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Execution and Control (4. Capacity Control (input/ output control (I/O) in…

- - - - constraint buffer: the total processing time from when raw materials are released to the gateway operation until they reach the constraint.
      - assembly buffer: duration from the release of raw materials to a process not passing through the constraint but will eventually be combined with materials that did pass through the constraint.
      - shipping buffer: duration from when materials exit the constraint until they reach the shipping location.
- - - - backward scheduling: scheduling work backward from the due date to find the latest time the operation could start.
        ad: minimize WIP inventory levels
        disad: little time for correcting error
      - forward scheduling: earliest start date for operation.
        disad:increase inventory holding costs
      - infinite loading: calculate the capacity required at work center in the time periods required regardless of the capacity available to perform this work.
        (increase capacity by using overtime, etc.)
      - finite loading: consider capacity available when scheduling.
      - drum-buffer-rope scheduling
    - - overlapped schedule: send parts of a lot to the next operation to start while there are still some at the first operation.
        dis: increase materials handling costs
      - splitting: split the lot into smaller portions and run each portion on duplicate equipment and tooling.
        ad: reduce operation's lead time
        dis: require more capital equipments and operators
- - - - dispatch list
      - dispatching rules
        
        first come, first served (FCFS)
        earliest job due date (EDD)
        earliest operation due date (ODD)
        shortest process time (SPT)
        critical ratio (CR)= actual processing time remaining/ lead time remaining
        slack time= time remaining for an order - the sum of remaining setup & run time for an order
  - - - cumulative variance (inputs)= previous cumulative variance + actual input - planned input
        cumulative variance (outputs)= previous cumulative variance + actual output - planned output
        planned backlog= previous planned backlog + planned input - planned output
        actual backlog= previous actual backlog + actual input - actual output