Transcript Scheduling
Scheduling
Characteristics of a “job”
Constituent operations
Due date
Time of arrival in shop
Starting time
Completion time
Flow time
Lateness
Characteristics of a
schedule
Two basic types of scheduling
Work-force
scheduling
Operations scheduling
Operations Scheduling
short-term plans designed to
implement the master
production schedule
job
shop
flow shop
Timing of job/operations
scheduled (Gantt chart)
Job
or activity progress chart
Machine chart
For n jobs, each requiring m
machines there are (n!)m possible
schedules
Measures
Average
flow time of jobs
Average lateness of jobs
Makespan
Which of these would
Goldratt have said
Idle time
was best?
Past Due
WIP
Utilization
Scheduling heuristics
FCFS – first come, first served
SPT – shortest processing time
EDD – earliest due date
Information Needed for
Scheduling
Question:
What information
do you feel is needed to
accurately schedule an
operation?
Scheduling Class Activity
At the beginning:
400 birch in inventory
100 cherry past due
Equipment is set up for cherry
Scheduling Game Process.
I will give you demand for week
Decide on how much of each type to process –
don’t forget open orders & birch forecast!
Record on decision log
Make a feasible schedule (don’t forget setups)
Turn in decision for week to me
When complete wait for actual birch demand for
week
Calculate profit/loss – give total to me
Get demand for new week