Development of Drum-Buffer-Rope scheduling software to support a 'what if approach to scheduling job shops

[摘要] The Theory of Constraints is a management philosophy based on the underlying assumption thatonly a few constraining factors limit the throughput of the entire system. Drum-Buffer-Rope isthe production logistical solution of the Theory of Constraints. It is the implementation ofConstraints Management on the manufacturing shop floor, to manage physical resourceconstraints. Drum-Buffer-Rope was designed with the purpose of increasing Throughput, whilesimultaneously decreasing Inventory, and minimising Operating Expense. It aims to accomplishthese goals by focusing on simplifying and therefore reducing variability in the productionprocess, and ultimately protecting order due dates against disruptions.The dynamic conditions under which typical job shops operate can make ConstraintsManagement of the resource constraints a cumbersome task. By following a 'What If approachto the scheduling process, the scheduler can play an interactive role in developing practical shopfloor schedules. In this way the scheduler can see the results of his/her ideas on the shop floorsituation quickly as immediate feedback is provided. The Drum-Buffer-Rope methodology onlyfinite schedules certain points in the manufacturing process therefore scheduling calculations canbe performed quickly if done in software. This makes it possible for the scheduler to analysevarious scenarios in a short period of time and allowing the development of near optimal shopfloor schedules by following a 'What If approach to scheduling.In this project, new developments in the field of Drum-Buffer-Rope were investigated, and thenewly developed Simplified Drum-Buffer-Rope methodology was researched. Themethodologies 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 workerwith modern day computer technology to create production schedules that can be released to theshop floor. Schedules are created rapidly enough by the software to enable the scheduler tofollow a 'What If approach to create near optimal shop floor schedules. The developed softwarewas used with live data from a South African job shop to illustrate the 'What If approach toSimplified Drum-Buffer-Rope scheduling. The results show that throughput can be increased andoperating expense decreased, therefore increasing bottom line results, by analysing variousscenarios.

[发布机构] Stellenbosch University