OPMT 303: Scheduling
22 Cards in this Set
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Scheduling
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Establishing the timing of the use of equipment, facilities and human activities in an organization.
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Effective _____ can yield cost savings and increases in productivity.
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scheduling
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______ decisions must be made within the constraints established by many other decisions.
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characterized by standardized equipment and activities that provide identical or similar operations.
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High Volume Systems
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Few ____ ____ are completely devoted to a single product or service, most handle a variety of sizes and models.
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Flow Systems
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What are the success factors of a flow system?
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1) process and product design.
2)rapid repair
3)preventive maintenance
4)optimal product mixes
5)minimize quality problems
6)reliability and timing of supplies.
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Typically produce standardized output; but the volume is not large enough to warrant continuous production.
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Intermediate volume systems
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What are the 3 basic issues of intermediate volume systems?
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Run size of jobs, timing of jobs, and sequencing of jobs.
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What are the two difficulties companies experience when using intermediate volume systems?
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Setup costs and usage rates.
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Gantt chart that shows the loading and idle times for a group of machines or list of departments
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Load Chart
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Gantt chart that shows the orders or jobs in progress and whether they are on schedule.
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Schedule Chart
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when jobs are assigned to workstations without regard to the capacity of the work center.
If the center does not complete production of the load in one period, the incomplete work is basically added to the next period’s load
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infinite loading
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jobs are assigned to work centers after taking into account the work center capacity and job processing times.
The idea is not to go over capacity.
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finite loading
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scheduling ahead from some point in time.
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forward scheduling
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scheduling backwards from some due date.
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backwards scheduling
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simple heuristics used to determine the order in which jobs will be produced.
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Priority Rules
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What are some examples of priority rules?
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first come first serve (FCFS)
earliest delivery date (EDD)
critical ratio (CR)
slack per operation(S/O)
shortest processing time (SPT)
rush
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What are the assumptions of priority rules?
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1) The set of jobs is known; no new jobs arrive after processing begins; no jobs are cancelled
2)setup time is independent of processing sequence
3) setup and processing times are deterministic
4)There will be no interruptions in processing
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priority rules affect the _____ _____ of a company.
These must be selected first and then priority rules are chosen based on them.
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performance metrics
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What are some examples of performance metrics?
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job flow time - the length of time a job is at a workstation
job lateness - the difference between job completion time and job due date
job tardiness - length of time the job completion time exceeds job due date
makespan - total time needed to complete a group of jobs
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a technique that managers can use to minimize the makespan for a group of jobs to be processed on two machines or two successive work centers.
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Johnson's rule
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in order to use Johnson's rule, what conditions must be satisfied?
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1) Job time must be known and constant for each job
2) Job times must be independent of job sequence
3)All jobs must follow the same sequence
4)Job priorities cannot be used
5) All units in a job must be completed at the first work center before the job moves to the second
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OPMT 303: Scheduling