How to consider substitute component under two-phase plan(MPS vs MRP).

Question

We try to run two-phase plan: Production plan and Manufacture Plan in ASCP.
We hope our planner can review production plan result and modify system suggestion date or qty for assemble component plan order.
Then we run Manufacture plan setting demand source is from production plan and "use substitute component" is checked in decision rule, we hope this Manufacture plan can consider substitute component.
But the Manufacture plan didn't consider substiute component.
How to make Manufacture plan consider substiute component when we set demand source is from production plan .

Answer 1

Stacey,
I understand your requirement. I also believe that the manufacturing plan should be able to plan substitute components, but it would take quite a bit of analysis to understand why it was not working correctly. If you want to pursue that approach, I would recommend you start a SR with oracle support to troubleshoot.
The most typical approach with two plans is to have the production plan constrained and attempt to use available substitute components marked as critical. If that is the case, these "critical item" orders would not be replanned in the second plan. Your purchasing planner would not be able to firm planned orders in the second manufacturing plan, but could only update dates and release from that plan. At best case, any changes would be overwritten entered by the purchaing planner for items controlled in the production plan would be overwritten in the next cycle.
The best use of a two plan approach is to simplify constrained planning efforts by have a second unconstrained plans for most items and a smaller constrained plan driving the process. That is not your intent, so you might want to stay with one plan. You will always have some lag in these planners actions in a two plan process, so I don't know if this approach is driving any real benefit for you from a one plan approach. In either approach you will have planners stepping on each other and having to review exceptions, or better yet... talk to each other to review plans.
So...
1. If your intent is to limit the complexity of the constrained plan, the two plan approach has benefits
2. If point # 1 is not your intent, and you are focused on allowing planners to react faster and communicate with each other as they plan their schedules, stay with a one plan approach.
You said
"Our planner will release the plan orders which suggest start date is inside two weeks. But when they review the result and release the plan order , purchase planner review the same plan and issue purchase request in the same time. It will happen some problem, purchase planner will obey system's purchase suggestion but can't meet the demand of those plan orders that production planner has released."
An assembly planner should not be releasing orders within two weeks when the materials are unavailable. That should not happen with a constrained plan unless they created an override the system recommendations. With unconstrained plans, the best you can do is implement a time fence control to prevent this and review exceptions.
I think the best you can do here is implement this process as constrained with substitutes considered for the Assembly planner. Then usining one plan, have the purchasing planner implement their orders based on the latest information. They should use safety stock planning techniques and be looking at a lonegr horizon for demands. They should also communicate these plans to each otherKevin