About that feature
The feature is located in Planning program > Optimization > Constraint configuration.
It is available since DELMIA Ortems release 2021.
It was implemented to improve the operator allocation process. Indeed, before implementing this feature, the scheduling process in term of operator allocation was performed as follow:
- without taking operators into account, the operations are positioned on their grouping & machines and planned in the machine sequence according to the scheduling criteria
then
- operators are assigned to the operation/machine requiring operators WITHOUT modifying the sequence of operations on the machines.
As a consequence, when an operator is not available, the operation requiring that operator is postponed until the operator’s availability, without reconsidering the machine sequence, and therefore likely to create holes in the plan.
Example to illustrate the situation without that feature
Let’s take the following example, very simple and not realistic but helpful to better understand the way it works:
Only 3 operations:
Only 2 operators:
Only 1 machine “Machine 1”.
The scheduling criterion is “Minimize operation end date”.
Not taking into account the availability of operators, the machine sequence is:
Result when "Preassign operators when scheduling" is not enabled:
- without taking operators into account, the operations are positioned on their grouping & machines and planned in the machine sequence according to the scheduling criteria
- operators are assigned to the operation/machine requiring operators WITHOUT modifying the sequence of operations on the machines.
What will change if "Preassign operators when scheduling" is enabled?
With « Preassign operators when scheduling » setting activated, the optimization process is slighty different:
During the scheduling optimization, if an operation requires a not yet available operator, the operation is managed as if it has a Fixed Start Date = Operator availability. That operation, not planed yet, can be scheduled immediately because it belongs to the group of operations that can be scheduled immediately. BUT the scheduling criteria may prioritize other operations. If these criteria are for example prioritizing minimum operation start date, it is likely that the gap until the operator availability can be filled with other operations not having such a constraint.
This reduces the holes in the plan in case of operators not available. However the ability to fill the holes depends on the scheduling criteria used.
Using a criterion that targets to prioritize the minimum operation date is more efficient to fill the gaps.
On our same example, the result will be the following one:
