Most approaches to classical scheduling problems are unable to cope with alternate routes, but simulation is one approach that may be used. Similarly, most computer aided production management systems are unable to handle alternate routes because of the increased complexity in file structure and management. On the shop floor however, alternate routes are used to meet short-term capacity problems, although some managers feel that quality may be compromised and complexity increased. Increased awareness of the benefits of flexibility must now question routing flexibility and subsequently flexibility in operation sequence. Characteristics of alternate routing are stated, and rules for choosing an alternate route for a job are formulated. A simulation model was developed of a simple machine shop comprising up to six machines to process batches of four component types. Setting up times, breakdown patterns and inter-operational transport time are included in the model. Using the simulation model, a number of rules were tested on single operation alternates and partial route alternates. Two rules work well for different purposes. On single operation alternates, a forced ratio rule achieves workload balance while a rule which examines waiting workload achieves the shortest flowtimes. It is shown that balancing workload on partial routes can incur a penalty on flowtime. Good flowtimes on partial routes may be achieved by using a forced ratio rule or by examining waiting workloads.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:302723 |
| Date | January 1990 |
| Creators | Grinsted, Susan Eileen |
| Publisher | University of Warwick |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://wrap.warwick.ac.uk/108489/ |
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