Compress the Schedule

Compress Idle Time

Key Concepts

This feature is used to remove idle time in the schedule by “compressing” activities to the left of the schedule without changing their sequence or violating any constraints. Manual scheduling can result in undesired gaps in the schedule where resources are unintentionally left idle. Compressing the schedule will remove such gaps.

Options

  • Compress operations starting before: This specifies a limit to the compress to avoid “pulling in” operations that are not needed until far in the future.

    • End of Frozen Span: If selected, then the system will only compress operations that start before the end of the frozen span.
    • End of Plant Stable Span: If selected, then the system will only compress operations that start before the end of the plant stable span.
    • End of schedule: If selected, then the system will only compress operations that start before the end of the schedule.
    • Specific Date/Time: If selected, then the system will only compress operations that start before a specified date and time.
  • Release Rule to use: This prevents operations to start too early by specifying the release dates that should be used.
    • JIT With Resource HeadStart: The system will apply the number of HeadStart days specified for each resource to the activities’ JIT start.
    • JIT With Global HeadStart: Selecting this option will allow the user to specify the number of JIT Slack days to be applied to the activities’ JIT start.
    • Drum-Buffer-Rope: Selecting this option will allow the user to specify the number of JIT Slack days to be applied to the capacity-constrained resource when the schedule is compressed.

JIT Compress

Key Concepts

The Just In Time Compress function will shift operations to the future while preserving their sequence to reduce early production and accommodate for high future capacity loads. When this button is clicked, the activities will be rescheduled to their Activity JIT date while the sequence of activities remains the same.