1. 15-1Scheduling William J. Stevenson Operations Management 8 th edition

2. 15-2Scheduling CHAPTER 15 Scheduling McGraw-Hill/Irwin Operations Management, Eighth Edition, by William J. Stevenson Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved.

3. 15-3Scheduling  Scheduling: Establishing the timing of the use of equipment, facilities and human activities in an organization  Effective scheduling can yield  Cost savings  Increases in productivity Scheduling

4. 15-4Scheduling High-Volume Systems  Flow system: High-volume system with Standardized equipment and activities  Flow-shop scheduling: Scheduling for high- volume flow system Work Center #1Work Center #2 Output

5. 15-5Scheduling Build A A Done Build B B Done Build C C Done Build D Ship JANFEBMARAPRMAYJUN On time! Scheduling Manufacturing Operations High-volume Intermediate- volume Low-volume Service operations

6. 15-6Scheduling High-Volume Success Factors  Process and product design  Preventive maintenance  Rapid repair when breakdown occurs  Optimal product mixes  Minimization of quality problems  Reliability and timing of supplies

7. 15-7Scheduling Intermediate-Volume Systems  Outputs are between standardized high- volume systems and made-to-order job shops  Run size, timing, and sequence of jobs  Economic run size:

8. 15-8Scheduling Scheduling Low-Volume Systems  Loading - assignment of jobs to process centers  Sequencing - determining the order in which jobs will be processed  Job-shop scheduling  Scheduling for low-volume systems with many variations in requirements

9. 15-9Scheduling Gantt Load Chart  Gantt chart - used as a visual aid for loading and scheduling Figure 15.2

10. 15-10Scheduling  Infinite loading  Finite loading  Vertical loading  Horizontal loading  Forward scheduling  Backward scheduling  Schedule chart Loading

11. 15-11Scheduling Sequencing  Sequencing: Determine the order in which jobs at a work center will be processed.  Workstation: An area where one person works, usually with special equipment, on a specialized job.

12. 15-12Scheduling Sequencing  Priority rules: Simple heuristics used to select the order in which jobs will be processed.  Job time: Time needed for setup and processing of a job. Everything is #1 Priority

13. 15-13Scheduling Priority Rules  FCFS - first come, first served  SPT- shortest processing time  EDD - earliest due date  CR - critical ratio  S/O - slack per operation  Rush - emergency Top Priority Table 15.2

14. 15-14Scheduling 3.249.6722.17CR 2.686.3318.33EDD 2.636.6718.00SPT 2.939.0020.00FCFS Average Number of Jobs at the Work Center Average Tardiness (days) Average Flow Time (days)Rule Example 2 Table 15.4

15. 15-15Scheduling Two Work Center Sequencing  Johnson’s Rule: technique for minimizing completion time for a group of jobs to be processed on two machines or at two work centers.  Minimizes total idle time  Several conditions must be satisfied

16. 15-16Scheduling Johnson’s Rule Conditions  Job time must be known and constant  Job times must be independent of sequence  Jobs must follow same two-step sequence  Job priorities cannot be used  All units must be completed at the first work center before moving to second

17. 15-17Scheduling Johnson’s Rule Optimum Sequence 1. List the jobs and their times at each work center 2. Select the job with the shortest time 3. Eliminate the job from further consideration 4. Repeat steps 2 and 3 until all jobs have been scheduled

18. 15-18Scheduling Scheduling Difficulties  Variability in  Setup times  Processing times  Interruptions  Changes in the set of jobs  No method for identifying optimal schedule  Scheduling is not an exact science  Ongoing task for a manager

19. 15-19Scheduling Minimizing Scheduling Difficulties  Set realistic due dates  Focus on bottleneck operations  Consider lot splitting of large jobs

20. 15-20Scheduling Scheduling Service Operations  Appointment systems  Controls customer arrivals for service  Reservation systems  Estimates demand for service  Scheduling the workforce  Manages capacity for service  Scheduling multiple resources  Coordinates use of more than one resource

21. 15-21Scheduling Cyclical Scheduling  Hospitals, police/fire departments, restaurants, supermarkets  Rotating schedules  Set a scheduling horizon  Identify the work pattern  Develop a basic employee schedule  Assign employees to the schedule

22. 15-22Scheduling Service Operation Problems  Cannot store or inventory services  Customer service requests are random  Scheduling service involves  Customers  Workforce  Equipment

23. 15-23Scheduling Service Scheduling SSU1 Overview—United Airlines

24. 15-24Scheduling Service Scheduling SSU2 United Airlines Flight Schedule

25. 15-25Scheduling Schedule PS8 Painting Example (Washburn Guitar)