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Presentation on theme: "Scheduling."— Presentation transcript:

1 Scheduling

2 What is scheduling In a production system, it is the timing and sequencing of the use of specific resources in the system and is the final step in the decision making process of an organization before the actual transformation processes begin.

3 Scheduling Manufacturing Operations
Build A A Done Build B B Done Build C C Done Build D Ship JAN FEB MAR APR MAY JUN On time! High-volume Intermediate- volume Low-volume Service operations

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

5 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

6 Intermediate-Volume Systems
Outputs are between standardized high-volume systems and made-to-order job shops Economic run size:

7 Scheduling Low-Volume Systems
Loading - assignment of jobs to process centers Sequencing - determining the order in which jobs will be processed

8 Loading Gantt chart - used as a visual aid for loading and scheduling

9 Assignment Problem Jobs Workers
Assigning jobs to workers. There is a cost associated with a worker completing a certain job. The objective is to finish all the jobs by the workers so that the total cost is minimized. An optimal solution can be found by the Hungarian Method.

10 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.

11 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

12 Priority Rules FCFS - first come, first served
SPT - shortest processing time DD - due date CR - critical ratio S/O - slack per operation Rush - emergency Top Priority

13 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

14 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

15 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

16 Service Operation Problems
Cannot store or inventory services Customer service requests are random Scheduling service involves Customers Workforce Equipment

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