investigated, and the
newly developed Simplified Drum-Buffer-Rope methodology was researched. The
methodologies were incorporated in a fully developed software package that uses Drum-Buffer-
Rope or Simplified Drum-Buffer-Rope to marry the intrinsic knowledge of the shop-floor worker
with modern day computer technology to create production schedules that can be released to the
shop floor. Schedules are created rapidly enough by the software to enable the scheduler to
follow a “What If” approach to create near optimal shop floor schedules. The developed software
was used with live data from a South African job shop to illustrate the “What If” approach to
Simplified Drum-Buffer-Rope scheduling. The results show that throughput can be increased and
operating expense decreased, therefore increasing bottom line results, by analysing various
scenarios.
Description
Thesis (MScEng (Industrial Engineering))--University of Stellenbosch, 2006.
Keywords
Dissertations -- Industrial engineering, Theses -- Industrial engineering, Theory of constraints (Management), Production scheduling