Schedule Direction

In Backwards Scheduling, the need date of the shop order is what drives the start and end dates on individual operations. For example…

If a shop order has a need date of 12/09/2020, and has 3 operations, each with 1 day of work content…

Operation 3 will be scheduled to start 1st thing in the morning of 11/09, and finish at the end of the day on 11/09 (i.e. it would finish in time for the shop orders need date).

Operation 2 will be scheduled to start 1st thing in the morning on 10/09, and finish at the end of the date on 10/09.

Operation 1 will be scheduled to start 1st thing in the morning on 09/09, and finish at the end of the date on 09/09.

Notice, that when using back scheduling, the star date on some operation can end up being in the past (indicating that you should have started working on this earlier if you wanted to achieve the need date)

In Forward Scheduling, IFS work from the earlies possible start date to schedule the individual operations. Using the same example…

Operation 1 would be planned to start 1st thing in the morning Today (11/09/2020), and finish at the end of today

Operation 2 would be planned to start 2st thing tomorrow morning (12/09/2020), and finish at the end of tomorrow

Operation 3 would be planned to start 1st thing in the morning of 13/09/2020, and finish at the end of the day on 13/09/2020

Note that when using forward planning, the end date of the last operation can be beyond the need date of the shop order (indicating that you’re going to run late).

Please note: The above examples are somewhat simplified, as additional factors come into play, such as transport times between operations, calendars applicable to the resources/work centres, etc, but I hope this gives you at least a basic understanding of the principals involved.

Kind Regards,

• Robin