Forward Scheduling vs Backward Scheduling
Forward scheduling is a done if no product is available on the material availability date calculated by backward scheduling. The system does an availability check to determine the first possible date when the product will be available. This new material availability date forms the starting point for scheduling the remaining activities. The loading time, pick/pack time, transit time, and transportation lead time is added to the new material availability date to calculate the confirmed delivery date.
Backward scheduling is the calculation of deadline dates: the arrival time at the customer site is calculated as the earliest possible goods receipt time at the customers unloading point on the requested delivery date. All four of the delivery and transportation scheduling lead times are subtracted from the customer’s requested delivery date to determine if this date can be met.
The transit time, loading time, and pick/pack time are subtracted from the customer’s requested delivery date to calculate the required material availability date.
The system calculates backward scheduling as follows:
- Requested delivery date minus transit time = Goods issue date
- Goods issue date minus loading time = Loading date
- Loading date minus transportation lead time = Transportation scheduling date
- Loading date minus pick/pack time = Material availability date
By default, the system will calculate delivery dates the closest day, taking into consideration the working days of the shipping point and a rounding profile. In this case, the system assumes a 24 hour work day and lead times can be entered in days up to 2 decimal points. This is referred to as daily scheduling.
Precise scheduling calculated down to the day, hour and minute are supported. This allows the scheduling of a delivery within a single day. It is activated by maintaining the working hours for a particular shipping point.
Backward scheduling is always carried out first. If the material availability date or transportation scheduling date is calculated to be in the past, the system must then use forward scheduling.