Short Term Scheduling
Introduction
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What – Scheduling or timing of
operations
Where – Timing of operations affects
the overall strategy
Why – Reduce costs, improve response
Scheduling
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Forward Scheduling
Backward scheduling
Scheduling criteria
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Minimize completion time
Maximize utilization
Minimize work-in-process
Minimize customer waiting time
Objective: Optimize resources so that
production objectives are met
Scheduling in ProcessFocused Work Centers
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Job shop, low volume, high variety
Schedule incoming orders without violating
capacity constraints
Check availability of tools and materials
before releasing an order
Establish due dates and check progress
Check work in progress
Provide feedback
Monitor work efficiency statistics
Loading Jobs in Work Centers
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Input-output control
Gantt charts
Sequencing Jobs at Work
Centers
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Priority Rules
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First Come, First Served
Shortest Processing Time
Earliest Due Date
Longest Processing Time
Critical Ratio
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Time Remaining / Workdays Remaining
Highest Critical Ratio is selected for
processing next
Limitations of Rules
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Scheduling is dynamic
Rules do not look upstream or
downstream
Rules do not look beyond due dates
Finite Scheduling
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Computerized
Short Term
Graphical
Interactive
Constraints and Bottlenecks
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Limit output in the production sequence
Increase capacity
Reroute work
Change lot size
Change work sequence
Accept idleness