Class 9 Flashcards
Define Scheduling
establishing the timing of the use of equipment, facilities, and human activities in an organization
Define Shop floor control
when scheduling is managed by the scheduler or controller
Define sequencing
the process of determining the order in which jobs will be processed
Define Makespan
total time required to do a group of jobs
Define Gantt chart
visual aids used for loading and scheduling (used to organize and clarify the use of resources over time)
Define Load chart
a special type of gantt chart that shows loading and idle times for machines, workers etc.
Define Input/Output control chart
a process for managing work flows and queues at each work center by monitoring WIP waiting to be processed
Define Johnson’s rule
A technique to minimize the makespan of a group of jobs that have to be processed on two successive machines/workstations
2 reasons why it is difficult to schedule services
1) unable to store services
2) random nature of customer requests for service
list 7 priority rules commonly used for scheduling
1) FCFS (first come first served)
2) SPT (shortest processing time)
3) SRPT (shortest remaining processing time)
4) EDD (earliest due date)
5) MST ( Minimum slack time)
6) CR (critical ratio)
7) rush
list 4 performance rules commonly used for scheduling
1) lateness - length of time that a completion date exceeds the due date
2) Makespan - total time required to do a group of jobs
3) flow time - time a job at a particular station
4) Average WIP - average WIP=total flow time/makespan
List 3 things a scheduler can do to improve scheduling
1) set realistic due dates
2) consider splitting large jobs
3) focus on bottleneck operations
List two approaches to help schedule services
1) manage demand better
2) manage provision of services better
Calculation questions
answers in notes
define slack time
minimum time to due date less remaining processing time
